P0087 fuel rail pressure low limp under high loads

[Mark Rinker]

Only 4500 miles!!!

A genunie Delco filter plugged up that quick in the middle of summer - so I know its not full of ice crystals from water in fuel... That must have been one crappy tankful, last tank was purchased in Moorhead, MN just off I94. Maybe some rancid bio-diesel blend, or a crusty underground tank?

Just my luck. 99K mile on the odometer, and I'll probably hang an injector next...just out of warranty.

[trbankii]

All it takes is one tank of the wrong stuff.

[Mark Rinker]

Well, the second time this happened - only 1,500 miles into a fresh OEM Delco fuel filter - I knew there had to be something more going on, than just bad fuel.

No smoke at idle, none under load, but watching requested and actual fuel rail pressure showed exactly what was happening...when requested gets to 22k# the actual begins to fall behind, and when it peaks at 24K# or more, the ECM catches the variance and sets the code.

A helpful and knowledeable diesel tech at www.whitesmountainchevy.com (http://www.whitesmountainchevy.com) of Casper, Wyoming verified that he has seen this before (P0087 with new fuel filter that is flowing properly) with trucks used to pull heavy equipment in the Wyoming oil fields. Said that unlike classic injector failure symptoms such as smoke at idle, this one initially had him 'scratching his head' until it became apparent that the weak injectors and/or weak high pressure pump caused the low fuel rail pressure code to be set due to their combined high return rates, rather than due to a restricted filter, which is usually the culprit.

In my case, it took a loaded trailer, Wyoming mountains, and hot engine temperatures.

They documented my situation at 101,500 miles - and I used my own ability to reset the code to continue the trip on to Salt Lake City. Code was reset about 12 times, total - always while climbing grades. Unloaded (empty) trip home was no problem.

[Duramaster]

Here is something to your P0087. We had a few trucks come in with the P0087 and went through the fuel filter routine and come to find out the P0087 would set 350 mile or so later. These particular vehicles were "HAULERS" as well. Come to find out, the flexible fuel lines at the engine and under the vehicle near the transmission would kink and cause the P0087.

Here is the bulletin.



2008)


Subject: Diesel Engine Fuel Line Repairs


Models: 2001-2007 Chevrolet Silverado Classic

2001-2007 GMC Sierra Classic

2007-2009 Chevrolet Silverado

2007-2009 GMC Sierra

Equipped with the 6.6L Diesel Engine RPO codes LB7 LBZ LLY LMM




--------------------------------------------------------------------------------

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
A dealer may need to perform a repair on the rubber portion of the fuel supply (suction) lines. The rubber section of the line could become kinked or collapse. Fuel lines that kink or collapse may induce a fuel system restriction (high vacuum gauge readings) or DTCs P0087, P0093, and/or P1093 to set.

If a technician was to suspect the rubber portion of the fuel feed line collapsing or kinking, replacement of only the rubber line is acceptable.

Recommendation/Instructions:
Complete the steps below to repair the rubber section of fuel supply line:

•Carefully cut, split, and remove the OEM crimp from both ends of the flexible hose. These crimps can be cut with a small cut-off wheel. Split the crimp into two pieces (use your discretion on first cut location, then cut directly across from, or 180 degrees from first cut). Special care must be taken not to damage the flare on the end of the steel pipe that will be reused.
•Remove the OEM crimps and flexible portion of hose from the existing supply line.
•If replacing the rubber section of the supply line, a 1/2 ID hose meeting SAE specification 100R3 is suggested. Dealers may be able to find a local supplier for this hose, or can contact the manufacturer Parker Hannifin. The replacement hose would be a 1/2" diameter Parker part number 601-8 or H017-8. To find a local distributor the Parker website can be accessed at www.parker.com
•Use worm type hose clamps (use double clamps on each end) to attach the replacement hose to the existing pipe.
The locations of the flexible hoses are pictured below.





Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

[Mark Rinker]

Tech did a suction test while I was standing there. If fuel lines were crimped (much like a plugged filter) I believe that test would have shown the restriction.

There are clearly three injectors out of range, indicating high return rates. I failed to mention clearly that the tech wrote up his findings, and recommended replacement of all eight injectors...

Thanks for the TSB. I'll check those lines, anyway - just in case!!!

[Duramaster]

Those lines won't show much of a obstruction at idle or even at 3000 rpm's in the shop. It's more of a load thing (trailer, hill, WOT, PULL BABY PULL!)

[Mark Rinker]

Hmmm...duely noted.

I would sure like to get a fresh set of eight sprays, if possible, since the return rates indicate that as necessary, but...

The truck will certainly be up on the hoist looking into the other possiblity.

Thanks for taking the time to post. Possibly its the combination of the two.

[Mark Rinker]

(A quick update on a previous thread that I will merge with this final installment.)

Received final decision from GM customer assistance on my injector warranty claim. Denied. They were very polite, and did a fair job of collecting information on the claim, but it was also very clear that two factors weighed heavily in their decision NOT to goodwill the repairs:

Vehicle was diagnosed at 101,500 miles with high return rates on three injectors, GM tech recommended 8 new sprays.
Vehicle was not purchased new from a GM dealer, was purchased from a private party. (Two GM customer assistance reps asked me this same question, both of the Service Managers I worked with also asked as well.)Truck runs fine under 95% of daily use, but will set a P0087 low fuel rail pressure code when towing heavy and in the hills. It is repeatable, under these conditions.

If you read the entire thread , you can see how the scenario unfolded - first P0087 was assumed to be a fuel filter at 99K. Next P0087 was at 101500 and I paid to have a GM dealer diagnose and document as I was on the road.

Make sure you get any oddities DOCUMENTED by a GM dealer BEFORE the 100K cutoff...they aren't as charitable as they once were...

[Mark Rinker]

Those lines won't show much of a obstruction at idle or even at 3000 rpm's in the shop. It's more of a load thing (trailer, hill, WOT, PULL BABY PULL!)

I also inspected the supply line with the truck on a hoist, it appears fine (no obvious damage or kinks) but may replace entire supply line anyway, to rule out the possibility of an intermittent collapse... which would be nearly impossible to see unless you are under the truck when the high fuel request was happening!!!

(BTW it doesn't take WOT to trigger my P0087. It does take a fair load (12K#), warm/hot engine temps, and a reasonable climb - one that would put the %LOAD at 95% or better on the OBDII data...)

[DmaxMaverick]

Have you given thought to a lift pump setup? Certainly not a complete solution, but could edge you across the threshold causing the fault. What's JK think about it?

[Mark Rinker]

Had thought about that ... hadn't taken it any further. I still have a NIB Delco inline lift pump from the 6.5L days, would that provide enough flow?

[DmaxMaverick]

It should, at OEM to moderate fueling levels. It should work, at least, for test purposes. JK has the stuff, though (on my Christmas list). A test shouldn't be too difficult, and you wouldn't have to hard-wire or fail-safe it for the testing. If it doesn't help, you're only out some time and a little change for wiring and line coupling. If it does work, you're well ahead.

[Mark Rinker]

The p0087s were all produced at stock fueling levels, and a 6.6L doesn't use much more fuel than a 6.5L, right - if your loaded mileage is the same?

[DmaxMaverick]

Technically, correct. However, not all the fuel pumped actually finds a cylinder. Both engines use the fuel for lubricant and coolant, and return a significant portion to the tank. I don't know which returns more. I don't know which carries more heat, but my truck, even in Winter, will show a hot running fuel temp of 140°+. I've never observed the fuel temp or return rates of a 6.5 system, so I can't compare. I don't know if it even matters, one way or another. I do know several folks who have installed, and are currently running, a 6.5 OEM pump, or similar aftermarket, successfully on LB7's.

[Mark Rinker]

Started out with a fresh OEM Delco fuel filter before this trip. (The old filter lasted all winter - even through the December snap of -25F cold, without plugging. Thats a first.) Fuel level full to 1/2 tank during episodes described below, no blockage of OEM tank mounted fuel cooler/radiator.

About 1500 miles into the trip, I noticed the check engine light on. Checked and reset a 'low fuel rail pressure' code. Started watching the requested vs actual fuel rail pressures on the Edge.

Sure enough, with a stiff and gusty head wind working against the tall, shrinkwrapped boat - any hill ascended with even a medium heavy foot to maintain 60mph would predictably set the code. All of this happened while running the stock OEM tune, water temps were never over 200F, trans temps 200-220 max the whole time.

Hmmm...pulled over and looked at injector return rates at idle...nothing looked out of range, nice quiet idle, and the truck is otherwise running fine by all 'seat of the pants' measurements, until the code is set and the truck then starts running 'lopey' and low on power. When I started back at it, began watching fuel temperature. Normally it runs about 130F-150F, but today for some reason it was in the 160-170 range? All this on a sunny 75-80F spring day, Wisconsin rolling hills, with about 15K# of boat and trailer in tow...nothing out of the ordinary, really - except for the headwind.

When running the next hill, I kept my foot moderately into the throttle, watching fuel temperature...when it went past 170F and about when it hit 180F, the requested vs. actual pressures began to separate, and then *BING* the check engine light would illuminate, and the truck would start running badly. I repeated this cycle a half dozen times. There appeared to be a direct relationship between high fuel temp, and low fuel rail pressure. At one time, really pushing it - I saw fuel temperatures of 190F...that doesn't sound good!!! :(

Later that afternoon, it began to rain, the outside temperatures dropped to 60F, and the headwind and hills went away. No more codes, power felt better, and I could again easily hold 65mph with 160F fuel temps, no codes...

Whats making my fuel get so hot? Is my injection pump on its way out?

[CoyleJR]

Mark,
Have you ever crawled under your truck and cleaned your fuel cooler? About every 10k milles I spray my fuel cooler with Gunk degreaser and pressure wash it. I am always surprised by the amount of road grime that comes off of it. If your fuel cooler hasn't been cleaned recently, it could be causing high-fuel temperatures under high-power applications.

Good Luck,
John

[Mark Rinker]

No visible obstructions, but have never cleaned it. Great idea, I'll do this tomorrow!

[JohnC]

Have you ever watched the fuel temp this closely before? Maybe the temp is normal and the pump can't keep up with the thin fuel...

[DmaxMaverick]

Curious....How are you reading "fuel return rates" on the roadside? Perhaps injector balance rates or PWM, but return rates?

Anyway, start looking for the cause of the fuel temp increase. A couple possibilities come to mind....HP pump bypassing internally (failing), or failed/failing FPR/sensor. Friction = Heat. This applies to all states of matter, including liquids. Either the pump or FPR/sensor can cause this condition, which increases fuel temperature. This can also cause a snowball effect, regardless of the suspect component: Component bypasses excess fuel at high pressure -> fuel temp increases -> fuel returns to component at a lower viscosity -> fuel bypass increases (due to lower viscosity) -> fuel bypass increases fuel temp -> lower fuel viscosity and progressively increased bypass condition push the pump's ability to develop pressure -> PCM unable to maintain desired fuel pressure -> DTC set.

This condition is not likely a restriction issue. Generally, a restriction rate will decrease as viscosity decreases. This is opposite the condition you describe.

The later lower temps and less load demand doesn't help much with the diagnosis. The lower ambient temp helps prevent higher fuel temps (increases the system's ability to shed heat), and the lesser engine load reduces the fuel volume demand (less foot-feed required). The condition may still exist under this condition, but doesn't exceed the pump/FPR ability to maintain the desired fuel pressure range. Because of this, you won't likely get a dealership or garage able to duplicate the issue. You'll have to get the tech with you on the road with a load on, or on a dyno.

[Mark Rinker]

>>> Curious....How are you reading "fuel return rates" on the roadside? Perhaps injector balance rates or PWM, but return rates? >>>


Sorry, wrong terminology. Reading injector balance rates, using Edge Evolution...

Today, completed boat delivery to Walker, MN with no further codes or issues. Fuel temps averaged 130-140 all morning... (Have NOT yet cleaned the fuel cooler, but plan to.)

REQUEST FOR ASSISTANCE: To any of you that haul trailers, 5'ers, etc. and have the Edge Evolution, Predator, etc. where you can monitor fuel temps - would you give me your averages for 60mph level cruise? Please include ambiant (outside) temps during your readings. Interested to know what you are seeing...thanks in advance!

[Kennedy]

Mark,

I can't really say definitively, but in talking to my sources my gut is saying that you are seeing the injectors begin to fail in the ball seat area. This causes excess return rates and of course high fuel temps. I'm hearing more and more of this same complaint with the LBZ these days, but have yet to see one through to the end.

The big thing I am interested in is seeing a set of used injectors from a vehicle exhibiting these symptoms. Then we could test and look at whether it's an abrasive wear issue or a cavitation issue.

I have a notion it's time for another round of me harping: FILTRATION, LIFT PUMP, ADDITIVE...

[Mark Rinker]

"Gawd, with all this driving I've been doing - I hope I don't fail in the ball/seat area as well..." :eek:

JK - I switched to your tune earlier today. Going to run it for the next 5K miles at least, for the boats and destinations listed above. The next two boats are on their own trailers, with ~500 miles of empty truck/no trailer inbetween. Should be able to get a good read of unloaded cruising mileage at 65mph average.

I am starting to prepare myself for the reality that I will be buying and installing my first set of injectors for cash. Hopefully I can get through the spring push, first - and spend the money from savings, rather than throwing it on the AMEX and paying it off over the next few months. Its NEVER in the budget...

[Kennedy]

I don't know if you plan any vacation/down time, but if you do we could try to pick a pair of suspect injectors and have them tested. They'll be the hottest of the bunch. Not sure how well a guy could test with a IR thermometer if some similar device, but this should help narrow down to the worst offender(s)

[More Power]

A fuel pressure/vacuum gauge, like the one JK sells, would tell you in moments what the suction draw is, which is an indication of fuel filter life or if a problem might be with the fuel supply system (plugged sock in tank, crimped hose, etc.).

Jim

[Kennedy]

A fuel pressure/vacuum gauge, like the one JK sells, would tell you in moments what the suction draw is, which is an indication of fuel filter life or if a problem might be with the fuel supply system (plugged sock in tank, crimped hose, etc.).

Jim

I've done everything but hit him upside the head with the gauge:D so far and he still hasn't grasped the value when troubleshooting OR knowing when it's time to replace that expensive fuel filter.

[Mark Rinker]

LOL - however I don't see anything that points to a fuel system restriction, as that would be a more consistant problem.

What I am describing / experiencing happens only under very specific circumstances - i.e. heavy load + pulling hills + outside temps >75F.

Its definately fuel temp related, unless 180-190F fuel temps are considered normal...

[JohnC]

Its definately fuel temp related, unless 180-190F fuel temps are considered normal...

Or you can't get enough fuel through the system to control the temps...

Whack! ;)

[DmaxMaverick]

LOL - however I don't see anything that points to a fuel system restriction, as that would be a more consistant problem.

What I am describing / experiencing happens only under very specific circumstances - i.e. heavy load + pulling hills + outside temps >75F.

Its definately fuel temp related, unless 180-190F fuel temps are considered normal...

Realistically, no. It isn't. You're talking to the wrong end of the horse. Cause <-> Effect. Your fuel temp is an effect, not the cause. It isn't a paradox. Something is causing the results you are seeing. Elevated fuel temperature is the result of a component failure.

180-190°F is not normal. On mine (2001, but it shouldn't be too far off), the highest temp I've seen is around 160°. That was ascending Pacheco Pass (several miles of 6%) with 22K+ on, and an ambient temp of 118°F. It was as hot as it was going to get.

[Mark Rinker]

Guys, I clearly understand that the fuel is getting too hot, as a result of SOMETHING. Certainly the fuel is getting its heat transferred from engine componants - injectors and/or injection pump, its not pumped into the truck HOT! LOL

Yesterday was a big heavy boat up the North Shore of Lake Superior. All the ingredients for setting a code - except one - ambient temps were in the 40s and 50s, so no issues and fuel temps were 130s-140s, max.

Load + outside heat + hills = high fuel temps, in my case. When it hits 180/190...BING! I get the code.

[Mark Rinker]

Or you can't get enough fuel through the system to control the temps...

Whack! ;)

If I were short on fuel, I'd be short on power. Power is normal - even when turned up with JK's tune. Yesterday on a few hills, I downshifted to 4th and stood on it. My pump can maintain 24k requested and 24k actual fuel rail pressures, indefinately. Try that with a plugged/plugging filter, crimped fuel delivery hose, or plugged tank sock.

Sure looks like injectors to me, but I won't be replacing them until there are more driveability related problems than I am experiencing right now. Todays issue is the ECMs, and a theoretical one for members of TDP to digest. (No white smoke, no power loss, no knock, no oil dilution, etc...)

I am not concerned, under extreme circumstances, that my Requested and Actual FRP vary by >10%. In fact, this whole issue could be programmatically eliminated through a few tweaks with EFI-Live...there are probably many LB7 trucks out there running around with the same issue, but the ECM doesn't detect the variance and set a code. That is why an LB7 with restricted fuel filter will run until power is down, with no check engine light. LBZs with same filter restrictions will complain of low FRP...

[Mark Rinker]

I've done everything but hit him upside the head with the gauge:D so far and he still hasn't grasped the value when troubleshooting OR knowing when it's time to replace that expensive fuel filter.

Unless the gauges can be in-cab-mounted for observation during loaded, grade towing on hot days, I don't think they will be helpful in troubleshooting this problem.

Unless one of you guys wants to crawl under the hood, and go for a ride...:D

[JohnC]

If I were short on fuel, I'd be short on power.

My comment was based on the assumption that excess fuel flow is required to keep temps in check, like cooling the PMD. You may have enough fuel to produce the power, but nothing left over to carry the heat. Also, heat of "compression" likely contributes more the fuel temps than heat conducted away from engine components, but I could be wrong...

[DmaxMaverick]

I don't think it's injector(s). The possible return rate for an individual injector is minimal, and not of consequence compared to the return rate of the remainder of the system in regard to heat. If all 8 injectors were returning excess fuel to the point your fuel temp increases to the rate you are seeing, AND the rail pressure can't maintain, you would have a noticeable condition not limited to the conditions you are seeing. The PCM would be throwing a fit and you would have DTC's across the board. The injector parameters are monitored very closely. No way I can see it could return enough fuel to cause the issue and go unnoticed. It is a matter of likelihood, and I don't see it as likely. What's the likelihood of all 8 (or enough injectors) to fail in the same manner at the same time? Your odds are better at winning the lottery.

I'm still thinking pump or FRP regulator. The conditions you create may very well be pushing the fuel flow rate beyond what the system can maintain, while just under the envelope is sustainable. Pumps do not make pressure. They ONLY provide flow. A restriction is what causes pressure to develop, and pressure is maintained or limited by the amount of restriction. If the FRP or pump is bypassing, not by design, the maximum pressure attainable will be less. Fuel flow is friction, and friction is heat. At 24K PSI, this can be substantial. In any case (during your episodes), the pump is unable to develop sufficient flow to maintain desired pressure. This is either a failed pump, or a component responsible for maintain restriction. IMO, the FRP is the only component capable of flowing enough fuel to cause all the conditions you are seeing, assuming the pump is able to provide sufficient flow otherwise.

[Kennedy]

Cause-effect as Dmax Mav stated is my inclination.

It goes like this:

High loads due to head wind causes you to run deep into the tables and at a higher fuel pressure. Higher fuel pressure with ball seat issues will mean more flow and when the fuel passes it gets HOT.

The restriction gauge IS handy to verify the filter condition. This can change in one fill up or less. It will generally show at idle, but I have had guys add a hose to my gauge and clip iunder the wiper to observe.

[Kennedy]

I have fielded 4 calls from LBZ owners already today and it's not even noon.

1) Had P0087 codes and others. Replaced pump no cure. Replaced injectors and his fuel pressure issues went away. Now he's chasing boost codes. Totally stock truck

2) Has 4 Dmax trucks pulling RV's 2) 2007 LBZ, 1) 2005 LLY and 1) 2004 LB7. The 2007 LBZ's are the only ones giving grief. P0087 both trucks, sudden onset. Totally stock I believe

3) 350k and no fuel pressure problems. Running TS MP-8 (jacks fuel pressure) and called regarding different issues.

4) 2006 LLY (actually LBZ) 300k+ hauling RV's now getting P0087. Has Edge with monitor and uses it to clear codes.


I'm thinking this is still injector related (caller #1 supports this, BUT I also think this may be one of those things like the 2001 where we can do some programming changes to address this. Unfortunately not enough of the fuel psi info is available to do this at this time.

[Mark Rinker]

I recently received communication outside TDP from another 2006 LBZ owner who also hauls cargo (trailers) commercially. He had been experiencing the same P00087 low fuel rail pressure code (with limp) when the truck was fully warmed up, and while running loaded in the hills. Recently, the problem had been occuring more frequently, with less load...all symptoms identical to those I have been experiencing.

Their GM dealer had previously recommending 8 new injectors due to 'high return rates'. They did perform the physical return rate test with tubes and graduated cylinder. The truck was exhibiting no other symptoms of injector problems - no smoke, no oil dilution, etc. and had 215K miles on the factory set.

They were not convinced, were not willing to spend 4K uneccessarily, and kept on digging for answers.

Finally, another GM dealer they found on the internet had pointed out GM bulletin PIP4526 which deals with collapsing rubber fuel lines, on the draw or supply side. They replaced a section of hose per the bulletin, and have had no further issues with similar loads over similar mountains.

Hope this helps someone scratching their head over P00087 codes, with a fresh new filter and no other driveability problems. I have yet to repair my truck, but am confident this will address my issue, too. Possibly a GM tech reading this could cut and paste the contents of the bulletin in this thread.

[Kennedy]

Hmm, I wonder if a fuel system/filter restriction gauge would be helpful in diagnosing this???

[Mark Rinker]

The gauges would have to be mounted in the cab - not under the hood, so you could monitor restriction under high loaded fuel demands, while driving uphill, loaded with trailer.

Also, the lines would have to be tapped pre-filter, and then somewhere between the tank and the restriction, which in the case described was somewhere near the transmission.

Honestly, not knowing what we now know of the line collapse under demand and resulting restriction - there would have been no reason to install the gauges in these locations.

[Kennedy]

Actually for the benefit of those who may encounter a similar condition, step 1 is to measure fuel filter restriction. It is not neseccary to measure at any place other than the factory test port at this stage.



http://www.kennedydiesel.com/images/Dmax-fuel-filter-rest1.gif






Step 2 would be to measure restriction under load provided Step 1 test is passed. Now this gauge has a fixed mount to simplify operation, BUT a hose can be easily added and the gauge placed up under a windshield wiper (standard practice) while the truck is driven.

When troubleshooting something like this the first suggestion I typically make is measure filter restriction. Maybe I need to rephrase this to: Measure fuel system restriction as it seems there is an assumption that a new filter fils this operation. While a new filter CAN, it is never a given. I've seen filters load in as little as a couple hundred miles. Mdrag has not been here in a while, but he and I had this converstion some time back. Out came his restriction gauge, filter verified as loaded and problem solved until it loaded again...

[Mark Rinker]

Got it! That will really help the next time I am troubleshooting fuel related issues while hauling big oversize boats (http://www.mreboattransport.com)across the US or Canada!!!

Thanks, John!

;)

[WhiteTruck]

While rare, there is one potential area that can cause a restriction and yet not be detected by checking at the factory test port. There is a short section of line/hose that is AFTER the test port going to the injection pump. The rubber part could deteriorate internally, causing a restriction. I wouldn’t look at this until the usual causes of low rail pressure have been checked, but something to keep in mind.

[Clintv331]

For the past few weeks my truck (2006 LBZ) has been taking longer than normal time to start and has gotten worse in the past two days. Well two days ago under normal driving conditions (no load or anything) I get DTC P0087. Once the engine light was on i couldn't rev up more than 2k rpm (in park or while driving). i cleared the code with my tuner and not two seconds later it was back. at first i was thinking it was my fuel filter since it was about time to change it. Well i changed the fuel filter today and then went for a test run. I first cleared the code before taking off. once i got to not even half throttle the dtc was back. it feels like it's not getting enough fuel and is being restricted. when i got back i turned the truck off and when i started it back up it didn't take as long as it did before i changed the filter. also there is a little bit of black smoke coming out the exhaust when at idle. I have it on stock tune.

Could this be due to those hoses collapsing, bad injectors, bad fuel, or what? Can someone please give me some insight on this.

Performance mods: K&N Cold air intake, MBRP 4" turbo back exhaust, & Bullydog PMT

Thanks,
Clint

[Kennedy]

As stated earlier:

There is a simple, sure fire way to test all but the one point of restriction that White Truck mentioned. It also will save you from making premature filter changes and let you know if indeed the filter is loaded:

http://www.kennedydiesel.com/images/Dmax-fuel-filter-rest1.gif

[Kennedy]

Also watch your WIF sensors. Been seeing some of them start to leak. When an extended crank is noticed I generally recommend pumping up the primer bulb hard and this will often show a leak.

A lift pump would keep the system full of fuel and not air...

[WhiteTruck]

The information in GM PIP4526 is only helpful in the sense that it says that GM approves replacing only the hose portion of the line instead of the complete line(s) they recommended in the past. There is no new diagnostic information in it, as the supply line diagnostic is still done with a restriction gauge as JK recommends for possible causes of P0087, P0093 or P1093.

[Demilee]

Has anyone found a resolution to this problem? We are having the EXACT SAME problem. We've already replaced the hose recommended in GM PIP4526. We had that done in Austin, TX. We thought it worked until we got into some hills in Arizona and California on our drive out there.

We'd rather not spend the $4k+ on fuel injectors if that isn't the problem. Of course we have 117k miles on our 2008 3500 DRW Silverado so a warranty claim is out of the question. We only found out about the issue right after we bought the truck at 105k miles to tow our 2012 Voltage.

Any help would be appreciated!

[Mark Rinker]

I do not know of any solution to this GM programming error, other than (uneccesary) injector replacement.

Have started seeing the same issue with my 2009, starting at 125K miles. In all other ways the truck runs and performs as new.

For the $4500 injectors cost, I'll keep pushing the 'reset' button on my scan tool and clearing codes until someone programatically fixes this bug in the ECM code. When under these conditions, I keep it plugged in and resting on the passenger seat. Silly, huh? I reset the code at least ten times yesterday.

GM should be more interested, as it causes a liability issue when you reduce power to someone towing heavy on a hot day uphill...NOT good. :eek:

[greatwhite]

...
For the $4500 injectors cost, I'll keep pushing the 'reset' button on my scan tool and clearing codes until someone programatically fixes this bug in the ECM code. When under these conditions, I keep it plugged in and resting on the passenger seat. Silly, huh? I reset the code at least ten times yesterday...

You just brought back memories of driving down the road with a glitching PMD and the laptop set up on "clear codes" to stay out of limp mode....

Yeesh.

:rolleyes:

[More Power]

These rail pressure code problems come up occasionally during the hotter summer months in trucks with some miles on them - like 75,000 to 150,000 miles, while the injector data (balance rates, etc.) looks just fine when sitting in the dealer's parking lot.

The Bosch high-pressure pump appears to have a more difficult time producing the commanded rail pressure when temps are high and the fuel has thinned due to the high temperatures. Not able to meet the commanded pressure could be due to excessive fuel return flow in the injectors, pumping plungers in the Bosch CP pump not able to produce the pressure or a heat-related problem with the fuel rail pressure sensor.

With higher heat, the close fitting parts within the injectors and pumps can't generate the pressure it needs to. One way to mitigate this problem is to do something to keep fuel temperature down.

Is the return fuel cooler, located ahead of the fuel tank, clean? You can also maintain a higher level of fuel in the tank. More fuel in the tank provides a larger heat soaking reservoir. Worst case scenario - a low fuel tank and a mud caked cooler, then tow heavy in high heat. Is a larger fuel cooler or an auxiliary fuel tank (to keep the main tank full, longer) workable ideas... instead of replacing a set of out-of-warranty injectors?

If this were a 6.5, I'd suggest temporarily raising the fuel viscosity by using motor oil in a 10% mix to help determine whether the problem is due to a worn fuel injection system. Can't do this with a DOC/DPF equipped 2007+ truck. But, what about B5 - B20 bio-diesel, which is approved for the LML?

Jim

[CoyleJR]

Jim has probably hit the nail on the head. My 2006 LBZ has 180k very hard towing miles on it and has never had a problem. I keep the primary fuel tank full at all times through a gravity feed from the 100 gallon aux tank. The full tank will absorb a lot of heat from the returning fuel. Additionally, I always pressure wash the fuel cooler when I wash the truck.
So far so good.
John

[Kennedy]

After numerous calls with same issue over the years I FINALLY came across a loyal (new) customer who not only believed me, but patronized his source of free Tech advice. We sent him 8 fresh Bosch injectors and problem solved. Had the old ones tested and just as I have been saying al along, they were shot. Backflow rates were 2x stock on 5 of the 8 and 1.5x stock on the remaining 3. Problem was solved with fresh injectors.

[More Power]

After numerous calls with same issue over the years I FINALLY came across a loyal (new) customer who not only believed me, but patronized his source of free Tech advice. We sent him 8 fresh Bosch injectors and problem solved. Had the old ones tested and just as I have been saying al along, they were shot. Backflow rates were 2x stock on 5 of the 8 and 1.5x stock on the remaining 3. Problem was solved with fresh injectors.

Worn injectors are certainly a possibility. No question there. There is a specific fuel return flow test that the dealership could perform, but they could not duplicate the hot-hot conditions under which the codes set.

What would injector retailers and installers do if new injectors didn't help? This problem could also be due to the CP pump/FPR.

What if... cooler fuel allowed the engine to remain code free?

[Kennedy]

Maybe we could get Mark Rinker to do a water mist injection on his fuel cooler and see if that helps.

[Mark Rinker]

Interesting timing on this last comment...85F day in Kentucky I75 mountains today and reset the code too many times. Filled the tank and expected it to slow down, but it remained pretty consistant.

Was thinking about a cheap experiment with doubling the fuel cooler size. Misting would also be interesting.

Coyles experience with additional filtration and high fuel capacity sure sounds encouraging, especially if the towing is heavy, hot, and uphill. Maybe he'll chime in to tell us more about what is typical loads and such are...max loads/max hills?

[Mark Rinker]

After numerous calls with same issue over the years I FINALLY came across a loyal (new) customer who not only believed me, but patronized his source of free Tech advice. We sent him 8 fresh Bosch injectors and problem solved. Had the old ones tested and just as I have been saying al along, they were shot. Backflow rates were 2x stock on 5 of the 8 and 1.5x stock on the remaining 3. Problem was solved with fresh injectors.

Tell ya what John, until my sprays won't spray anymore I am pushing the button ;)

How much for a custom tune that eliminates the P0087 altogether? Seems to me that its a 'bug' in the ECM, not a hard part problem, although I am sure you are right that fresh sprays would correct it - for another 125K miles or so...

[Mark Rinker]

My hypothesis is that a larger fuel cooler, and/or fuel cooler misting would reduce the number of occurances, to the extent that it could keep fuel temps at or below 160F as observed earlier in this thread. I don't think it would eliminate the codes being set, for how I thrash these trucks in the late summer running mountains and tall/wide boats.

Clearly its a symptom of high gallon injectors - miles has nothing to do with it, its the # gallons of fuel through them that wears them out.

My 2006 and now my 2009, doing exactly the same work with exactly the. same trailer with exactly the same driver and exactly the same loads started to fail at EXACTLY THE SAME MILEAGE.

Suprised? Nope.

I am on a mission to program around this, and keep treating fuel and running rail cleaner to see how long I can keep the injector tips happy. Then I'll probably take the 5K and trade on a 2011. But thats just me, and this is a business truck, which is sort of like a carpenters hammer. They wear out, I get a new one.

Ever wonder why JK hasn't rolled up his sleeves in the last few YEARS we've known about this, and delivered a clean solution to the programming problem GM created?

Hmmmm.... ;)

[Kennedy]

Tell ya what John, until my sprays won't spray anymore I am pushing the button ;)

How much for a custom tune that eliminates the P0087 altogether? Seems to me that its a 'bug' in the ECM, not a hard part problem, although I am sure you are right that fresh sprays would correct it - for another 125K miles or so...

It's not that easy. In fact I am not sure that it could be done entirely. The issue is available tables may not list everything. Fresh injectors, filtration, lift pump, and additive would be interesting.



My hypothesis is that a larger fuel cooler, and/or fuel cooler misting would reduce the number of occurances, to the extent that it could keep fuel temps at or below 160F as observed earlier in this thread. I don't think it would eliminate the codes being set, for how I thrash these trucks in the late summer running mountains and tall/wide boats.

Clearly its a symptom of high gallon injectors - miles has nothing to do with it, its the # gallons of fuel through them that wears them out.

My 2006 and now my 2009, doing exactly the same work with exactly the. same trailer with exactly the same driver and exactly the same loads started to fail at EXACTLY THE SAME MILEAGE.

Suprised? Nope.

I am on a mission to program around this, and keep treating fuel and running rail cleaner to see how long I can keep the injector tips happy. Then I'll probably take the 5K and trade on a 2011. But thats just me, and this is a business truck, which is sort of like a carpenters hammer. They wear out, I get a new one.

Ever wonder why JK hasn't rolled up his sleeves in the last few YEARS we've known about this, and delivered a clean solution to the programming problem GM created?

Hmmmm.... ;)

The LBZ would have been easier. Again I get the calls, tell them what I have observed and never hear back. I have not had opportunity to even ride in one that has had this issue. The LBZ I think could be fixed more easily, but when I did try a mail order deal the guy said that what I did made it worse...

[More Power]

Maybe we could get Mark Rinker to do a water mist injection on his fuel cooler and see if that helps.

I don't think everyone gets the reference.... ;) I think I still have the spray bottles I used in a TIC story a few years ago... :D

On a more serious note, we all know that the 6.5 community has suffered for a long-long time by dealer diagnoses that pronounced the DS4 electronic fuel injection pump as needing to be replaced for just about any sort of engine running problem. In some of those cases, it was the pump, and in many others it wasn't. Good troubleshooting eliminates the other possibilities before jumping to the most expensive solution - like changing head gaskets instead of looking for a spun impeller on a water pump.

On the other hand, if a prognosticator is so absolutely positively convinced of his diagnosis, it should come with a money back guarantee. That would be a big convincing selling point... ;)

On another note, I saw your pic & stuff in Diesel Power mag. Good job!

Jim

[Mark Rinker]

Interesting observation from yesterday...

Loading a large boat in sweltering temps yesterday near Ackworth, GA. So hot that I left the truck running with AC on so I could take few breaks to avoid heat overload...

After I left the marina, loaded and hit I-75, immediately started getting the P00087 codes. Reset 3-4 times in the first 15 minutes and then it started slowing down in frequency...

So, under only AC accessory load idling either the high return rates heated up 3/4 of a tank of fuel (doubtful) - or high underhood temps alone are enough to cause the low fuel rail pressure code. THIS IS A VERY TELLING OBSERVATION OF THE PROBLEM, IMO.


Also it appears that the problem has not come up on LML trucks - so possibly GM changed their programming?

[Mark Rinker]

Maybe we could get Mark Rinker to do a water mist injection on his fuel cooler and see if that helps.

No, I didn't get it - but should have considering the source.


>>> After numerous calls with same issue over the years I FINALLY came across a loyal (new) customer who not only believed me, but patronized his source of free Tech advice. >>>

JK - I am not going to buy new injectors. I am not going to buy your Mega filter. I am not going to buy your vaccuum gauges, either. No cases of FPPF. It has nothing to do with believing you. Its also not because I am simple, or stubborn. It is a simple cost/benefit decision based on how I use and freqently trade my power units for my business. Period.

Over the years, I've run your LB7 and LBZ tunes with great results. I've purchased 6.5 and Duramax lift pumps, two sets of boost/EGT gauges, two sets of shocks, an EGR block-off plate, a case of FPPF and an hour of dyno tuning. This is what I can think of, off the top of my head. Q: Who is the loyal customer?



“You can make more friends in two months by becoming interested in other people than you can in two years by trying to get other people interested in you.” ― Dale Carnegie (http://www.goodreads.com/author/show/3317.Dale_Carnegie), How to Win Friends & Influence People (http://www.goodreads.com/work/quotes/2370171)





The same applies to sales, JK. Get interested in the P00087 limp problem programmatically and I'll be your customer...again. I have tons of real world experience that can be tapped into, if you stop selling, and start listening.

[Kennedy]

The same applies to sales, JK. Get interested in the P00087 limp problem programmatically and I'll be your customer...again. I have tons of real world experience that can be tapped into, if you stop selling, and start listening.



Someone was always going to swing by with a local load and his 2006 LBZ.
Get interested yourself and keep in mind it may take HOURS and I need to get back home. I am also a bit less optimistic abouth finding the LMM issue as readily as the LBZ based on table availability.

I listen, I sell, and more importantly I fix problems and create solutions to prevent them. Heck I called in a favor to have a used set of injectors tested and then reported my findings here.

[More Power]

On a perhaps related subject....

I spoke with a midwest fuel injection shop owner recently about "white smoke at idle". The conversation began by him asking me what I knew about using ATF as a diesel fuel treatment. I told him that I didn't have a problem with it, and that the additional lubricity should, in theory, help with longevity. I also added that every fuel injection and fuel treatment company rep I spoke with a while back condemned using ATF - for obscure and not easily understood reasons.

He (Matthew) told me that their shop had changed quite a few Duramax injector sets through the years for the white smoke problem. Since they also rebuild the injectors, their shop guy started looking at the parts, and noticed nearly all of the injectors removed for a white smoke problem contained a residue buildup inside the nozzle tip. There was no particular wear or other problem with the injector, just a buildup of residue that affected the nozzle sealing.

The ATF question arose because the shop has a few customers who routinely add ATF to their fuel. One of them had to have a set of injectors replaced for a different reason, and their tech guy found no such residue inside the nozzles. The only difference was the use of ATF as a fuel treatment. Apparently, ATF in the fuel keeps the injectors clean.

I asked Matthew if the traditional fuel treatments are keeping the injectors nozzles clean, and he told me that they're not seeing a difference. Interestingly, I spoke with Mark Rinker recently about a concentrated fuel system cleaning procedure some dealers have begun using at dealerships, to help solve some of the problems experienced by Duramax owners.

Food for thought....

Jim

[cabletech]

I don't know how smart, safe or good for the engine this would be!!!!

There is a limp mode torque limiting table that can be changed with EFILive. It limits torque above 2000 rpm. Changing it would not stop the CEL or fix the problem, but may stop you from having to clear codes all the time.

Food for thought.

Jay

[Kennedy]

Without going into great detail, when the LBZ injectors that I mentoned previously were being tested it was discovered that they got worse when cleaned of varnish or with a new nozzle installed.


I prefer to fix the problem not hide it by circumventing safety limits. Also there are undoubtedly many tables not present in the EFI tool making it difficult to find all paths to this particular limp mode.

[Mark Rinker]

I don't know how smart, safe or good for the engine this would be!!!!

There is a limp mode torque limiting table that can be changed with EFILive. It limits torque above 2000 rpm. Changing it would not stop the CEL or fix the problem, but may stop you from having to clear codes all the time.

Food for thought.

Jay

Sounds like an interesting idea. I am willing to test it and pay for the development time necessary. My goal is simple...swap ECMs until I get to the end of the road (tip/nozzle problems) on this set. Past experience says this will be about 40k miles down the road. I have a core ECM from my 2006.

[More Power]

Without going into great detail, when the LBZ injectors that I mentoned previously were being tested it was discovered that they got worse when cleaned of varnish or with a new nozzle installed.


I prefer to fix the problem not hide it by circumventing safety limits. Also there are undoubtedly many tables not present in the EFI tool making it difficult to find all paths to this particular limp mode.

Can the cause of high fuel return be identified? Do you know what component parts are the cause? Thanks,

Jim

[Kennedy]

Ball seat erosion is evident and likely (speculative) due to dirt or debris.


Lift pump, filtration, quality additive

FWIW responding to an earlier post: Just because I sell something doesn't mean I push as an agenda for my own betterment. I'm a firm believer in the old addage ounce of prevention = pound of cure. I'd rather solve a problem than fix one any day...

[Kennedy]

Yesterday I had a local call me with a 2007 LBZ exhibiting same P0087 symptoms. Had him remove the POS plastic fuel filter and stop by. System restriction good. Pump tested good ramping psi at idle.

I made a couple of tuning changes to allow more RPM and TQ in limp mode (not convinced that this will work) and a single table change to his stock tune and we'll see what happens. Also set him up with a monitor to watch pressure, temp, and rate.

This is a 70k "rebuilder" that is supposed to be legit miles. He hauls with it pretty much daily, but it's not yet at a point where it will act up on demand. Takes the better part of the day and maybe a hot soak to get it to act up. Thankfully it's local so if it persists I can do a ride along and hopefully find a work around.

[cabletech]

There are 2 tables for limp mode (torque & pulse width) and 1 torque table for when a DTC is set. I have not had a problem with my LBZ, but was going to try this if it happens.

Jay

[Kennedy]

I really don't care to disable protective functions on non race vehicles. It's best to tune the issue directly. That way if there is a real issue teh protective functions take ove. That said, I have had experiences with Race vehicles, all limp modes removed, DTC P0087 disabled in the tune file and it still set P0087.

Not everything within EFI is as it appears and it is far from a complete set of tables.

[cabletech]

Winols would probably show all the tables. In order to change the way the ecm handles the under pressure condition, you would have to change the os itself. EFILive will never do that. You may be able to make changes with a hex editor, but that's way over my head.

Jay

[Kennedy]

I will continue to test and develop a "work around" but instinct tells me that operating under load in these conditions will probably hasten the demise of the injectors in question by elevating return fuel temps even further.

For those facing this condition, you can take the truck in to a dealer and have the return rates tested (I've been told $300) but I'm afraid you'll just be spending money to learn something that we already know...

[Mark Rinker]

The ideal solution would be to create a 'Custom Tune' with the P00087 programming fix, and make it widely available via the Diablosport / Predator handheld tuner.

Why?


No swapping ECMs
Most people encountering this error will be outside warranty anyway
Handheld gives ability to read/reset codes if P00087 persists, or as others arise
Easy to 'return to stock' if this method of overriding factory protection doesn't work for this user
It could even be stacked on a mild tow/economy tune...made available for wide distribution. I'd gladly give it away via my website to people having problems with this programming error by GM. It appears to be resolved in the factory LML programming - or maybe nobody has rolled up enough miles yet to see the problem arising...


Anyone experienced with creating Diablosport Custom Tunes?

[Kennedy]

Sending out a device with my local customer tomorrow. Five test files loaded plus ability to read and clear codes.

[Mark Rinker]

JK - I am headed empty to Johnsburg, IL tomorrow (Tuesday 7/31) afternoon, loading 31' 12K# boat for return to Minneapolis. Not sure that I'll have enough boat, heat or hills to trigger a P00087, but likely if over 85f and I run a bit deeper into the throttle than normal.

Let me know if you want me to swing by, I'll leave a bit earlier.

[Kennedy]

If you find that you are in position to make this happen at will, and have time shoot me an email with ETA.

Bear in mind we'll probably need to run up to I 29 and drive/stop tune repeat and may take several attempts.

I did not hear back from my local guy, but I think he was out with a load today.

[Kennedy]

I guess more importantly, can you deviate from planned route or are you oversize and restricted?

[Mark Rinker]

Someone was always going to swing by with a local load and his 2006 LBZ.
Get interested yourself and keep in mind it may take HOURS and I need to get back home. I am also a bit less optimistic abouth finding the LMM issue as readily as the LBZ based on table availability.

I listen, I sell, and more importantly I fix problems and create solutions to prevent them. Heck I called in a favor to have a used set of injectors tested and then reported my findings here.

JK - Thanks for making yourself available this week for me to swing by. As fate would have it, there was a lengthy delay at the marina, followed by a low hanging telephone wire about two miles down the road that wasted alot of time in my day.

On the way home across WI, I only had two codes set, even though the temperatures were in the 90s. Both were shortly after getting underway, after sitting still and idling.

Heat soak and hot fuel is my hypothesis.


We'll keep trying to connect and test this thing!

[Kennedy]

Still testing here. Tune 3 reportedly went all day yesterday without tripping. I told tester that I'd like to have him try (within reason) to get this code to set so we'll see what happens.

Too early to tell, too many variables so we need to keep on testing.

How high were/are your fuel temps reaching?

Thinking we may try twin lift pump setup to help the CP3 and potentially increase circulation to potentially help with pump temps

[Kennedy]

More testing/validation required, but it appears as though tune #3 is doing what it is supposed to. Rail psi's were holding at or near desired and no P0087. Fuel temp pushed up even higher as I had expected.

We need to get lift pumps on this truck to see what impact we can have on fuel temps.

[Mark Rinker]

Any chance of making this programming available via the Diablosport/Predator handheld as a custom tune?

If no - is there any way to reflash the stock ECM with this fix and a mild tow/economy bump.

Reason for asking is this truck is probably going down the road this fall, as part my my relocation to Seattle. I'd like to sell it with a solution for the P00087, that doesn't require or assume much knowledge of the end buyer - i.e. whomever gets it at the auto auction after its traded in.

[Kennedy]

There's no way that I'd be working with any other "generic" hardware. This will be something that I wil incorporate into my Kennedy Custom programming. The next issue though is will the bump in power make the code set again. Still a lot of questions, but it looks like we're making progress...

[Kennedy]

Test subject stopped in today and I verified which tune it was that worked. Planning to do lift pumps soon, possibly next week. I also have him cleaning fuel cooler. It looks pretty grungy at a glance.

[Kennedy]

I recently did a performance tune for LMM and added the same correction. Customer made trip and tells me that he easily would have tripped 12 or more times on this type of run. He thought that he was free and clear, but managed to trip it once just out of the blue. Considering the added demand/load of the tuning this isn't bad. We are taking a wait and see approach and will consider more tweaking if the issue persists.

[Mark Rinker]

Unless that guy is hauling in the southwest, my guess is he will have more issues next summer when higher temps return. Ambient temps which contribute to high fuel temps are a big part of this issue.

I am finishing up a 3000 mile trip today, with a heavy wide boat and through terrain that would have tripped the P00087 many times last summer. So far only two codes set, and that was running hard uphill with a low tank of fuel. The only difference? About 30-40 degrees less ambient fall temps.

This issue is best solved via programming tweaks, but it is clearly a combination of all that has been discussed, including:


High mile or high fuel volume injectors (i.e. always towing)
Heavy loaded towing, usually compounded by hills
High fuel temps, caused by excessive return rates, low fuel level in tank, poor fuel cooling or flow, etc.
If I'm still hauling boats next summer I will buy your finished product, if it can be warranted to solve yproblem. However, my goal is to be in Seattle driving a 2012 ZL1 Camaro (http://www.chevrolet.com/camaro-zl1-sports-car.html)by then, although I may be driving my daughters Jetta if I can't find anyone to buy my biz...we'll see which happens first!


Mark @ www.MREBoatTransport.com (http://www.MREBoatTransport.com)

[Kennedy]

This trip was made during conditions that would have normally caused the limp numerous times. I'm a bit late in reporting.

Customer is well aware that he's likely delaying the inevitable and that there are NO GUARANTEES and I make this clear in my Tech Tip, but for now if it helps minimize the instances plus increasing the capabilities if in limp mode it's a win-win for most.

Again no guarantees, BUT a willingness to adjust and tweak to work around the issue as needed.

[dually2002]

I have been curious if diesel fuel is formulated for use in a high pressure application like the Dmax. Most of the fuel the pump picks up is by-passed back to the tank so fuel is constantly recirculating and besides picking up heat from the engine it also adds heat from being under pressure. I wonder if a fan located to blow on the fuel heat exchanger would help. Also the fuel constantly be re-circulated and the ultra low sulphur content of the fuel might be reducing lubricating properties of the fuel to the point that it harms the injectors.

[getinrad]

I've been a victim of this same issue now for a month. We replaced all of the stock fuel lines, installed an airdog and completely bypassed the stock filter housing, and I still get this same message when I lay on the throttle or when towing heavy loads. I have 2007.5. Could it be the FPRV?

[Mark Rinker]

How many miles on your injectors? What other filtration are you using? Lift pump?

Potentially anything that could cause the system to not deliver actual fuel rail pressures as commanded by the ECM can be to blame. I have personally never seen unloaded/high acceleration set this code.

In my cases its always towing heavy in the hills with heat as an exaggerating factor - i.e. HOT fuel.

[Mark Rinker]

Update: Interesting observation today while running same route from Grasonville, MD through mountains of MD, WV, PA...the route that tripped the P00087 countless times in July with a SeaRay 310 (12000#) in tow at 85F outside temps.

Today was a Chaparral 350l, tipping the scales closer to 15K#, but the outside temps ranged from 14f to an icy 9f.

You guessed it...no matter how hard I drove the truck (extended 4th gear, 3000rpm charges up 8% grades to maintain 55mph, passing semis with their flashers on one after another) I never set the code all day.

So...it may be a worn injector situation that causes the high return rates, that heats up fuel, that contributes to low rail pressures...BUT...the biggest cause is

HOT FUEL. (period)

Somebody make a bigger undercarriage mounted fuel cooler with fan assist and I think you'd narrow the window considerably, if not eliminate it entirely, throughout the lifespan of the injectors. I have 155K on my originals and they are running as strong as day one. Not touching a thing, certainly not for a pesky code where I can push a button and 'fix' the programming error. Its certainly not worth installing new injectors to fix, at least not in my case which is towing heavy on hot days in the hills.

I know...how about we programmatically correct this bug in the ECM? :D

[Kennedy]

I still have guys calling me with this issue in the winter months here. Odd, but some are still having issues. I've sent out some revised tuning and made sure that they understood that things may change when it warms up so we'd readjust then. Only time (and hot weather) will tell.

The big fan fuel cooler idea may help, but you can't get below ambient in the tank and I think on a hot summer day she'll just heat right back up again as the temps are coming from the journey across teh valley to the CP3, the pressurization within the CP3 and probably to an even greater extent from the release/backflow at the injector.

[Maxdout1]

Im having the same problem on a 06. I put 8 new gm injectors in and still having the same problem. It only does it at wot and when its warm. Pump at idle you can ramp it up to 24000 psi and hold it all day. when it warms up it will command 26000 and drop to 12000

[Demilee]

Today we brought our truck to a guy that specializes in fuel line issues here in Austin, TX. We finally bought a device to reset the code back in Sept so we haven't been wasting time waiting for limp mode to clear on its own. That seemed like major progress at the time.

However, the whole issue seems to be getting worse and becoming more of a pain to reset while driving, especially in traffic. We feel that towing 12a + ton toy hauler and dealing with these limp mode issues is going to become unsafe at some point. The code is now setting at lower temps than before (low 60s) and while going up minor but long inclines. In a nutshell the issue seems to be getting worse.

Once we get our official diagnosis I will post back here.

[Kennedy]

Im having the same problem on a 06. I put 8 new gm injectors in and still having the same problem. It only does it at wot and when its warm. Pump at idle you can ramp it up to 24000 psi and hold it all day. when it warms up it will command 26000 and drop to 12000


I can only speculate that you may benefit from some tweaking in the tuning. This is ASSUMING thatyou are not running a plastic bodied fuel filter and have no excessive restriction.

I'd probably start by lift pump supply pressure first.

[CoyleJR]

I often tow 24k lbs in the Arizona mountains at 115f and my 185k mile LBZ truck has never set P0087 code or gone into limp mode. I have a 100 gallon aux fuel tank and a gravity/check ball feed into the 34 gallon primary fuel tank. This system keeps the 34 gallon truck tank full at all times. I think the full tank of fuel absorbs a lot of the heat from the hot return line fuel which helps keep the entire fuel system cool. Additionally, I pressure wash the fuel cooler under the truck bed about every 30-60 days.

I would suggest to anyone setting the P0087 code to pressure wash your fuel cooler and keep as much fuel as possible in your fuel tank when towing. It won't cost anything and it seems to be working for on my truck. I could just be lucky and my truck could start acting up tomorrow.

Good Luck
John

[Mark Rinker]

Im having the same problem on a 06. I put 8 new gm injectors in and still having the same problem. It only does it at wot and when its warm. Pump at idle you can ramp it up to 24000 psi and hold it all day. when it warms up it will command 26000 and drop to 12000

This supports my theory that its about HOT fuel, as much or more than return rates. That should have been solved with new sprays. How many miles on the truck when it first occurred?

[Mark Rinker]

I often tow 24k lbs in the Arizona mountains at 115f and my 185k mile LBZ truck has never set P0087 code or gone into limp mode. I have a 100 gallon aux fuel tank and a gravity/check ball feed into the 34 gallon primary fuel tank. This system keeps the 34 gallon truck tank full at all times. I think the full tank of fuel absorbs a lot of the heat from the hot return line fuel which helps keep the entire fuel system cool. Additionally, I pressure wash the fuel cooler under the truck bed about every 30-60 days.

I would suggest to anyone setting the P0087 code to pressure wash your fuel cooler and keep as much fuel as possible in your fuel tank when towing. It won't cost anything and it seems to be working for on my truck. I could just be lucky and my truck could start acting up tomorrow.

Good Luck
John

x2 on the HOT fuel theory. I assume these are your original factory sprays, John?

[CoyleJR]

Mark,

Yes my truck is running the original (from the factory) injectors. The only things that are not original on the truck are the drive shaft carrier bearing, one glow plug #8, and tires and brakes. It is the best truck I have ever owned. Good luck when you relocate.

John

[GM Customer Service]

Today we brought our truck to a guy that specializes in fuel line issues here in Austin, TX. We finally bought a device to reset the code back in Sept so we haven't been wasting time waiting for limp mode to clear on its own. That seemed like major progress at the time.

However, the whole issue seems to be getting worse and becoming more of a pain to reset while driving, especially in traffic. We feel that towing 12a + ton toy hauler and dealing with these limp mode issues is going to become unsafe at some point. The code is now setting at lower temps than before (low 60s) and while going up minor but long inclines. In a nutshell the issue seems to be getting worse.

Once we get our official diagnosis I will post back here.

Please let us know any updates you may have! We are here at your convenience.

Brandon
GM Customer Service

[Demilee]

First of all, I'd like to thank Mr. Rinker for suggesting we purchase a scanner to clear our codes while driving. We were so sick of waiting on the side of the road for the limp mode to clear on it's own. We finally got one last summer. BTW the code only did clear on it's own as trans. temps got lower. Maybe that can info can help someone out? Maybe that has to do with the FUEL temps?!?!?!

Anyway, I'm reporting back regarding the service we had done in Austin for the P0087 codes we are getting... We were hopeful that the guy at the shop was correct when he thought that it was a valve and seal (used to diagnose fuel pressures?). It ran about $90 to replace that, he noticed it was broken just after opening the hood of the truck. He said if that didn't work he recommended "Kill'Em". (We have not tried that since we were going to be towing in a few days and wanted to see if the valve replacement worked.) He tested the fuel injectors and said they all looked fine. (Even though we were told at a Chevy dealership in Pensacola, FL in 2011 that we needed 4 replaced!)

So, our trip from Austin, TX to Tucson, AZ started out great! We thought that we had found our FRP Savior. Nope... We left early in the AM, when the temps were low. My story is quite consistant with Mr. Rinker's you see, high outdoor temps and under load with hills pops P0087. We ended up stopping to take a nap and let the temps cool outside. The cool desert night is our friend with this FRP issue. :)

Interestingly, we got a code of p2002 a two times within our 1.5 days of travel to Tucson. Also, got a p2563 code as well. I understand these are both emissions codes, likely unrelated? If no, maybe that is another clue?

With the 85k miles we have put on this truck driving around the U.S. for the past one and a half years, UNDER LOAD half of the time, I've also come to believe this is a FUEL TEMP issue. This supports Rinker's theory and has been mine for awhile as well. I do 95% of the driving when we're towing. It's like I know the truck personally now, and I know when it's going to pull the dreaded p0087 code.

Since I am a "dumb" girl at least I had enough sense to ask the last mechanic about where the dang fuel cooler was so I can try to clean that next. I'd rather not pull out the bottle of "Kill'Em" we bought. That stuff is lethal, I can't believe you can even buy it over the counter. (I'm a bit of a klutz and I'm afraid it will get on me.)

I'll be checking back again soon after some more troubleshooting. I welcome any feedback. Cheers!
-Demi

2008 Silverado - 3500 HD DRW (189k miles - symptoms since ~115k - purchased at 105k)
*We've had the GM bulletin PIP4526 collapsing fuel line issue addressed already.
*Our fifth-wheel is 11-12.5 tons. (arrived 21k from the manuf.)

[cabletech]

Demi

Is your sig correct that you 5th wheel is 21k lbs dry? If so that is way over the towing capacity of your truck and contributing to (or causing) your hot fuel problem.

Jay

[JohnC]

The fuel cooler is a small radiator under the truck just forward of the fuel tank.

[CoyleJR]

Demi,

I agree with Cabletech, if your trailer is 21k # you do NOT have enough truck to pull it or stop it. The total weight of your truck and trailer would be 29k to 31k #. Your truck appears to be similar to my 2006, CC, Dually and it is rated to haul (truck & trailer) 24k #. I think you just added the truck weight to the trailer weight in your signature (I hope). If your truck and trailer weigh around 24k # you should be OK. If you are actually running a total combined weight around 30k # you have far exceeded the design limits of the truck and that is likely the cause of your problem.

Last week I posted a suggestion to pressure wash the fuel cooler and to run as much fuel in your tank as possible and see if you were still setting the P0087 code. To wash the fuel cooler go to a self operated car wash. Then lay on the ground and spray the one foot square radiator looking thing mounted under the bed behind the drivers side of the cab. When you think it is clean spray it some more. I always am impressed by the amount of dirt that is left on my driveway when I clean the cooler. Additionally, experiment by topping off your fuel tank when it gets down to 3/4 full capacity for a travel day or two and see if it helps with the P0087 code problem. On a diesel motor part of the fuel that is pumped to the motor returns hot to the fuel tank and the full fuel tank will help to absorb the heat from the returning fuel.

I hope things start working a little better for you with the truck. You indicated you were in the Tucson area and I would suggest that you camp at the Kartchner caverns state park (I10 & SR 90) and take day trips to Tombstone and Bisbee. The caverns are great, Tombstone is fun and my family really loved the mining car ride into a 100 year old mine in Bisbee.

If you do weigh around 30k # be very careful in the Az mountains. I am very cautious and I have still had my brakes smoking on these hills.

Good luck & safe travels
John

[Demilee]

I was wrong about the info on the dry weight. Apparently it's only ~14,500. So that is not the issue. Sorry about that guys, I was getting incorrect info from somewhere.

>>"Last week I posted a suggestion to pressure wash the fuel cooler and to run as much fuel in your tank as possible and see if you were still setting the P0087 code. To wash the fuel cooler go to a self operated car wash. Then lay on the ground and spray the one foot square radiator looking thing mounted under the bed behind the drivers side of the cab. When you think it is clean spray it some more. I always am impressed by the amount of dirt that is left on my driveway when I clean the cooler. Additionally, experiment by topping off your fuel tank when it gets down to 3/4 full capacity for a travel day or two and see if it helps with the P0087 code problem. On a diesel motor part of the fuel that is pumped to the motor returns hot to the fuel tank and the full fuel tank will help to absorb the heat from the returning fuel."

Totally agree with the hot fuel issue. We added "Kill'Em" to the tank today per the mechanic's suggestion. I don't expect anything to happen. We are staying in Tucson for a few weeks so if we don't have any issues with fungus, etc. in the fuel lines then we plan to clean the fuel cooler REALLY WELL as you suggested. We're doing one thing at a time so we can be sure what action fixed the issue. We leave Tucson at the end of the month so I'll be reporting back then to let everyone know how cleaning the fuel cooler helped on our drive to Malibu, CA.

Thanks, D

2008 Silverado - 3500 HD DRW (189k miles - symptoms since ~115k - purchased at 105k)
*We've had the GM bulletin PIP4526 collapsing fuel line issue addressed already.
*Towing a 2012 Dutchman Voltage 3900 (7.25 tons dry)

[Jeff Paxton]

First off, thanks to everyone who contributed to this discussion. I believe it has at least some good workarounds, and likely, the real solution to the problem. I am towing a 14,500# res style 5th wheel purchased last April from Southern California. Towed it home through the Rockies and over Loveland Pass with no problems. It was still cold in the Rockies and snowing much of the trip, but warm on the flat desert of southern California/Nevada. Then in August, back over Loveland for camping, and home over Berthoud Pass. The truck did warm up climbing Loveland that time, but no codes, just needed coolant.

My truck is down right now. I am in DesMoines trying to get home to CO. We left CO in March, for work at Perry Nuclear Plant outage in NE Ohio. After outage it was off to PA for a vacation with family. The trip out there went smoothly with the late/cool spring.

We left PA June 9th. Climbing a good hill mid afternoon in western PA, I got my first check engine/limp mode and the temp gauge indicating the the coolant was warming up. Googled up the manual limp mode reset and got back on the road in an hour. Happened again after 40mins, climbing again. Did the manual reset, and decided to look for a stealership. Pulled into the next town which didn't even have a dealer, or a parts house, but did have 2 bay diesel shop for big rigs, and a mechanic who drove a '07 Dmax classic with a programmer. He came over, pulled the 87 code, reset, and said "Must've gotten dirty fuel, get a fuel filter". Off to napa. It clouded up, started to rain, got to napa, installed new filter. Made it to northern MI the next evening to visit more family, without any more trouble. Problem solved?

We left MI on the 15th stopping in Minooka, Il for the night, still no problems. Headed west in the morning hitting the hills in eastern Iowa by early afternoon. Yup, code/limp/pull over/manual reset at Coralville. Pulled off thinking "that was some really bad diesel, if it crapped up another filter that fast." Went to O'reilly's, picked up AC Delco filter, installed and back on the road in little over an hour. Hit the road and noticed check engine was OFF?? Hmmm? Drove a while, got another check engine/limp/pull over/manual reset and each time the coolant temp has climbed, once near red line. It's not the filter, I need a mechanic.

Got it into DesMoines, set up the camper at Adventureland, and took the truck to Bob Brown GMC the next morning. They did not want to hear the details. Their attitude... "Just leave, we'll figure it out and let you know." I get a call..."You need new HP fuel pump, two fuel rails, and 8 new injectors. A ceramic ball valve in the pump is failing and ruined the entire fuel system after the pump. And oh, you have a head gasket leak that we can fix while we're in there for just over $12k." Yea, I'll be getting a second opinion, and if that's the truth, a new motor. They quoted me just over $19k for the new motor. Next stop, West Side Diesel Repair.

They confirmed the HP pump diagnosis, dispelled the leaking head gasket, and agreed to replace the pump, coolant system chemical flush, fuel system clean/flush, and agreed that without one single symptom associated with injector failure presenting, fix those if/when symptoms say to.

Got the truck back first thing Friday morning. Hit the road at 11. Made it 20 mins west of DesMoines (and I was pushing/testing) and we were turning back after another manual reset. Waiting until Monday for them to resume but I am pushing the collapsed fuel line angle, and once they fix that and/or whatever else they come up with, I will be heading to a car wash to do the fuel cooler clean you all recommend, and trying again. Keep you posted....

[CoyleJR]

Jeff,
First let me welcome you to the Diesel Page. I am sorry to hear about the troubles with your truck. It appears that you have read the posts about the P0087 code and know that there are a lot of theories about the cause. If you do find a definite cause please post it for others to draw help from.
It would help if you posted detailed specifics about your truck. The year, motor, any programers, mods like larger tires or exhaust.

It is clear that there are a lot of people with the P0087 problem, because over 30k people have read this thread. Does anyone at GM customer service on line reading this have any ideas? I am not beating up on GMCS it just seems that this is a big problem with the Duramax in hot weather. The only thing that gets more hits on the DP seems to be the injector failures on the LB7 Dmax. GM should be doing research and putting out service bulletins.

Good luck and keep us posted
John

[Jeff Paxton]

Thanks for the welcome.

I own a 2006 GMC 2500HD, LLY tune, and aside from airbags to level it, it is bone stock. I bought the truck Aug of 2011 with 189k miles. Traveling for work to the east and south, it now has 228k. I run 265's rather than the 245's but this is insignificant and it is absolutely ferocious... when not towing!

I will keep the forum posted of the outcome whether it is resolved or not. The thought of trading it is crossing my mind, but for what? They ALL have their own problems. Don't want to drive a Freightliner...

[rapidoxidationman]

Making sure the fuel cooler is clean is a good step, and the AllData site also suggests making sure the fuel heater (if equipped) is not stuck in the ON position.

[Jeff Paxton]

What is the process for determining it is eqiupped and checking?

[DmaxMaverick]

What is the process for determining it is eqiupped and checking?

It has one, unless it's been removed. Check for battery voltage at the top electrical connector on the filter assy. If necessary, it can be disconnected without any drama.

[GM Customer Service]

Hi Jeff,

I am sorry to hear about these difficulties you are experiencing. I would be happy to assist, but I do recommend that repairs be made at a certified GM dealership as they are our eyes and ears on the field. If you could private message me your name, address, phone number, VIN, and current vehicle mileage I can start the process for you in getting the vehicle issues resolved. Thank you!

Jessica
GM Customer Care


First off, thanks to everyone who contributed to this discussion. I believe it has at least some good workarounds, and likely, the real solution to the problem. I am towing a 14,500# res style 5th wheel purchased last April from Southern California. Towed it home through the Rockies and over Loveland Pass with no problems. It was still cold in the Rockies and snowing much of the trip, but warm on the flat desert of southern California/Nevada. Then in August, back over Loveland for camping, and home over Berthoud Pass. The truck did warm up climbing Loveland that time, but no codes, just needed coolant.

My truck is down right now. I am in DesMoines trying to get home to CO. We left CO in March, for work at Perry Nuclear Plant outage in NE Ohio. After outage it was off to PA for a vacation with family. The trip out there went smoothly with the late/cool spring.

We left PA June 9th. Climbing a good hill mid afternoon in western PA, I got my first check engine/limp mode and the temp gauge indicating the the coolant was warming up. Googled up the manual limp mode reset and got back on the road in an hour. Happened again after 40mins, climbing again. Did the manual reset, and decided to look for a stealership. Pulled into the next town which didn't even have a dealer, or a parts house, but did have 2 bay diesel shop for big rigs, and a mechanic who drove a '07 Dmax classic with a programmer. He came over, pulled the 87 code, reset, and said "Must've gotten dirty fuel, get a fuel filter". Off to napa. It clouded up, started to rain, got to napa, installed new filter. Made it to northern MI the next evening to visit more family, without any more trouble. Problem solved?

We left MI on the 15th stopping in Minooka, Il for the night, still no problems. Headed west in the morning hitting the hills in eastern Iowa by early afternoon. Yup, code/limp/pull over/manual reset at Coralville. Pulled off thinking "that was some really bad diesel, if it crapped up another filter that fast." Went to O'reilly's, picked up AC Delco filter, installed and back on the road in little over an hour. Hit the road and noticed check engine was OFF?? Hmmm? Drove a while, got another check engine/limp/pull over/manual reset and each time the coolant temp has climbed, once near red line. It's not the filter, I need a mechanic.

Got it into DesMoines, set up the camper at Adventureland, and took the truck to Bob Brown GMC the next morning. They did not want to hear the details. Their attitude... "Just leave, we'll figure it out and let you know." I get a call..."You need new HP fuel pump, two fuel rails, and 8 new injectors. A ceramic ball valve in the pump is failing and ruined the entire fuel system after the pump. And oh, you have a head gasket leak that we can fix while we're in there for just over $12k." Yea, I'll be getting a second opinion, and if that's the truth, a new motor. They quoted me just over $19k for the new motor. Next stop, West Side Diesel Repair.

They confirmed the HP pump diagnosis, dispelled the leaking head gasket, and agreed to replace the pump, coolant system chemical flush, fuel system clean/flush, and agreed that without one single symptom associated with injector failure presenting, fix those if/when symptoms say to.

Got the truck back first thing Friday morning. Hit the road at 11. Made it 20 mins west of DesMoines (and I was pushing/testing) and we were turning back after another manual reset. Waiting until Monday for them to resume but I am pushing the collapsed fuel line angle, and once they fix that and/or whatever else they come up with, I will be heading to a car wash to do the fuel cooler clean you all recommend, and trying again. Keep you posted....

[Jeff Paxton]

Jessica, I do not have private message privilege's yet due to being too new a member of the forum. Maybe you can send one to me and I can reply?

[GM Customer Service]

Hi Jeff!

It looks like I am unable to send you one as well. Sorry about that! If you would like to send me an e-mail through socialmedia@gm.com and label the subject line "Attention: Jessica G" we can correspond that way. Thank you!

Jessica
GM Customer Care


Jessica, I do not have private message privilege's yet due to being too new a member of the forum. Maybe you can send one to me and I can reply?

[Demilee]

I doubt going to a GM or any other dealership is going to help, like Jessica from GM suggests. No offense. I have to say I've had 2 Chevy dealerships tell me to get new injectors. HOWEVER, two other Chevy dealerships say no and so did 3 separate diesel engine techs who own their own business. Can't leave it up to a huge corporation to solve an issue on trucks that are all past their warranty date. If that were true we wouldn't be posting here right now about this issue... Like another poster said this is one of the most checked threads on the forum.

Anyway, I apologize to everyone that I never posted back about our truck issues. No they are still not resolved. I tried cleaning off the fuel cooler. Still not sure about how to disconnect a fuel heater like DmaxMaverick suggests. I personally would need some more detailed steps on how to do that.

Jeff, you said

Waiting until Monday for them to resume but I am pushing the collapsed fuel line angle, and once they fix that and/or whatever else they come up with, I will be heading to a car wash to do the fuel cooler clean you all recommend, and trying again.
I'd do the collapsed fuel line repair anyway but don't hold your breath on that working long term. It's still a good idea. I think the whole repair for that only cost us about $100.

I'm actually thinking of getting suped up fuel cooler after all the symptoms we've had. Anyone think that this sounds like a good idea to try out? Someone on this forum that works on diesels named "DieselTech" seems to have the answer. ---> Add another fuel lift and another fuel cooler.
http://www.dmaxcentral.com/forum/showthread.php?t=5358

At this point we are just dealing with the problem. We baby our truck when towing, never use the cruise, make use of the down hills to get up the next hill and clear codes as needed. We plan to drive a good 3-4 hours when starting out on any extended trip and then we stop off for breakfast or lunch somewhere (and we are VERY leisurely about it) to get the truck to cool down as much as possible. This seems to help a lot so far. We also get fuel just before leaving instead of getting it the night before. Maybe this is helping with the fuel temps?

Jeff please let us know if anything works for you.

-Demi

2008 Silverado - 3500 HD DRW (198k miles - symptoms since ~115k - purchased at 105k)
*We've had the GM bulletin PIP4526 collapsing fuel line issue addressed already
*Already tried washing off fuel cooler
*Towing a 2012 Dutchman Voltage 3900 (7.25 tons dry)

[DmaxMaverick]

To keep it simple:

There are 2 wire harness sets to the filter assembly. The lower is the WIF (Water In Fuel) sensor, and the upper is the fuel heater. Follow the upper wires from the filter assy to the connector. Disconnect the connector if you want/need to disconnect the heater. The PCM controls the heater, but doesn't monitor it. The PCM only sends voltage to the heater, but doesn't monitor feedback, so if it isn't connected/working, it won't know (or care).

[Demilee]

To keep it simple:

There are 2 wire harness sets to the filter assembly. The lower is the WIF (Water In Fuel) sensor, and the upper is the fuel heater. Follow the upper wires from the filter assy to the connector. Disconnect the connector if you want/need to disconnect the heater. The PCM controls the heater, but doesn't monitor it. The PCM only sends voltage to the heater, but doesn't monitor feedback, so if it isn't connected/working, it won't know (or care).

Great! I know exactly which one you mean now. Thanks! :)

-Demi

[Jeff Paxton]

Just got the call from the repair shop. They said, "We did an injector balance test and the numbers are all over the place indicating you need injectors." Of course, not being a diesel tech, I can't make sense of this. All I can do is look at obvious symptoms that present when injectors are bad. I don't remember all of them at the moment, but It starts easily, idles like a purring kitten, doesn't smoke, and has power out the wazoo when not hooked up to a load. Thoughts anyone? Will this cause a starvation for fuel under load when downshifting up a hill? I am still leaning toward fuel lines as a logical reason. But when they call me with a parts quote, I want to either tell them do the fuel lines, or just tell them I'm coming to get it because I am not doing injectors regardless. The truck isn't worth that kind of expense.

Edit to add: he said "the balance rates are ranging from -.4 to 1.7 or 9 or something..." From what I am reading, anything inside of +/-4 is acceptable so...?

Just got off the phone again with the quote. $7k+ for new fuel rails and injectors. I said I am not throwing more good money after bad and I will be picking it up to limp it home. I asked specifically what the values were on the balance test... Now he said -.8 to 1.5. I didn't argue that this acceptable, what's the point? They don't want to mess with the fuel line collapse. I may pursue it a little more once I get home, with my dealership, but I will let you all know the outcome. I may just sell the whole rig and forget it.

[More Power]

Question to JK....

Why is the LBZ and LMM more likely to produce a P0087 than an LB7 or LLY (at least that seems to be the case...)?

Jim

[CoyleJR]

Jeff,
If you don't have a scanner that will clear the codes while driving you may want to consider purchasing one. You could have a loooong drive back to Co if you can't easily clear the codes. It may help if you try keeping the fuel tank as near full as possible, traveling in the evening or night and keeping your speed around 60mph. I personally think the biggest factor with the P0087 code problem is hot fuel. You seldom hear of anyone showing a P0087 code in the winter months.
Good luck
John

[Jeff Paxton]

Coyle, I don't have a scanner but I think I can go easy enough to make it the 2 hours to the flats west of Omaha. We'll be leaving early in the morn, and fronts have moving through cooling things down. It doesn't take too long to clear a code manually, but it does if it is the actual "cool down" from parking that benefits it the most. I thoroughly pressure washed the fuel cooler as well. I have always gone 60 when towing the rig just for ease of handling, but I will do as Demilee and use the downhill to gain on the uphill if need be so... I think you are correct on the 87 code, have NEVER had one when it was cool/cold. And I will definitely be keeping the tank 1/2 full+. I will disconnect the fuel heater as well per DmaxMaverick's instructions. Anyway, I will let the forum know how it goes.

[Demilee]

Just got the call from the repair shop. They said, "We did an injector balance test and the numbers are all over the place indicating you need injectors." Of course, not being a diesel tech, I can't make sense of this. All I can do is look at obvious symptoms that present when injectors are bad. I don't remember all of them at the moment, but It starts easily, idles like a purring kitten, doesn't smoke, and has power out the wazoo when not hooked up to a load. Thoughts anyone? Will this cause a starvation for fuel under load when downshifting up a hill? I am still leaning toward fuel lines as a logical reason. But when they call me with a parts quote, I want to either tell them do the fuel lines, or just tell them I'm coming to get it because I am not doing injectors regardless. The truck isn't worth that kind of expense.

Edit to add: he said "the balance rates are ranging from -.4 to 1.7 or 9 or something..." From what I am reading, anything inside of +/-4 is acceptable so...?

Just got off the phone again with the quote. $7k+ for new fuel rails and injectors. I said I am not throwing more good money after bad and I will be picking it up to limp it home. I asked specifically what the values were on the balance test... Now he said -.8 to 1.5. I didn't argue that this acceptable, what's the point? They don't want to mess with the fuel line collapse. I may pursue it a little more once I get home, with my dealership, but I will let you all know the outcome. I may just sell the whole rig and forget it.

Yea, I believe it was Mark Rinkler from this thread that got all new injectors and it didn't help at all.

[Demilee]

I asked this before in another post. I'm actually thinking of getting souped up fuel cooler after all the symptoms we've had. Anyone think that this sounds like a good idea to try out?

Someone on this forum that works on diesels named "DieselTech" seems to have the answer. ---> Add another fuel lift and another fuel cooler.
http://www.dmaxcentral.com/forum/showthread.php?t=5358

Anyone have thoughts/opinions on this?

[Demilee]

Coyle, I don't have a scanner but I think I can go easy enough to make it the 2 hours to the flats west of Omaha. We'll be leaving early in the morn, and fronts have moving through cooling things down. It doesn't take too long to clear a code manually, but it does if it is the actual "cool down" from parking that benefits it the most. I thoroughly pressure washed the fuel cooler as well. I have always gone 60 when towing the rig just for ease of handling, but I will do as Demilee and use the downhill to gain on the uphill if need be so... I think you are correct on the 87 code, have NEVER had one when it was cool/cold. And I will definitely be keeping the tank 1/2 full+. I will disconnect the fuel heater as well per DmaxMaverick's instructions. Anyway, I will let the forum know how it goes.

Yes, we found that going 55 to 60 is best too. We were going 65 in some states. That pops the code more often. Makes sense of course. We're in CA now so can't go over 55 anyway! :) But I def have went over the speed limit here going downhill to get up hills. I figure I am more of a hazard going 30 in limp mode than going 5-10 miles over the speed limit.

Good luck Jeff!

[CoyleJR]

I don't think anyone has ever posted a problem with a P0087 code on a medium duty GM truck(4500, 5500) with a D/A. Do they have something different from the standard pickup? How large is the fuel cooler on a medium duty GM truck? Are they also having trouble with the P0087 code and no one is posting it? Just some things concerning the P0087 code to think about.
John

[Jeff Paxton]

I can't wait for the answer to that, Coyle, since that is what I'm looking at doing.
Anyway, update: We have made it to council bluffs after a later than planned start due to lack of sleep/nerves. but still got out at a decent time under cloudy skies, 78 degrees. The skies have cleared and temp has climbed to 83. I have NOT used tow/haul to avoid advancing the shift down since limp always comes at 5th to 4th. Been running in 6th mostly but did shift from 6th to 5th three times. On the second one, I did get a check engine,but no limp! It may be a different code though, I will let you all know. The coolant temp is not fluctuating as much, it did touch 215 twice.

[More Power]

Yea, I believe it was Mark Rinkler from this thread that got all new injectors and it didn't help at all.

It's my understanding that new injectors almost always solve the problem - once the other more routine possibilities have been eliminated.

Another-larger fuel cooler could work, as does an auxiliary fuel tank. In either case, it's a bandaid that might allow a set of injectors to reach design life.

I wonder if B5 or B20 bio-diesel helps or hurts in these situations because of how fuel viscosity is affected.

Jim

[Jeff Paxton]

Well, thought we were in the good after making council bluffs/Omaha. Got a limp between Omaha and Lincoln. Just got another and we are barely out of Lincoln. After stopping to eat, came out to a pretty good wind. It's a head wind and it's killing me

[CoyleJR]

Jim,
That is a very good thought about bio-diesel. I stopped using it years ago when I realized that it hurt my fuel mileage and it cost more than regular diesel. I also have an auxiliary tank that keeps my primary tank full at all times. My 190k mile, LBZ truck has never shown a P0087 code. Friday will be a test, the temperature is predicted to be 120 and I will be going east over the mountains from Phoenix Az. The total weight will be near 24k lbs and if the truck doesn't show P0087 code it never will.
John

[Jeff Paxton]

Best of luck Coyle.

We made it. Ran 60-65 for 14 hours with about 4 for stopping to eat, fuel, and the two limps. There were no more full blown limp modes after the second west of Lincoln, until I was home climbing the last hill. Out on the flat, running 1600 rpms won't trigger it so Nebraska was great. Going into the dealership tomorrow, I'll post any news. Stressful day, I'm beat.

[Kennedy]

I just tuned a couple more locally for this issue. One has been running great since the tune. He hauls cattle (mostly calves) so he's all over the state and can be quite heavy. Only back once for CEL that was for a bad plug. The other has not been out and worked yet.

As MP suggested, the addition of a bit of Bio may help the viscosity similar to the old motor oil in fuel trick to temporarily fix DB2 hot start issues.

Lift pump, secondary filtration, and quality additive are what I prescribe for prevention.

[More Power]

Lift pump, secondary filtration, and quality additive are what I prescribe for prevention.

Why does it appear that the LBZ/LMM are more often affected by a P0087 than the LB7/LLY?

Thanks

[Kennedy]

Why does it appear that the LBZ/LMM are more often affected by a P0087 than the LB7/LLY?

Thanks


If I had to guess I would say that it has to do with the way that Bosch did the programming on the later models as well as possibly the direct-to injector control of the later models. Also probably emissions related.

Earlier models of course were Delphi and controlled indirectly through the FICM.

[Jeff Paxton]

Kennedy, what about this question from Coyle? I would like to consider these on my trade if it is true.


I don't think anyone has ever posted a problem with a P0087 code on a medium duty GM truck(4500, 5500) with a D/A. Do they have something different from the standard pickup? How large is the fuel cooler on a medium duty GM truck? Are they also having trouble with the P0087 code and no one is posting it? Just some things concerning the P0087 code to think about.
John

[Kennedy]

If anything the med duty trucks are worse. The relationship between the engine and tank in both elevation and distance being greater plus the overall weight makes the pressure differential inside versus outside the lines greater to move fuel. In laymen's terms that have to suck harder to get the fuel to flow from the tank to the pump.

[Mark Rinker]

Yea, I believe it was Mark Rinkler from this thread that got all new injectors and it didn't help at all.

Hello all. For clarification, I never replaced the injectors on my 2009 K3500, the last Duramax I sold with the sale of my business. I included the Diablosport Predator LBZ/LMM handheld programmer (with code reset capability) with the truck and told the new owner all about the P00087 situation.

I had the same issues with the 2006 truck that preceded the 2009...becoming more frequent as the trucks neared 100K miles in service.



Good luck with your work-arounds.

[Jeff Paxton]

Update: Per GM customer care request, took the diesel tech for a ride-a-long today towing the camper to try and trigger limp mode while he had his computer plugged in. Was fortunate to get it to limp twice. The temp was 88 degrees. He was frantically writing down info most of the time. So now I will wait to see what they come up with after they hash it out. Will keep you all posted.

[Mark Rinker]

Hopefully they modify the ECM code to widen the acceptable gap between requested and actual fuel rail pressure, in relation to fuel temperatures.

Problem solved.

Its a programming error!!!

[Kennedy]

Widening the range will likely not happen. High pressure is what gets them atomization and makes emissions. The key is to get the ECM the info it needs so it can command the pump to deliver more volume to compensate for increased return flows and maintain proper psi.

This also plays into economy and explains why many find that adding a lift pump improves response and overall fuel economy slightly. It's just easier for the ECM to maintain steady rail psi.

[GMADVISORMT]

Going to try cleaning the fuel cooler on a 2008 here at our dealership. I think that's a great idea. We have had a lot of trucks here with that same code. Most of them just need a fuel filter, though the last one had an injection pump that came apart... That was spendy. I'll let ya'll know what we find on this one, its a 2008 with 190,000 on it. original sprays.

Also for my introduction... GM service advisor here, I am running a 2002 Chevy 2500HD 8.1/Ally... Gas guzzler but pulling machine. Thanks for the great forum

[More Power]

Going to try cleaning the fuel cooler on a 2008 here at our dealership. I think that's a great idea. We have had a lot of trucks here with that same code. Most of them just need a fuel filter, though the last one had an injection pump that came apart... That was spendy. I'll let ya'll know what we find on this one, its a 2008 with 190,000 on it. original sprays.

Also for my introduction... GM service advisor here, I am running a 2002 Chevy 2500HD 8.1/Ally... Gas guzzler but pulling machine. Thanks for the great forum

Welcome to the board! Your input is appreciated. The code P0087 is an emerging problem for the LBZ/LMM. Jim

[GMADVISORMT]

Welcome to the board! Your input is appreciated. The code P0087 is an emerging problem for the LBZ/LMM. Jim

Its been quite the issue here in Montana. Lots of guys pulling a lot of weight. I have two more coming in later this week for the same issue. I wish we could just reprogram these things and change the tolerances-no can do.

We recommend fuel filters every year or every 15,000 miles. That sure seems to help with many of the fuel issues on these trucks. I have seen collapsed fuel lines ONE time.

I'd recommend starting with the filter, and then spraying off that cooler. Though come to think of it, I have a gentleman that has a Duramax that we actually pulled/measured fuel return and it was high on 3/4 injectors on one side. That pretty much confirmed the issue was related to injectors on that pickup. Its a pain of a test, but worthwhile.

Hollar at me if you need assistance with bulletins, etc.

[Jeff Paxton]

Final update: This will come as no surprise to anyone, but after being delayed on trading the truck off for 2 months in order to fulfill GM's requests for hoop jumping, they say they will do nothing. After starting here on the boards with "Jessica", then being passed to "Dustin", who passed it to "April", who then finally passed it to another gal who I could barely understand so I didn't get her name, to give the "We are sure sorry for wasting your value-less time just to tell you we won't do anything about it" speech... But we're sure sorry, we're really sorry, so sorry Mr. Paxton ad nauseum.
She said, "April put in the request for cost assistance for replacing the injectors, and it was denied." I said, "So the diesel tech at my dealership concluded after analyzing the data from the ride-a-long that it was for sure injectors?" Her reply... "Um, er, a, yeah!" So after thanking her for wasting enough of my time that I will have no time to work a deal on a trade and am now forced to pull the rig back to the east coast for work with this truck in a few days, I called my dealership. I said, "Did Brent (the diesel tech) talk to GM yet?" The reply, "NOBODY from here has talked to anybody at GM about your truck yet!" I said, "Funny, they just told me Brent said it was the injectors and that they wouldn't help with new ones." The reply, "Brent says he would like to try the FPRV. But he didn't say ANYTHING about injectors." They lied.
The same as everybody here, I never expected them to do anything to begin with, but they contacted me! Insisting that I do this and that, saying that they would do SOMETHING about it. I should have told them "No thanks" from the get-go, but I am not an impolite person. It's the lying at the end that really irks me, jerking me around for what? Their entertainment?
Going to try try the FPRV replacement. I will post if it works.

[Kennedy]

The reply, "Brent says he would like to try the FPRV. But he didn't say ANYTHING about injectors." Going to try try the FPRV replacement. I will post if it works.


It's not going to make a damn bit of difference. Try a bottle test first, BUT see if Brent can follow simple logic:

1) The system makes adequate pressure (160mpa) at light loads.

2) The FPRV is a simple analog valve to protect from overpressure.

Acknowledging these facts, how could the relief valve start dumping at 16,000 psi under load then recover and work fine at light loads.

I've seen these valves fail. They don't necessarily fail, they weaken. They weaken from use as they were NOT designed to see any actual use. They are there to prevent any potential mishaps and are set well enough above the highest commanded psi. The problem is that once they weaken they flat line at pretty much the same psi.

We do a shimmed valve that bumps the pressure up higher yet. This should not be necessary, but some feel the need. The reason they activate is the lack of a lift pump and/or restricted supply causes severe pressure cycling where the pump overcorrects and the pressure spikes beyond the set point.

[More Power]

.....It's the lying at the end that really irks me, jerking me around for what? Their entertainment?
Going to try try the FPRV replacement. I will post if it works.

Not to make excuses for GM, but we all need to remember that GM is a large company - a large bureaucracy. Without a "service order number" to reference, to keep everyone on the same page, who said what will certainly get lost as the discussion gets moved around.

If a service order number was cut for this problem, and the discussion about who said what still got lost, then there's no excuse. Jim

[Jeff Paxton]

Not sure if it's the same thing, but what "Dustin" referred to as a case number was given to me and I was instructed to refer to the number in my correspondence with GM service people both on my end and in Detroit. The number was 71-1198579870

Kennedy: I think I misspoke concerning what Brent wanted to try, though maybe it makes no difference. I said incorrectly about the fprv, Brent wanted to replace the fuel pressure regulator. ??? Anyway, I replaced the fprv. The computer senses that mileage is improved, though I think it was simply that the relief valve had partially stuck open and this fuel was not actually being burned, but rather dumped during what the computer sensed as lowered economy. It is averaging 1.8 mpg's "better", closer to what I normally got before all this began, according to the computers sensors. It had definitely weakened as the limp mode became easier to trigger throughout. I think the regulator is still a valuable possibility. If the fprv has no effect, I should know soon enough and will post, but cooling temps may play a part in delaying a limp until we return to higher temps next summer. In any event, I intend to keep the board posted of any results I get, good or bad.

[dougmac]

Hello! I am new to this form. I found this a very interesting thread. I am a diesel mechanic and have my own perspective on this problem..

The first thing I check when I have a rail pressure fault on a common rail fuel system is the injector spill-back. Excessive spill back appears to be the problem most of you are facing. I see it mentioned but not being addressed. I imagine that is due to the cost of the injector replacement.

Common rail systems return very little fuel back to the tank under normal conditions. On a Duramax, if every injector was at the the maximum allowable spill-back, at an idle you would only be returning 100ml per minute to the tank.

Excessive spill back causes the fuel demand to exceed the high pressure pump's capacity. As the fuel temp increases and the fuel viscosity decreases the spill-back will increase.

I also theorize, as the spill-back increases the excessive returning hot fuel introduces more heat into the fuel tank further exasperating the problem by elevating the temperature of the fuel in the tank.

From my perspective, you may be able to mask the problem with program tweaks and beefed up coolers but in the end to really solve the issue, you probably need to address the injector problem.

Doug

[Kennedy]

Hello! I am new to this form. I found this a very interesting thread. I am a diesel mechanic and have my own perspective on this problem..

The first thing I check when I have a rail pressure fault on a common rail fuel system is the injector spill-back. Excessive spill back appears to be the problem most of you are facing. I see it mentioned but not being addressed. I imagine that is due to the cost of the injector replacement.

Common rail systems return very little fuel back to the tank under normal conditions. On a Duramax, if every injector was at the the maximum allowable spill-back, at an idle you would only be returning 100ml per minute to the tank.

Excessive spill back causes the fuel demand to exceed the high pressure pump's capacity. As the fuel temp increases and the fuel viscosity decreases the spill-back will increase.

I also theorize, as the spill-back increases the excessive returning hot fuel introduces more heat into the fuel tank further exasperating the problem by elevating the temperature of the fuel in the tank.

From my perspective, you may be able to mask the problem with program tweaks and beefed up coolers but in the end to really solve the issue, you probably need to address the injector problem.

Doug


Comments above are quite accurate and what I've been saying all along, but I will add that I have several trucks running with program tweaks that saved the $5-7k cost of replacing injectors.

[dougmac]

Comments above are quite accurate and what I've been saying all along, but I will add that I have several trucks running with program tweaks that saved the $5-7k cost of replacing injectors.

I am guessing the program tweaks prevent the PCM from reporting the low rail pressure condition and keep the engine from de-rating. The pump can only move so much fuel. Under a heavy load, it is still is not able to keep up with the demand of the injectors with the excessive leakage. The low rail pressure condition is still present.

As long as the performance is not affected significantly and you are saving thousands of dollars, I completely understand why folks would go that route rather than fixing the actual problem.

Doug

[Kennedy]

I am guessing the program tweaks prevent the PCM from reporting the low rail pressure condition and keep the engine from de-rating. The pump can only move so much fuel. Under a heavy load, it is still is not able to keep up with the demand of the injectors with the excessive leakage. The low rail pressure condition is still present.

As long as the performance is not affected significantly and you are saving thousands of dollars, I completely understand why folks would go that route rather than fixing the actual problem.

Doug


Actually that is not the case. The P0087 is still reported and I do not simply widen the parameters. My adjustments are made to the pump control in an effort to provide the increased flow necessary to remain on target.

I do alter the limp mode somewhat to make it more useable though as the way it is now can be pretty hairy in traffic on a grade.

[dougmac]

Actually that is not the case. The P0087 is still reported and I do not simply widen the parameters. My adjustments are made to the pump control in an effort to provide the increased flow necessary to remain on target.

I do alter the limp mode somewhat to make it more useable though as the way it is now can be pretty hairy in traffic on a grade.

When a low rail pressure code presents itself the FICM has already commanded the high pressure fuel pump to 100% duty cycle to attain the requested fuel pressure. The code is set when it cannot maintain the requested fuel pressure and falls 2,176 psi below that requested fuel pressure.

I am not sure I understand.....

I don't see how it is possible to increase the "flow" beyond what the pump is capable of at 100% duty cycle. At 100% duty cycle, it is at its mechanical limit.... no matter what the programming is, the FICM can only send 100% duty cycle to the Fuel Pressure Regulator there is nothing beyond that. At that point the pump is maxed out... it cannot physically flow beyond its mechanical displacement....

[rapidoxidationman]

http://i368.photobucket.com/albums/oo124/hellojoycekittyness/deer-eating-popcorn.gif

[Kennedy]

FICM? What FICM?

I guess it's just magic or something like that. ;)

I'm not going to get into the detail, but it has to do with expected flow which is a calculated value based on what fresh injectors are expected to deliver and return. My theory is that once the return rate plus the delivery rate exceeds the expected flow by some apparent value the ECM needs to make excessive corrections, gets upset and quits trying. This explains why it is load sensitive. Same general operating pressures, but increased delivery.

[dougmac]

I very respectfully disagree with your theory,

As a course of troubleshooting for low rail pressure problems, I generally like to observe the desired rail pressure, the actual rail pressure and the pressure regulator duty cycle. I have yet to see a situation where I had rail pressure reading below desired and the pump was not commanded to 100%. Your experience may be different but it seem illogical that the the pump would be commanded below 100% when the ecm was detecting rail pressure below the requested value.

That's my story and I am sticking to it ..... ;)

[Kennedy]

Every Dmax that I have ever seen operated within a window of about 45%-5% in fact the programming control tables for the regulator have hard coded limits of 95% and 5%.

Maybe the FICM altered the signals :rolleyes:

[dougmac]

So you are saying the ecm is not capable of commanding the pump to its maximum output? I am not buying it... not for one second ....

[DmaxMaverick]

Just curious....

Is the FICM relevant to the model year(s) in this discussion?

[Kennedy]

Just curious....

Is the FICM relevant to the model year(s) in this discussion?

No it absolutely is not.

[dougmac]

Just curious....

Is the FICM relevant to the model year(s) in this discussion?

Its not... if you didn't catch on, its a dig at me...

I guess asking how you use a software change to get more volume out of a pump that is already working at is capacity poses a problem.....

[Kennedy]

When a low rail pressure code presents itself the FICM has already commanded the high pressure fuel pump to 100% duty cycle to attain the requested fuel pressure. The code is set when it cannot maintain the requested fuel pressure and falls 2,176 psi below that requested fuel pressure.

I am not sure I understand.....

I don't see how it is possible to increase the "flow" beyond what the pump is capable of at 100% duty cycle. At 100% duty cycle, it is at its mechanical limit.... no matter what the programming is, the FICM can only send 100% duty cycle to the Fuel Pressure Regulator there is nothing beyond that. At that point the pump is maxed out... it cannot physically flow beyond its mechanical displacement....


For clarification there is no FICM as mentioned above.

There is no 100% duty cycle to the pump. Additionally, 100% duty cycle would be regulator completely closed and 0% duty cycle would be wide open.

[dougmac]

For clarification there is no FICM as mentioned above.

There is no 100% duty cycle to the pump. Additionally, 100% duty cycle would be regulator completely closed and 0% duty cycle would be wide open.

Ok... I concede ... I am dumber than you..

Now explain in simple terms that a dumb guy can understand. How you use a software change to get more volume out of a pump that is already working at is capacity?

[DmaxMaverick]

Its not... if you didn't catch on, its a dig at me...

I guess asking how you use a software change to get more volume out of a pump that is already working at is capacity poses a problem.....

I don't think it was a dig at you.

Anyway, I think you are limiting the scope to only what is available within the allowable envelope of the vehicle calibration, and discounting the physical capability of the HP pump. Technically, a true "100%" duty cycle of the pump would likely see it destroyed in a very short period (unless #2 Diesel were infinitely compressible, but it's not, so....). The pump itself is "dumb", only varying its output according to the flow control, which is controlled by PCM commands, according to sensory data input and programmed demands. The operating envelope of the pump is determined by the calibration parameters, not the physical capability of the pump. Demanding a 100% duty cycle of the pump is only commanding the full duty cycle allowed by the calibration, and not, necessarily, the full capability of the pump (otherwise, the upper threshold of the pump's performance would have to be identical from pump to pump, vehicle to vehicle, under every conceivable condition). It's comprehensive, according to dozens of channels of sensory data. The PCM doesn't know, and doesn't care, what the physical limitation of the pump is (unless it's incapable of answering mechanical demands, not according to calibration parameter demands). The FPR/FRPR is limited only by the vapor, AKA: the PCM, via the vehicle calibration, sensory data, emission system control, and powertrain performance demands. Moving the operating envelope (range) of the pump performance sensory data, such as John is suggesting, is nothing more than that. Simple, and perhaps a band-aid fix, but it works often enough to make it a viable solution, if only temporary. The alternative is to pony up a few grand for a repair that may not be necessary for years to come. If it doesn't work, the only loss is a little time.

[dougmac]

Generally the high pressure pump does not produce its full volume because it is regulated by a pulse width modulated solenoid. It will increase and decrease volume as the demand changes. The only time you would see it at full volume is when it has fallen below the commanded pressure.

If it cannot maintain the requested pressure the system will log a code and derate the engine.

[DmaxMaverick]

Generally the high pressure pump does not produce its full volume because it is regulated by a pulse width modulated solenoid. It will increase and decrease volume as the demand changes. The only time you would see it at full volume is when it has fallen below the commanded pressure.

If it cannot maintain the requested pressure the system will log a code and derate the engine.

If that's the case, then why is it 9 generations of Duramax calibrations commanding 95% duty cycle all produce very different pressure and volume parameters? If you are correct, then all of them at "maximum duty" would all produce the exact same pressure. As you suggest, it's the PWM that limits the pump output, not its absolute physical capability. The problem isn't the pump, but the other end of the fuel rail. The root cause of this discussion is the sensory data failing to report acceptable fuel usage accountability, for whatever reason. Addressing a functioning pump is talking to the wrong end of the horse. This was never a pump problem. Although the problem is almost always the injectors, it was never as prevalent until the calibration parameters were changed. Same pump, same injector performance, same fuel pressure and volume regulation means. So, why wouldn't it be reasonable that a PCM calibration adjustment just might correct the condition in many cases?

The injectors in question are suffering the same exact failures as previous and later series. The component interoperability hasn't changed. The only difference is when the PCM perceives them to have failed, and will demand correction (SES lamp, limp mode, etc.). The pump isn't failing to perform just because the PCM says it is, and neither is the remaining fuel system components. No more than they have with any other series.

[Kennedy]

Ok... I concede ... I am dumber than you..

Now explain in simple terms that a dumb guy can understand. How you use a software change to get more volume out of a pump that is already working at is capacity?


I did not say that you are dumb. What I am pointing out is that you have made 2 factually incorrect statements and likely a third

1) There is no FICM

2) The pump flow at 100% duty cycle is theoretically 0

3) So how do you know the pump command is really giving all it can when the DTC is set?


The way I see it for those who face this condition there are 6 options:

1) Replace the injectors
2) ECM programing
3) Ignore the problem and reset the code on the fly as MRE did for quite some time
4) Spend hundreds if not thousands in diagnostics and parts changing everything short of the injectors because they cost most.
5)Sell or trade the truck
6) Step into in Mr Peabody's WABAC machine and go back to the day the truck was delivered. Add a lift pump, secondary filtration, and quality additive to every ounce of fuel that you burn.



FWIW the WABAC machine pre-dates me by a significant number of years bet here it is:

http://upload.wikimedia.org/wikipedia/en/3/3f/Waybackmachine3.png

[rapidoxidationman]

This is an interesting conversation to me and I've been following it closely. I'm hoping the new guy won't get frustrated and quit visiting this forum cuz it does sound like he knows a bit about the dmax and could be a valuable asset here - if he can take the initiation...

I'm trying to understand just how the HPFP and related system works, given the info that's been presented by both sides of the discussion. Hopefully someone will confirm or deny what is presently my understanding:

The high pressure fuel pump is driven by the engine (cam, chain, gear, it doesn't matter). It is mechanical and directly connected so its ability to pump fuel is directly related to the engine speed.

The fuel pressure regulator does the control side of things, is electronically controlled, and does the bidding of the ECM according to load, RPM's, and requested pressures to make the injectors work properly. It has the ability to be fully closed (delivering 100% of the pressure the pump is able to put out but very low volume) or it can be fully open (essentially dropping the pump output pressure to zero but with high volume in layman's terms) but the normal range of operation is - what - between 5% and 50%?

So when the injectors (or whatever failing component) have too much free flow and the regulator has to go beyond that normal range of operation the computer gets pissed off, sets a code, and goes into limp mode.

Kennedy's solution tweaks the "normal range of operation" to something that is technically out of the engineer's specs, but allows normal operation albeit with higher flows from the regulator to compensate for worn parts.


How'd I do?

[DmaxMaverick]

This is an interesting conversation to me and I've been following it closely. I'm hoping the new guy won't get frustrated and quit visiting this forum cuz it does sound like he knows a bit about the dmax and could be a valuable asset here - if he can take the initiation...


We value the input of anyone willing to engage, with something to offer (or nothing to offer, for that matter). This is especially true of the technicians actually working in the field. We, TDP, need to do the best we can to ensure everyone is on the same page, so to speak, especially when unorthodox methods are being implemented. A $5K repair is not always the immediate solution, such as in this case.


I'm trying to understand just how the HPFP and related system works, given the info that's been presented by both sides of the discussion. Hopefully someone will confirm or deny what is presently my understanding:

The high pressure fuel pump is driven by the engine (cam, chain, gear, it doesn't matter). It is mechanical and directly connected so its ability to pump fuel is directly related to the engine speed.

The fuel pressure regulator does the control side of things, is electronically controlled, and does the bidding of the ECM according to load, RPM's, and requested pressures to make the injectors work properly. It has the ability to be fully closed (delivering 100% of the pressure the pump is able to put out but very low volume) or it can be fully open (essentially dropping the pump output pressure to zero but with high volume in layman's terms) but the normal range of operation is - what - between 5% and 50%?

So when the injectors (or whatever failing component) have too much free flow and the regulator has to go beyond that normal range of operation the computer gets pissed off, sets a code, and goes into limp mode.

Kennedy's solution tweaks the "normal range of operation" to something that is technically out of the engineer's specs, but allows normal operation albeit with higher flows from the regulator to compensate for worn parts.


How'd I do?Essentially correct. The regulator will compensate for the failed component's (unaccounted) increased flow, causing the PCM to complain when the regulator requirement is greater than what is expected, according to the conditions. The PCM accounts for every drop of fuel through the system, and "knows" where the fuel should be going, as well as what is required of the components to accomplish that.

[dougmac]

The regulator will compensate for the failed component's (unaccounted) increased flow, causing the PCM to complain when the regulator requirement is greater than what is expected , according to the conditions. The PCM accounts for every drop of fuel through the system, and "knows" where the fuel should be going, as well as what is required of the components to accomplish that.

I don't believe this to be true and I don't understand the term "complain" as it relates to the pcm. I see no trouble codes that indicate a fault condition exists when "the regulator requirement is greater than expected" and it is not listed as a condition for setting the P0087 trouble code or even mentioned anywhere in the P0087 trouble shooting chart.

Excessive injector spillback is however mentioned as a cause.

What leads you to this conclusion?

[dougmac]

It is completely flawed logic that the pump does not pump to capacity when it sees a pressure below requested condition.

Equally flawed is the statement that it reduces output as a protection mode for the pump. There is less pressure on the internal parts because the the rail pressure is reduced under these conditions. There is more fuel flow through the pump allowing for better cooling and lubrication. This condition is a less stressful to the pump than operating at full pressure with more limited fuel flow.... I am not sure what they would be trying to protect it against?

[rapidoxidationman]

I don't believe this to be true and I don't understand the term "complain" as it relates to the pcm. I see no trouble codes that indicate a fault condition exists when "the regulator requirement is greater than expected" and it is not listed as a condition for setting the P0087 trouble code or even mentioned anywhere in the P0087 trouble shooting chart.

Excessive injector spillback is however mentioned as a cause.

What leads you to this conclusion?


I'm going to preface this by saying two things:
1) I have nowhere near the knowledge base that other members here have, possibly including you.
B) When I need to I'm pretty good at sussing things out.

BUT:
Wouldn't "excessive injector spillback" cause the regulator requirement to be greater than expected?
and
As far as the term "complain" goes, is the lodging of a trouble code not a complaint as a result of the PCM seeing something out of spec?

I'm not trying to start an internet pissing match, but there's a great deal of real world experience on this board that may not be found in a tech manual or a P0087 troubleshooting chart...

'scuse me while I go pop another batch, this time with butter...

[dougmac]

I'm going to preface this by saying two things:
1) I have nowhere near the knowledge base that other members here have, possibly including you.
B) When I need to I'm pretty good at sussing things out.

BUT:
Wouldn't "excessive injector spillback" cause the regulator requirement to be greater than expected?
and
As far as the term "complain" goes, is the lodging of a trouble code not a complaint as a result of the PCM seeing something out of spec?

Yes, I would consider a code a complaint... there is no trouble code for "the regulator requirement is greater than expected"...


I'm not trying to start an internet pissing match, but there's a great deal of real world experience on this board that may not be found in a tech manual or a P0087 troubleshooting chart...

'scuse me while I go pop another batch, this time with butter...

I am supposed to rely the "real world experiance" with their calims that make no sense at all over the GM technical documents? I'll stick with the GM information. I have been in this business long enough to tell the BS from the truth, thank you....

[Kennedy]

I don't believe this to be true and I don't understand the term "complain" as it relates to the pcm. I see no trouble codes that indicate a fault condition exists when "the regulator requirement is greater than expected" and it is not listed as a condition for setting the P0087 trouble code or even mentioned anywhere in the P0087 trouble shooting chart.

Excessive injector spillback is however mentioned as a cause.

What leads you to this conclusion?


There is a LOT of diagnostics going on behind the scenes and it is my belief that most of this is only provided on a need to know basis.





It is completely flawed logic that the pump does not pump to capacity when it sees a pressure below requested condition.

Equally flawed is the statement that it reduces output as a protection mode for the pump. There is less pressure on the internal parts because the the rail pressure is reduced under these conditions. There is more fuel flow through the pump allowing for better cooling and lubrication. This condition is a less stressful to the pump than operating at full pressure with more limited fuel flow.... I am not sure what they would be trying to protect it against?



The pump can move to near capacity, but not full capacity. Additionally, it is controlled by a complicated set of PIDs, expected flow rates, flow limits, etc. These are based on small errors and large errors both positive and negative. These are likely there to provide a smoothing effect to prevent the pressures from spiking and sagging. I will not claim that I can even begin to understand the entire interworkings of these tables, but wheat I will say is that I have had solid success in tuning to help the pump stay on target.








I am supposed to rely the "real world experiance" with their calims that make no sense at all over the GM technical documents? I'll stick with the GM information. I have been in this business long enough to tell the BS from the truth, thank you....

So basically you joined the forum to call BS on me...

[More Power]

I have been in this business long enough to tell the BS from the truth, thank you....

I/we appreciate your input. Please don't let a simple disagreement dissuade you from helping others here. Your input is valuable.

One thing to keep in mind is that, from an owner/enthusiast position, we may view problems and resolutions a little differently than a GM tech or even GM might. For GM, they are concerned about emissions regulations and adhering to documented service procedures. For a GM tech, I imagine that what the GM service schools taught was considered the best way forward to solve problems. Sometimes it is, sometimes it isn't, depending on a point of view and who's money is on the line.

For most owners and enthuiasts, saving money, improving performance or reducing downtime are more important.

A Duramax injector changout is so very expensive. I don't think GM or the dealerships fully appreciate that. If there's a potential in some idea, program modification or product that will reduce the cost of ownership, we'll discuss it, analyze it and recommend it if it helps solve problems. None of us here like snake oil. Those products or procedures that fit into that category don't last long around here.

Back before the arrival of the Duramax, and even sometime after, the standard GM recommended repair for a 6.5L diesel "stalling" problem was to install a new electronic fuel injection pump. Millions upon millions of hard-earned dollars were paid/wasted by 6.5 owners for a new pump when all they really needed was a new electronic driver module that would have cost just a fraction of what a pump change did. Once we understood the problem and how to inexpensively repair it, we documented the resolution. Both GM and Stanadyne (pump manufacturer) eventually came to (were dragged kicking and screaming to) the same conclusion, but it took years. That's just one example of how we (vehicle owners and enthusiasts) helped to solve a problem.

Welcome to the board. Information is our biggest asset. Please continue to contribute. Jim

[Wingeezer]

Hi Folks,

New to the group and joined to see what I could learn about P0087 !!

I will say immediately that my diesel experience is virtually nil, so I am afraid I am much more here to learn than anything else!

We have a 2006 GMC 2500HD Duramax bought new to tow our 31 ft Airstream travel trailer (about 8000 lbs loaded).

The truck has been great until earlier this month when returning from Cape May NJ to our home near Toronto.

Just after crossing from Pa. to NY, our truck suddenly went into (what I have now learned to call!) limp mode.

I got a "reduced engine power" message followed by a "service fuel filter message." All a bit scary when towing in the fast lane on the interstate!

Of course I knew nothing of the common P0087 problem but have read a lot since!

I had checked our fuel filter status earlier in the day and it showed 53%, now it showed zero.

I got over to the shoulder and tried shutting the engine down and re-starting but no change. We still could only maintain about 20mph max. (Now I think that with what I have learned, that maybe I should have waited 20 minutes or so and we might have gotten out of limp mode - but for how long?)

We limped for 5 miles to a Chev dealer at Dansville NY. We had fuelled up at a pretty seedy service station earlier in the day and I was sure our problem must be bad fuel with the apparent rapid demise of the fuel filter.

I explained what had happened and left the truck with teh Chev dealer, asking if they could check it out, change the filter that was apparently needed, and dump the remaining 1/4 tank of fuel if they deemed it wise and could do so.

When we returned, they had changed the filter, the engine light was off and the truck was back to normal, but they said that they felt the fuel was ok and they did not dump it.

I was told there were no codes, and they felt we would be ok to continue our trip home. They had no explanation as to what had happened.

At the time, I new absolutely nothing about OBD2, but now I am wondering how the engine light could be on with no codes present ? Maybe that is possible?

We did get home without further problem, but I am now concerned about recurrence. We normally head to Arizona in winter and hope to do so next Feb.

I certainly lack the insight most of you guys have, and so far, all I have done is to buy a spare Delco fuel filter that I will carry, learned how to change it on the road if I have to, and also bought an ET-80 code reader to at least be able to erase future codes and hopefully carry on, if only to a GM dealer!

Before we head south in Feb. I plan to explain what happened to our local GMC dealer and ask if there is anything further they can check out for us - I sure don't like having to worry about this sort of thing when towing on the interstates!

This morning, I tried out the code reader for the first time. Lo & behold, there was a P0087 code logged - but all indications are that the truck has been running fine since we left the GM dealer in NY. The fuel filter life is showing showing 98%.

I am at a loss as to why the code is there.

Did the dealer lie to me about checking for codes? Could he have turned off the dash engine trouble light without checking for codes and deleting them?

Maybe the code has been logged since being at the dealer - but if so, would we not also have have gotten the engine light back on again and maybe also gone into limp mode? Confusing!

After copying out all the freeze frame data, I erased the code and will see if it comes back - though it may not since we won't be towing the trailer again until Feb. It may be we need the heavier towing operation to cause a repeat

One way or another I still plan to see what our local GMC dealer might be able to do to hep us.

I still have extended warrantee on the truck until Nov 2014. I sure wish the problem was just a load of bad fuel, and maybe it was, but the dealer in NY didn't seem to think so, and after reading the thread on this forum, I now realize there could be a lot of other issues besides bad fuel.

The fact that the fuel filter life dropped from 53% to 0% in one morning makes me still suspicious about bad fuel, but i don't know how this monitor actually works.

I would have thought it monitors pressure drop, but I have read that it may just be mileage based. But if that is so, how could it drop from half life to zero in a couple of hours driving?


Differences I see though with our situation compared to what I have read that other folks have experienced with this problem include:

- temperatures were not high, maybe 70-75F

- we were not towing on a steep grade when this happened, although we had been in hilly country an hour or so earlier

- our truck only has about 62,000 km (38,750 miles)


Not sure what else I can do at this point. I have read about the kinked fuel line possibility and will discuss with our dealer. I have read about lift pumps, but I imagine GM does not support such a modification and it may well void my warrantee were I to get one installed so I would be reluctant.

Presume that with my code reader I can at least erase the code at the side of the road (believe engine must be stopped to erase) and that would at least temporarily remove the limp restriction.

I will also take a look at the fuel cooler and pressure wash it, although in our case, I doubt this would be an issue, the truck stays pretty clean!

I can also try to ensure we always refuel at half tank.

Not sure there is much else I can do, but any advice appreciated! I sure would like to regain confidence that this won't be a recurring issue in future! Up to now I have been very happy with the truck!

Apologies for the lengthy post !


Regards ........ Brian M.

[IGO1320]

I was getting the dreaded P0087 towing in the heat up steady/steep inclines. I first tried changing the fuel filter, then installed a Kennedy lift pump, both had no effect. Used a tech2 and commanded the injection pump full fuel pressure which it did and held. I talked to a Fuel injection shop and they told me I would need to replace my injector pump and "maybe" the injectors, they could not get to me for three weeks. I read another thread on another site and John Kennedy told someone with similar symptoms to mine that the problem was the injectors and that he could possibly tune around it. I called John and we discussed my problem he told me there was an 80% chance that he could write a tow tune that would make as much power and not set the dreaded P0087 thereby extending the life of my injectors (John says the injectors wear and start bypassing diesel) so I bit the bullet and ordered one of his tunes. I could not be more impressed, I have now made two trips to Hershey Pa., one to Billings Montana, Mesa Az., then Ohio to Florida by way of Kentucky and Tennessee where I have towed 8K-12.5K Fifth wheel TOY haulers/campers with no codes. John wrote the tune for my truck and had it out in an afternoon. I also stopped by to meet him at his shop, he made a couple minor changes to my tune no charge and took the time to answer a laundry list of questions, very impressive individual. I don't want anyone to think I am bad mouthing my old "box" tuner the Hypertech did serve me well for only $300 and without a way to clear the codes I would have really been in a pickle. I am using the Hypertech to clear codes if needed again.
As a side note with the old tune my EGT's had to be watched with a heavy load as up a steep incline in the heat they would go over 1400 forcing me to slow and downshift with this Kennedy tune the EGT's have not gone over 1320, I can just leave the cruise on and let her climb. I think the mileage is .3-.5 a gallon better but these trips I ran 65 instead (testing to see if I could "force the code") of my normal 61-62 so I will have to average that for a few more trips. The only downside is subjective and that is the truck "seems" to be slightly louder at idle, my wife commented on it without my input so that may be true, but that makes no difference to me the tune is as billed and appears to have extended my injector life without a loss of power and possibly an increase in mileage. I would highly recommend John if you are interested in extending the injector life by holding the dreaded P0087 at bay.
I have 287,000 on my truck now, I had 260'ish when the problem started and I "drove around it" for 10K miles, so I now have roughly 17,000 on the tune.

[AHGSP]

Like Brian, "Wingeezer", I experienced a similar and rather disconcerting situation last eve; while hauling a 12k# horse trailer up a steep grade in Western MD, going Westbound up the Eastern Continental Divide on I68.
This was particularly disconcerting in, if I break down with horses and dogs on the side of the interstate, this could become quite problematic in getting the horses and dogs I have onboard safely back home, or somewhere safe.

Background info:
I had filled up prior to my trip and had checked the fuel filter life on the DIC and it was showing at around 28% life left. With a planned training trip(I Professionally Train and Field Trial Bird Dogs) to SD next Friday, I figured I would change it out next week prior to my trip anyway. Temperature was not particularly high, 70* + or - and when the code set and truck went into limp, I had approx. 24-28 gallons of fuel in the tank, engine temp. had climbed to around 210-220 and tranny temp was running right around 200-210. Right before it went into limp and set the code P0087, the "Change Fuel Filter" came up on the DIC and sure enough, it now showed 0% life left, same as Brian. The truck is a '08 3500 DRW Crew w/ flatbed, has just shy 112k miles on it and has been religiously maintained, with approx. 20-30k of those miles towing this rig. In addition, the truck is entirely stock beyond the flatbed.

I changed the fuel filter along the roadside and while the check engine light did not clear, I experienced no further limp and was able to turn around and safely return home with the horses and dogs. Should the light have cleared?

My questions are:
Was the fuel filter condition/poor fuel the most likely culprit in this case, combined with the steep grade and temps?
What scan tool is recommended so that at the very least, I may be able to clear the code/limp and continue on safely, should I be a thousand miles from home when this happens, IF it should happen again? I could care less about myself, I'm a big boy, but these horses and dogs depend on me to take care of them and assure their safety.

I plan to follow through with some of the many suggestions here, on this MOST HELPFUL thread and clean the cooler, check fuel lines, most likely add the dual lift pumps as soon as I can afford the extra expense of the mod. I have also read Kennedy's Tech Tips for other idea's and suggestions; but what else might you folks suggest?

Thanx Kindly in Advance for any and all suggestions, as well as this extremely helpful resource!
Bruce Shaffer

[IGO1320]

I would follow John Kennedy's recommendations. I bought a pressure/vacuum gauge from him, if the code occurs again you can plug it in and see what the vacuum is then you know if the filter is plugged. Off course you need to know what normal for your truck is first, there is some variance. You can buy any cheap scanner to read and clear the ECM codes, to read the other cpu's (ABCM, SRS,TCM, ect.) you will need something much more expensive.

[More Power]

Glad to see some new faces here in the board! More info is better.


Used a tech2 and commanded the injection pump full fuel pressure which it did and held.

Perhaps the best time to test for commanded/actual pressures is when you're having a problem. Once the truck has cooled and the fuel has cooled, pressures could be normal.


Wingeezer: Differences I see though with our situation compared to what I have read that other folks have experienced with this problem include:

- temperatures were not high, maybe 70-75F

- we were not towing on a steep grade when this happened, although we had been in hilly country an hour or so earlier

- our truck only has about 62,000 km (38,750 miles)

There will always be an exception to the rule, an example that doesn't fit the norm for a P0087. In your case, I'm surprised you don't see this P0087 problem become much-much worse when it's hot outside and you're working the truck harder - assuming that a fuel filter service didn't solve it.

Thanks for posting. Jim

[Kennedy]

winegeezer,

My guess is that the dealer did not bother to hook up and check for codes. The fuel filter life dropped due to the P0087. We see this quite frequently where filter life gets zero'd out due to pressure maintenance issues.

You've made great strides in equipping yourself as I have been recommending for years.

You should always have a minimum of one fuel filter as well as the tools required to change it. I've also been working on a mini compressor and tire plug kit for my vehicles as well.

To save you getting dirty next time the P0087 code comes up and potentially prevent replacing a fuel filter unnecessarily, I also recommend the kit shown below. This way you know instantly whether the filter is truly restricted, or not.


http://www.kennedydiesel.com/images/Dmax-fuel-filter-rest1.gif

[Jeff Paxton]

Update: We completed the trip from eastern CO to New Jersey about a week ago. The temps were mild, less than 75 degrees. The truck performed very strong through the mountains of PA which is where the problem erupted last spring, but at higher temps, 90-93. It shifted into 4th far fewer times than previously, and when it did, the climbs at 65mph were comparatively effortless. In the spring, each time it shifted into 4th, there was not much throw left on the throttle, and within a few seconds, limp mode and power loss. There was plenty left this trip. It seems the replacement fprv is doing what I need. I will not be 100% confident until it is tested in high temps next spring, but I am pleased at this point.
I believe the old fprv weakened quickly with each limp, and had reached the point where it was never "closing" all the way. I think it explains everything, especially since the balance rates on the injectors checked out fine each time observed by "trusted" sources. High temps will be the last test.

[Kennedy]

I believe the old fprv weakened quickly with each limp, and had reached the point where it was never "closing" all the way. I think it explains everything, especially since the balance rates on the injectors checked out fine each time observed by "trusted" sources. High temps will be the last test.

I did not see if a "bottle test" was performed to verify the leakage?

IF the relief valve was bad it definitely weakened each time it was activated. The valve gets extremely hot when activated and this weakens the spring. We typically get away with shimming the spring and all is well again. The thing is, it typically does not activate unless there is severe pressure cycling. This pressure cycling is caused by supply side restriction ie: plugged fuel filter, or excess air in the system. My recommendation has always been that these trucks need a lift pump to ensure proper filling of the OE fuel filter and to prevent outgassing of the fuel creating large amounts of "air" in the fuel filter housing.

[IGO1320]

Well hot weather is gone and chain season is upon us if we want to tow out west, so I am done till spring (out west anyway). Still no P0087 made several more trips to Kalifornia, Utah, and Arizona.

[Fiber Cowboy]

I will start with saying this is the best forum I have found in two years dealing with the same problems everyone else is.. Let me start with letting everyone know I purchased my 06, 4x4 crew 3500 new. I hauled 4000 to 10000 lbs coast to coast on random trips up to 75k miles. My normal travel was under 25 miles a day. In 2011 I started a new business in underground and started hauling 14K trailers 2 to 4 hour trips weekly, leaving my truck idle for 10 hours a day ect. Things were great until the August of 2012 while driving in 100+ temps on fresh blacktop... Engine code came on truck went into limp... After spending 2 months and 2000 dollars at 5 dealers getting 4 fuel filters on my 105K millage (out of warranty) truck I was pissed 4-5k to fix, no forums supported this as a solution that worked. I complained about the 250 degree fuel temps and was told by GM that it would have no bearing and was normal. I then discovered the fuel heater was stuck on and boiling my fuel for two months. Changed the entire fuel primer assembly and drove 65K last year no problem leaving the heater unplugged. (as mentioned here). The entire time the code comes on but only failed again this year. I have had my truck drop into limp mode as many as 15 times in 400 Midwest miles using only a 5 min restart on the highway.. Code does not clear but truck wants to run at 80 with a load... No rime, no reason...
My problems:
Heat outside 75 to 100+ Yes
Load causing failure Yes
Large hills with headwind Yes
Quick slow downs under load YES
tired of dealing with YES

I'm not clearing codes but once every few months but never have a performance issue until above conditions exist. I'm 100% stock, the Black Pearl works hard and gets stretched maintenance.. This is the best vehicle I have ever owned but I need a real solution to a heat/load related issue that does not require a engine rebuild.

220K with 7200 hrs and still breaks the tires loaded with 4 men, tools and trailer...

BTW: 50+ professional drivers with no CC and tuners. No problem from 100 to 400K on trucks....

[a5150nut]

My problems:
Heat outside 75 to 100+ Yes
Load causing failure Yes
Large hills with headwind Yes
Quick slow downs under load YES
tired of dealing with YES

I'm not clearing codes but once every few months but never have a performance issue until above conditions exist. I'm 100% stock, the Black Pearl works hard and gets stretched maintenance.. This is the best vehicle I have ever owned but I need a real solution to a heat/load related issue that does not require a engine rebuild.

220K with 7200 hrs and still breaks the tires loaded with 4 men, tools and trailer...

BTW: 50+ professional drivers with no CC and tuners. No problem from 100 to 400K on trucks....


Cowboy,

I don't have a DMax just a 6.5. But one thing comes to mind reading your problems. Are you having any heating issues? And have you ever broke apart your cooling stack and cleaned out between the cores?

[Fiber Cowboy]

I have not done anything to the cooling system other than have it flushed at 100K and at 200k. Just recently a friend recommended changing the thermostats because that worked for them.. I did do this and got about 20HP back but the truck runs at 200 to 210 with or without a load and has all along. It still breaks down though. I've be considering trying the fuel line. I also wonder if the Catilitic Converter is clogged. After idling for long periods my exhaust is blue and stinks like something rotten.

[Fiber Cowboy]

I forgot to mention that the 100K flush included a new radiator due to an accident. They replaced the radiator, Tran cooler and AC with GM parts.

[IGO1320]

I will start with saying this is the best forum I have found in two years dealing with the same problems everyone else is.. Let me start with letting everyone know I purchased my 06, 4x4 crew 3500 new. I hauled 4000 to 10000 lbs coast to coast on random trips up to 75k miles. My normal travel was under 25 miles a day. In 2011 I started a new business in underground and started hauling 14K trailers 2 to 4 hour trips weekly, leaving my truck idle for 10 hours a day ect. Things were great until the August of 2012 while driving in 100+ temps on fresh blacktop... Engine code came on truck went into limp... After spending 2 months and 2000 dollars at 5 dealers getting 4 fuel filters on my 105K millage (out of warranty) truck I was pissed 4-5k to fix, no forums supported this as a solution that worked. I complained about the 250 degree fuel temps and was told by GM that it would have no bearing and was normal. I then discovered the fuel heater was stuck on and boiling my fuel for two months. Changed the entire fuel primer assembly and drove 65K last year no problem leaving the heater unplugged. (as mentioned here). The entire time the code comes on but only failed again this year. I have had my truck drop into limp mode as many as 15 times in 400 Midwest miles using only a 5 min restart on the highway.. Code does not clear but truck wants to run at 80 with a load... No rime, no reason...
My problems:
Heat outside 75 to 100+ Yes
Load causing failure Yes
Large hills with headwind Yes
Quick slow downs under load YES
tired of dealing with YES

I'm not clearing codes but once every few months but never have a performance issue until above conditions exist. I'm 100% stock, the Black Pearl works hard and gets stretched maintenance.. This is the best vehicle I have ever owned but I need a real solution to a heat/load related issue that does not require a engine rebuild.

220K with 7200 hrs and still breaks the tires loaded with 4 men, tools and trailer...

BTW: 50+ professional drivers with no CC and tuners. No problem from 100 to 400K on trucks....

Talk to Kennedy. You first need to make sure that actual keeps up with commanded fuel pressure. Your symptoms seem to mirror what mine were, if that is the case my injectors are worn and Kennedy sold me a program that has temporarily fixed the problem. I have about 60K on it since the fix, and I also get slightly better mileage towing which is a plus. Call Kennedy diesel and do as he recommends, John is a very straight up individual.

[TreeFarmMech]

First of all, let me say thank you to the forum and its members for providing such great information that anyone with Google can find. My hat is off to you!

I've been battling a p0087 in an 06 GMC 3500 used to haul containerized trees around South-Central Texas. Tall and heavy loads, heat, head winds, and hills are all a part of 95% of the miles on this truck.

When the p0087 first showed up at 120k miles (18+ months ago), I immediately Googled it and after reading through numerous forums, I decided that ultimately the injectors are to blame, I skipped the rigamarole of debate and went ahead and had it done. A big chunk of change sure, but delivering is the most important aspect of our business and without our sole delivery truck, we weren't making any profits.

Fast-Forward to mile 155,237. A hot day in early June, heading from Columbus to Austin, a load no heavier and taller than any before. 30 minutes after leaving the farm and bam, code. Going up a hill, truck downshifted to 4th, (no cruise, tow/haul on) and hiccuped. A long miserable day of sitting on the side of the road, waiting for the code to auto clear. Anyway, by the time I got home, the code had thrown a grand total of 8 times (5 loaded, 3 empty). I hadn't seen this code in over 25k miles, and now 8 times in one day? What gives?

I read through this forum last week and have compiled a laundry list of things to do first. And was ready to get to work when...

My Schaeffer's rep called. This gentlemen truly has been there, wrenched on it, and lived to tell about it. So I ask him what is your take on a low fuel rail pressure code in a common rail diesel? With out a hesitation, "Your return lines are clogged."

Say what?!?!?!

"Well its simple sonny, your not flowing what is needed to keep the diesel fuel and associated parts cool. Your diesel is getting hot and your pump can't pump it. Its too thin."

My eyebrows are raised as I've read multiple people complaining about high diesel fuel temps. "Go on..."

"American diesel is junk these days. It grows algae and no one ever cleans their stock tanks. Everyone of those companies are selling junk diesel. He**, they're buying it as junk right off the tanker at the Gulf! There is algae growing in every stock tank in America, I don't care how cold it is."

So what is my fix?

"Shock your tank, Schaeffer's Fuel Shock #285. It'll kill that algae living in the plastic tank and in the aluminum lines. It'll clog your filter to hell but it'll work."

OK, how much?

$72 per gallon. One Gallon treats 4,000 Gallons of fuel.

Really? Give me a bottle.

Got me a turkey baster and shot 1 ounce of this stuff into each 20 gallon tank yesterday afternoon. Made a delivery this morning, no code, but the 3500 didn't quite have the gusto I was expecting. Maybe we need some more miles I thought. Got home, unhooked the truck and was authorized to joy ride the remaining 25 gallons of diesel in the tank away.

On the very first punch to get on to the highway, she heaved bad, AND THEN ROCKETED AWAY! This truck hasn't accelerated like that in a loooong time. That wasn't a down shift heave either, she was already winding up in a lower gear. This hesitation came right in the middle of two gears. When I lurched forward in my seat, I thought for sure I was going to get chewed out for destroying the truck...

Called my Schaeffer's rep. He explained to me that algae actually grows into the pores in the plastic and aluminum. You can't pressure wash that stuff out. Petroleum cleaners aren't terribly effective. I can't pronounce what is in this bottle but it definitely is some sort of organism killing stuff.

I'm off to finish burning those remaining 20 gallons and change my fuel filter. Next tank is getting Schaeffers #137. I'll post back after the next delivery. Until then...

[rapidoxidationman]

Begs the question: How many truck owners who have experienced the P0087 code use (or more specifically DON'T use) fuel additive/lubricant/conditioner/algaecide?

I use Power Service gray bottle religiously and (knock on wood) haven't had a problem. 190K miles on my '05.

[Kennedy]

A quality additive run consistently will prevent occurrence of microorganisms and keep the system clean and healthy. I'm an anti Power Service guy. FPPF Total power or in a pinch Stanadyne performance formula.

I seriously doubt that a chemical treatment of the fuel was necessary nor that it made any long term improvement, but I could be wrong.

[HobbleCreek]

What are you guys using to clear this code when you get it?

[TreeFarmMech]

What are you guys using to clear this code when you get it?

Any OBD-II scanner with code clearing capabilities (some are only designed to read the code and NOT clear it). I'm not sure how anyone else is performing the action, but I pull off the road, trun off the truck, connect the scanner, turn the key in the on position with the engine off and proceed to operate the scanner. Any parts store can sell you one. You can find them on internet, pretty much anywhere.

I picked up an Innova Model 3120b. It doesn't have the graphing function but I can read the freeze frame with and note some (not all) sensor outputs.

How much you spend is completely up to you.

[TreeFarmMech]

An update from my previous post for anyone still working on this.

Did not have an opportunity to run the truck last week, no deliveries came up.

Used all the "old" diesel, installed a new fuel filter, drove around town a bit last week. Delivered a moderate load today, certainly not qualifying as "heavy". Headed to Austin on Hwy 71. 18 miles from the farm (about 60 on the fuel filter) and code thrown. A/C on, Cruise off, tow haul off, just driving normally, trying to keep above 70 mph, 81 degrees out, wind left to right 15-20 mph, moderate incline (nothing near 6%).

Modified my driving habits mid trip. I would accelerate down hill and refrain from depressing the accelerator pedal when headed up hill. Even pulled my foot out of the pedal on some of the steeper inclines.

Got to a section of 71 where there are some traffic signals. Used this opportunity for some full throttle acceleration. Couldn't get a code no matter how hard I mashed the GO! pedal. This is interesting to me. I'm getting up in the rpm range, I'm figuring my injectors are staying open a little longer, turbo is winding up, boost PSI is pretty up there, this motor is giving it everything it has, demanding higher fuel rail PSI. Why no code, especially with the injectors staying open longer dumping more fuel? Sure the CP3 is spinning faster, probably has a pretty good vacuum on the suction line (any hose pinching problems should be pretty obvious).

It got me thinking about it, this code is throwing under 2,000 rpm in high speed and loaded conditions in high gear.

Got to the delivery site without much opportunity for further testing. Oh well. Continued to ponder on the drive home from Austin and took the opportunity to test a little more.

I've narrowed it down to these conditions:
(1) Transmission in drive
(2) Any speed with the transmission in 6th gear (for me 52 mph or higher)
(3) A slight depressing of the go pedal while going up hill (even some not very steep) (pushing it to the floor makes the transmission down shift)
(4) A trailer connected (even an empty one)

With these conditions, this code throws every time.

So I popped it into manual (M on the dash) and selected 6 as my range to see what happens. Couldn't get the code to throw to save my life. I even turned around and went back to the last hill the code popped on. Still couldn't get it to do it.

So for now, I'm driving in Manual.

Further thoughts: Why does this code pop only at highway speeds with slight desired acceleration? Something to do with the transmission and engine communication? Anybody know how many sensors are in an Allison transmission? Why does the transmission, under full throttle acceleration, shift from 4th to 5th at 2700? Why is there a 6-700 rpm drop going to 5th? My foot is still in the pedal, I wanna stay up in the power band, not drop below it. Why, when the code throws, am at 92% (or more) calculated load? Where is this load measured or how is it figured? Why does my truck think it is so loaded with an empty trailer weight of 3,000? Is my transmission causing the increase in resistance? We've religiously maintained the axle bearings on the truck and trailer, they spin very easy by hand.

I'm beginning to think my problem isn't in the fuel system, its in the transmission. Something is telling my fuel system to go to max PSI with a slight depression of the accelerator pedal, WITHOUT down shifting the transmission, allowing more RPMs, boost PSI, etc.

Anyone know anything about an Allison 1000 transmission? I found this video:
http://www.youtube.com/watch?v=8xFwoTCInY8

(According to this video, Allison 1000 gear ratios are 3.10, 1.81, 1.41, 1, .71, .61, hence the big drop from 4th to 5th and the only slight drop from 5th to 6th.)

Do I have a failing torque converter? A faulty pressure sensor in the transmission somewhere? A leaking valve body? Is there anywhere I can plug my scanner into this thing to find out? (No there isn't, unless your trans is post 2009, when "prognostics" was added).

I remember older transmissions had a "dump" valve that was mechanically operated by the opening of the throttle. In higher gears, this valve would cause enough loss of fluid psi to down shift the transmission allowing the torque converter to spin faster and thus re-raise fluid psi while accelerating the vehicle. How is that accomplished these days with all this wiring harness connected to this transmission?

[Kennedy]

The chemical treatment has not cured your P0087 code correct?

Modified driving habits have helped you skirt around it correct?

I will stick with my original comments that this is fuel supply related:

A lift pump keeps the system under pressure happier and healthier

Secondary filtration keeps the fuel system happier and healthier

Regular use of a quality fuel treatment will often pay for itself with a small bump in economy and keeps the fuel system healthier and happier


Now as to the issue, heavy load high gear low RPM high ambient temps and very high fuel temps are the factors. The return flow is greater than expected due to injector wear. When operated in these conditions, the pump flow is insufficient to maintain demand. I have had some success with manipulation of the pump though ECM programming as IGO1320 has reported. Not 100% surefire, but pretty darn good.

[TreeFarmMech]

The chemical treatment has not cured your P0087 code correct? It does not appear so. Oh well. :p

Modified driving habits have helped you skirt around it correct? Yes, but why does operating the truck in manual mode (with 6th gear selected) and driving normally not cause a code? Is the ECM in a different set of parameters for operation or something?

I will stick with my original comments that this is fuel supply related:

A lift pump keeps the system under pressure happier and healthier

Secondary filtration keeps the fuel system happier and healthier

Regular use of a quality fuel treatment will often pay for itself with a small bump in economy and keeps the fuel system healthier and happier


Now as to the issue, heavy load high gear low RPM high ambient temps and very high fuel temps are the factors. The return flow is greater than expected due to injector wear. When operated in these conditions, the pump flow is insufficient to maintain demand. I have had some success with manipulation of the pump though ECM programming as IGO1320 has reported. Not 100% surefire, but pretty darn good.

I'm speaking for myself, but I had Lite Load, high gear, low RPM, moderate ambient temps (it was only 82 degrees yesterday). If a brand new set of injectors is wearing out after 25k miles, either the filter isn't doing its job or the CP3 has gotten weak (or the dealership installed crappy injectors, known to happen...:mad:). But others have posted here that replacing the CP3 didn't work either.

I'm not convinced a fuel supply problem, this code should be popping up under hard acceleration (mashed pedal) & loaded conditions if fuel supply was the issue.

Correct me if I'm reading the wrong information but the CP3 is mechanically powered off the cam chain. The only way the ECM can modify fuel pressures is with valve bodies in the CP3 and the FPRV.

What if I have a leaking intake system (think air entering the system AFTER the MAF)? Under high RPMs (more than 2k) vacuum could suck the leak closed, under low RPMs not enough vacuum to pull it closed. Is there an 02 sensor in the exhaust or something reporting exhaust conditions to the ECM? If so, it could be reporting excess 02 (compared to the MAF) and the ECM is trying to compensate by commanding more PSI than the pump is physically able to provide at under 2000 engine RPMs.

I'm still miffed that the transmission doesn't down shift out of 6 with any light/moderate depression of the accelerator pedal, this just doesn't seem normal to me (especially in "Tow/Haul" Mode). If this is truly the case, the transmission can take a lot more torque than the motor can provide (ie, at 65 mph and ~1600 rpm, the transmission is telling the motor "you aren't overloading me, no need to down shift" and the motor is struggling to put out the power to keep the vehicle/trailer going up a moderate incline).

http://www.dieselpowermag.com/features/0603dp_2006_gmc_sierra_3500_review/

According to this article, the LBZ outputs 650 ft-lbs at 1,600 rpm. Times .61 (6th gear ratio) = 396.5 ft-lbs of torque at the back of the trans, times 3.73 rear end ratio = 1,478.95 torque @ 8.25" ring gear divided by 3.6 (tire diameter 29.75" divided by ring gear diameter) = 410.82 calculated torque at wheel/pavement contact of a brand new from the factory vehicle. Is that enough for approximately 10,600lb vehicle combo (~6600 vehicle (I have crew cab, "8 ft farm bed" + tool box and 2 20gal tanks) and 4,000 lb empty trailer) at highway speed up a moderate incline? Never mind the the power lost to heat, windage, alternator, a/c system, 150,000+ miles of wear on the engine, etc.

All that said, perhaps I have a clogged up catalytic converter? After 150,000 miles of dirty diesel (approximately calculated 18,750 gallons) causing excess hydrocarbons in my exhaust... Clogged cats can cause higher engine compartment temps. Anybody else noticed that the fuel supply lines are rather close to the drivers side exhaust manifold and the water separator/fuel filter sits right next to the passenger side exhaust manifold? And since the LBZ has EGR cooling, those hotter exhaust temps are flowing through the air cooler, raising temperatures entering the engine compartment. Now we have heat added all over the place due to a clogged CAT. Is this train of thought out of whack?

Has anyone with the catalytic converter delete experiencing the p0087?

[TreeFarmMech]

So crawling around under the truck, I failed to find any sensors after the EGR components. So much for any 02 sensor readings going to the ECM ;)

I also found that the EGR cooler utilizes the engine coolant to cool the exhaust gases, not the air cooler mounted on the front of the vehicle. :o

So now the cheapest option before me is a deleted catalytic converter. The idea being to prevent the EGR system from cycling higher than normal exhaust temp back into the engine compartment by getting that exhaust out the back of the truck.

I can't help but think that the close proximity of exhaust and fuel components is a contributing factor to this.

Most people posting with this issue use the vehicle for a significant amount of towing. They also seem to not have bunches of mods to their vehicles. Begs the questions:
Why aren't the modded exhaust system guys suffering a p0087 code?
Why aren't the people not towing anything suffering a p0087 code?
We've figured out the fuel treatment folks aren't having a p0087, go figure, they have cleaner burning fuel dumping less hydrocarbons into their catalytic converter and EGR system is taking the brunt of a clogged up exhaust pipe, its the only other direction for all that hot air to go.

If only GMC would have told me to upgrade the exhaust, use fuel treatment, and block off the EGR when we bought the truck. :p

[mramsey63]

Thanks to all that have added their knowledge on this subject.

I have a 2007 GMC 3500 with 455,000 miles, completely stock and use the truck to deliver campers to all 48 lower states. I have been getting the dreaded 0087 code for the past year. I do have a Bully Dog connected but is not installed, only used to monitor temps and to clear codes.

I have a few questions I'd like to ask.

1 Has anyone found a true solution to this issue?

2 Kennedy I've noticed that it seems you believe it will be the injectors almost 100% of the time, but I have noticed 2 or 3 people have had their injectors replaced and it didn't solve the problem for them. What do you feel is happening to these trucks since they do have new injectors installed?

Thank in advance.

[Kennedy]

I can only go by what has worked for me in the cases that I have been directly involved with. Some that have done injectors and still had issues could have been overlooking fundamentals ie supply side restriction/lack of lift pump, or gotten poor quality injectors, or had a weak tired CP3. Hard to say.


It those cases we have successfully handled some with injectors and some with lift pump supply usually accompanied by tuning as well.

[Kennedy]

Just an update:

I have been dealing with 2 different LLY (technically LBZ) medium duty trucks battling P0087.

Truck #1 had a lift pump previously and we went through 2 unsuccessful rounds of tuning to fix his issues. Round 3 of tuning was sent last week.

Truck #2 had no lift pump but added my twin lift pump setup. This reduced his frequency of P0087's by 50% so we moved on to tuning. I based this tuning off what I had done for truck #1 even though I had not yet heard back.


Both owners called me today to report that the problem was solved in this weekend's operation. They both tried to throw what they could at their trucks and they just kept rolling. Truck #2 had a lot of black smoke prior to the tuning also which reportedly cleared up. Will keep in touch with them to monitor progress.

[rowekmr]

I have been doing my share of internet researching and besides fuel filter change and lift pump most other people make changes without a lot of evidentiary support. It seems people throw CP3's and injectors without really knowing if they are bad. I did some research on a professional mechanic database that accesses GM's info and it seems that they have a return rate test for the injectors that can at least assure an owner if the injectors are bad before spending 4K replacing them. The test for the CP3 were less precise more of a process of elimination but again I would try that before spending the 2K unless I just wanted to upgrade my components. They also had a test for the FPR on the CP3 but don't know how often they fail and the had a bottle test for the pressure relief valve on the fuel rail (forgot the name).

Since I now have a LBZ with the P0087 code I will do some more research and try to be systematic in replacing and hopefully from the cheaper side up instead of the other way around. One thing I can understand is the collapse hoses, fuel under vacuum (creating air bubbles) can both be cured by lift pump much less CP3 longevity which I believe the other manufacturers use in their diesels. I am surprised GM eliminated that component in their design esp since the previous design (6.5L) had lift pumps too.

[Kennedy]

I have been doing my share of internet researching and besides fuel filter change and lift pump most other people make changes without a lot of evidentiary support. It seems people throw CP3's and injectors without really knowing if they are bad. I did some research on a professional mechanic database that accesses GM's info and it seems that they have a return rate test for the injectors that can at least assure an owner if the injectors are bad before spending 4K replacing them. The test for the CP3 were less precise more of a process of elimination but again I would try that before spending the 2K unless I just wanted to upgrade my components. They also had a test for the FPR on the CP3 but don't know how often they fail and the had a bottle test for the pressure relief valve on the fuel rail (forgot the name).

Since I now have a LBZ with the P0087 code I will do some more research and try to be systematic in replacing and hopefully from the cheaper side up instead of the other way around. One thing I can understand is the collapse hoses, fuel under vacuum (creating air bubbles) can both be cured by lift pump much less CP3 longevity which I believe the other manufacturers use in their diesels. I am surprised GM eliminated that component in their design esp since the previous design (6.5L) had lift pumps too.

I wish you luck in finding your issue and will watch for the resolution.

The issue is that the P0087 does not happen at idle, cranking, or low pressures where these tests are performed. It happens at high ambient and fuel temps and under heavy loads which is where the highest pressures are called for.


The 2001 LB7 tends to have chronic fuel pressure codes as well. I've done many hundreds of tunes for these. The DTC is P0093 large fuel leak detected. It seems that once the bug bites these trucks all the parts changing you can do will not cure it. I've been seeing the P0087 fixed with pump and injectors only to come back in much less time. Could be sub standard reman injectors or it could be skeletons remain in the closet. Either way I am hopeful to have a tuning related cure. It is highly likely that I will soon be doing an ECM for a customer who replaced pump and injectors 100k ago and now has the issue returning.

[rowekmr]

From my limited driving of mines (200 miles) the code comes on after normal slightly aggressive driving empty (on flat lands) without high temps. Once the code is confirmed (CEL comes on) it has reduced power until I clear the code. When I did search there were those towing heavy in high temps and then there were people like me who are not operating at the upper limit of the drivetrain.

[Kennedy]

From my limited driving of mines (200 miles) the code comes on after normal slightly aggressive driving empty (on flat lands) without high temps. Once the code is confirmed (CEL comes on) it has reduced power until I clear the code. When I did search there were those towing heavy in high temps and then there were people like me who are not operating at the upper limit of the drivetrain.


Some of these can be as simple as a supply side leak or restriction. The black plastic fuel filters are often linked to this.

I have a ton of Tech Tips on my site regarding the P0087, bottle test etc.

[rowekmr]

Thanks I read those helpful tech tips posted on your website.

I have a few new is questions regarding the code.

Which sensor triggers the code or is it triggered by the computer from calculations? If it's a sensor where is it located?

What pressure threshold triggers the code? Is that threshold too conservative or can damage occur at that level?

[Kennedy]

The P0087 is sort of a convoluted mess. I can't really say precisely what sets it off. Partly because I don't know for certain, and partly because it's part of what I'm doing in the tuning.

What I can say is that this is the course of action:

1) Eliminate supply side restriction (lift pump preferably my twin pumps)

2) Keep the fuel cool-clean the cooler out (I've seen guys adding fans to help)

3) Bottle test (need to make sure nothing is escaping the relief valve (if the valve leaks its due to #1 above so fix that too)

Once you are there it's now a matter of change parts or programming or both.

In the past few years of working on this I've had what I'd call "decent" success with programming if the truck is marginal. Some that were really bad have had issues and needed injectors. The recent pair that I did were what I might consider really bad. The normal tuning that I did actually made it worse on one initially. This is mostly due to the fact that I also improve performance which does take more fuel. I'm pretty confident that I have things in good control now.

One thing I am starting to see is cases where a guy replaces injectors and often the CP3. The problem is fixed, but comes back even sooner than the previous time. Much of this is lack of TLC and adding protective measures like lift pump, added filtration, and quality additive, but I think some of it may also be systematic. With the 2001 P0093 being the equivalent error it seems with those trucks once you have the DTC the only way to fix it is through programming. This may prove true for the LBZ and LMM but only time will tell.

[rowekmr]

Coming from owning 2 of the worst reputation diesel engines (2x 6.0L and 6.4L) I am shock to hear how this engine has this one issues (P0087) with so many convoluted solutions. I heard so much that the LBZ is the gold standard duramax but honestly didn't know they had fueling issues until I got one.

Now back to mines I will do exactly what you recommend. You were the only definitive source of info that also provided the science behind it. Other places seem to do exactly what you mention throw a CP3 and/or injectors then wait and see but my pocketbook is too small for that kind of game of chance. Thanks for taking the time to share your vast experience you'll be hearing from me soon for that twin lift pump once I get the body work done!

[Jeff Paxton]

After thinking I had solved my particular variety of limp mode problem with the pressure relief valve "plug", I was wrong. Traveling in this springs higher temps, it was back with a vengeance. On the relatively short trip from Woodstown, NJ to Harrisburg,PA in May, the old truck fell into limp approx a dozen times. Oddly, not full blown 30mph limp, but around 50mph semi-limp. So I guess the plug was doing something, but I knew this truck was not making it back to Colorado.

I've sunk enough $$ into this truck for this and other issues. And after all it had 280k miles so I decided it was time. I traded it in. It will still make some farmer or kid a great daily driver, its just that its days of towing 14k were over. Here's hoping I don't re-visit the issue with the new truck!

[Kennedy]

I've been doing quite a few ECM tunes this season and while I can't work miracles I have made the truck much more useable. I have it to the point where if it does code the check engine light will come and let you know, but will continue to operate normally.

[blackcurse]

Hello, I just finished reading the 21 pages of this thread looking for a fix to this problem. I will give some background on my personal problem I am having with my 06 LBZ with 92,000 miles on it. When the following incident occurred, I already had the 4" down pipe back exhaust w/ no muffler, EGR block off plate, PPE race plug and PPE tuner on level 3, fuel rail pressure, boost and pyrometer gauges. This set up had been in the truck for years with no issues.

Last year 6/6/2015, i was traveling thru Mass. and stopped at a full service fuel station where, the kid pumping, filled my truck with gasoline. It was idling, I have 4" straight exhaust, a green gas cap that says diesel fuel only and I pulled up to the diesel pump. Needless to say, I only made it 3 miles up 495 before my truck died. I had no idea that it was full of gas. I cranked it over to try and start it, it tried to fire and the locked up. Hydro-locked, cylinders full of gas.
It got towed to GM certified Diesel repair shop #1, where they let it sit a week, fuel system full of gasoline, before they worked on it. They drained the fuel system, put some new diesel and an additive in it, changed the filter and said it was fixed. I drove out to Mass. (4 hours from my home) to get it, left the dealership, made it 150 miles down I-495 before my truck died. The only way I could get it to run was by pumping the manual primer, as soon as I quit priming it, it would quit.
Got towed to GM Certified Diesel repair center #2. There they replaced the CP3 and injectors. Called me a week later and said it was done. So again, I drive out to Mass. to get it. This time I make it home, and over the next few months it seems OK. So now its October and we decide to go camping, hook on my 30' camper and head up in the Adirondack Mountains. About an hour into the trip, yep, you guessed it, CEL comes on and the truck is in limp mode. First time this happened, did it 6 times on my 300 mile trip.
Over the winter, I battled with this issue by playing with the tunes, changed all rubber lines, replaced the filter housing, drained and cleaned the tank myself, cleaned the pickup in the tank, put in a PPE fuel rail fitting, took everything off and put the truck back to 100% stock, went back to my mods and nothing fixed the P0087 that pops up when I work my truck. It can be towing a trailer up a hill, hauling gravel in the bed, or just doing 4th gear brakestands, whenever i am hard on the throttle for extended periods of time, it will go in to limp mode and kick a P0087.
This spring I had to tow my camper to a motocross race, and drove 350 miles to and from the track in limp mode, and I continued to fight with the truck, but now it seems it will limp more easily. Used to be I had to really get on it to cause it to limp, but now I can be just driving the truck empty and if I go WOT long enough to pass a car or something, Voila, CEL comes on and P0087 is thrown. It now seems to be getting worse.
So I take it to GM Certified Diesel repair shop #3. They hook the gauges on to check low pressure supply rates and determine its a dirty fuel and air filter. Call me, say it's fixed. I go and get it and on my way home, I beat on it, and at about 125 mph, CEL come on and its in limp mode. Every time it goes it limp mode, at WOT my fuel rail pressure gauge goes from 26k at the initial throttle hit and fades down to 4-5k. Sometimes the truck shifts, and it goes back to 26k, sometimes it flashes up to 20k and bleeds back down to 4-5k then limp mode occurs.
I turned around and limped it back to the dealership, where try #4, they replace the CP3 again. I get it back, and limp mode again not 5 minutes after I picked it up. They want it back now to try replacing the ECM. I have had GM Customer Service involved now sing April of this year, and as of now,and they cannot figure it out. To sum it up, everything in the fuel system has been replaced, and now somethings twice. Any ideas on this one, truck was awesome before it got gasoline in the system. Its time to look elsewhere for the problem, so now they want to try replacing the ECM. I am going to suggest the fuel rail pressure sensor, sounds obvious to me, but what do I know. The truck all stock now except the exhaust and I can limp it by just hammering the throttle and not letting off until it does limp, generally by 85-90mph my fuel rail pressure gauge is dropping off and the CEL pops on.
Sorry for the lengthy post, but I have over a year trying to figure this out.

[weekendhauler]

Did you change the ECM? I have a 2008 2500 Duramax, I purchased in 2009, I have towed the same 5th wheel every summer. This July I was driving on I 70 in Denver and it went limp. It was 95 outside temp and engine was 210. It went limp 10 times at 55 to 70 MPH, up hill and down, in the next 90 minutes. The next two days it would go limp no less that 20 times on the road to Los Angeles. Dumped the 5th wheel and drove in LA traffic for 5 days in temps over 100, with no issues. Took the I 40 home and the truck went limp even when the temps we in the 80's or above. Hooked up the code reader and cleared the code when driving which takes about 30 sec, dropping 15 MPH but I did not have to stop. Just pressing the link button when you get the engine reduced power light, p0087 appears then hit clear code, the vehicle will maintain speed and in about 20 sec. full power is restored.

Reading all the past logs on this page and other pages, I was thinking the turbo is working big time pulling the 5th wheel and making heat and I wondered if the ECM was over heating and tossing the code. I do not buy the fuel temp because I cleared the code and kept driving and vapor lock would not clear that fast.

I was trying to think of a way to cool the ECM and take a day trip to see if it still tripped a code.

[Kennedy]

I have updated my Tech Tip:

http://www.kennedydiesel.com/docs/Duramax%20LBZ%20and%20LMM%20P0087%20Low%20Fuel%20P ressure%20code.pdf


Since my June revisions I have had zero reports of reduced power. Depending how bad the injectors are some still report a P0087, but all are able to drive right through it.

[Mark Rinker]

Great news. Interesting to see the # of hits on this thread, after almost seven years...never seen any problem resist a 'root cause resolution' quite like the "P00087 Low Fuel Rail Pressure" gremlin...

[Kennedy]

Root cause: excessive return flow from the injectors due to wear.

Cheap fix: Kennedy Custom ECM programming

Expensive fix: 8 new injectors

[a5150nut]

Root cause: excessive return flow from the injectors due to wear.

Cheap fix: Kennedy Custom ECM programming

Expensive fix: 8 new injectors

Or do both and be good for a lot longer!

[Mark Rinker]

Root cause: excessive return flow from the injectors due to wear.

Cheap fix: Kennedy Custom ECM programming

Expensive fix: 8 new injectors

Where does "Lift Pump" fall into that continuum? :rolleyes:

JK with all respect due, anyone that takes the time to re-read this nearly seven year long thread would deduce that it certainly WAS a long and winding road finally leading to 'root cause'. I'm glad that you stuck by your customers and finally found a programmatic solution for this problem! Congrats.

Glad its solved. Hope GM has/will incorporate better ECM programming in the future to allow for a wider range of injector return rates as the injectors wear over time.

[Kennedy]

Where does "Lift Pump" fall into that continuum? :rolleyes:




Mandatory for any Duramax in my opinion and experience.

[Mark Rinker]

Mandatory for any Duramax in my opinion and experience.

Your opinion is welcomed, your experience is deep and wide. Please explain


Why GM has sold millions of units since 2001 without a lift pump;
What is the accelerated outcome of not having a lift pump - i.e. premature CP3 pump failure, premature injector failure, global warming, etc;
Why it took seven years to arrive at a programmatic solution for the P0087 error code, if adding a lift pump was not the solution.


Curious, as I've been since 2009 when I first started this thread.

[Kennedy]

http://www.kennedydiesel.com/docs/Duramax%20lift%20pump.pdf

[Sirgrinalot81]

New to the diesel life and having some issues. I have an 2009 lmm 95000 miles keeps throwing p0087 and is going through fuel filters like 1 a month. Totally stock. Also have a lot of water in the fuel. Located in Kansas. I just ran it almost empty put seafoam in it and filled it up. Think I got a bad tank of fuel from caseys. Before it was throwing p0088 instead of the p0087. Any help is appreciated thanks

[Kennedy]

New to the diesel life and having some issues. I have an 2009 lmm 95000 miles keeps throwing p0087 and is going through fuel filters like 1 a month. Totally stock. Also have a lot of water in the fuel. Located in Kansas. I just ran it almost empty put seafoam in it and filled it up. Think I got a bad tank of fuel from caseys. Before it was throwing p0088 instead of the p0087. Any help is appreciated thanks

What I would recommend is a small bottle of FPPF Fuel Power to dry things up in your tank and then find a better fuel vendor or who spiked your tank.

From there my Tech Tips have the answers. On a daily basis I am "fixing" this with my pumps and tuning and will add that I am now hearing from a lot of "second round" guys who did the injectors and repeated shortly after or even immediately. The solution is still the same, still highly effective, and to me it just makes sense to do something that improves the system rather than just replacing parts with same.

P.S. I would NOT get hung up on water separators as many seem to be doing. You are one of the very few that has ever found any water in their systems

[CoyleJR]

I just returned home from four months on the road pulling our 38' 5th wheel. The truck and 5th wheel have a combined weight of 23,800 lbs and the temperature was often well over 100 degrees. My truck is a 2006 LBZ with 240,000 miles and this is the first time it has shown P0087 code. I found that if my fuel tank level was below half a tank, the temperature was over 100 and the truck was working hard pulling a steep grade it will throw P0087 code. I was able to repeat this problem code several times and fix it by opening the valve on my second fuel tank and adding fuel to the primary truck fuel tank. For 240k miles I have always kept the truck tank full by gravity feed from the secondary tank. This trip was the first time I let it get below half a tank of fuel. A full fuel tank must cool the hot fuel returning from the motor and that cool fuel keeps the truck from showing the P0087 code. I realize that there can be several causes for a P0087 code to show up but on my truck high fuel temperature seems to be the cause.

Additionally, I keep the small fuel cooler radiator in front of the fuel tank very clean and I am now considering installing a second fuel cooler on the right side of the truck.

[richp]

Hi,

Just returned to Illinois from Quartzsite towing the fiver. I have122k miles on an '09 LMM. No problems going down in January, but several 0087 episodes on return last week. Absolutely stock truck with auxiliary filtration and regular Power Service throughout its life. Regular filter changes. Regular Chevy dealer service at the same competent location. No lift pump (duly noted, John).

Obviously, working through this thread gives possible short and long term answers. But my solution for getting home the last 1,000 miles -- starting in western Oklahoma -- was to keep post turbo EGT's in the 1,000 degree range, and never more than 1,100. I used that as a proxy for the temps the injectors and incoming fuel were experiencing. I did this by doing a lot of manual gear selection on hills. I recall only one post in this entire thread that mentions that approach. Hmmm.

I will figure out my future with this truck somehow. But when other brands of diesels are notable for much longer injector life, it makes me wonder what GM has stuck us lifelong, committed customers with.

FWIW.

[richp]

Hi,

My dealer had it for two days, and as I expected, found nothing wrong -- injectors test solid, no codes left, and absent the load from towing heavy, on hills, while hot, no way to get their equipment to register my issue. They report all fuel lines solid, the fuel cooler clean, and no leaks anywhere.

These are two guys who know the truck since new, have serviced it thoroughly and regularly, and otherwise have my confidence. So for now I'm going to drive on and see what the future holds.

They did offer a thought that freeing up the exhaust might help keep overall temps down and thus keep the returned fuel cooler. Coming from a dealership, I found that interesting. Any thoughts on that from anyone?

[CoyleJR]

Hi Rich,

I agree with the dealer that opening up the exhaust would help cool the motor by lowering the EGT a little. I do not think it will get you a substantial drop in fuel temperature. Additionally, the noise caused by most large exhaust systems will make for a very long trip from Illinois to Arizona next year.

My post about the P0087 code was the one posted just before your post (take a look). If I keep plenty of fuel in my fuel tank it seems to cool the returning hot fuel and stop the P0087 problem. When your truck threw the p0087 code did you have over half a tank of fuel? I think a second fuel cooler would cool the returning hot fuel a lot better than a larger exhaust system. Just my thoughts on the P0087 code.

Good luck
John

[richp]

Hi John,

Thanks for the response.

I usually fill up at the end of the day's run with the fiver, so I can get a fast start in the morning. And I have been getting a few hours of clean performance -- until the tank is lower and the day is warmer. So refueling more often might help, although it would slow the day's progress.

I have pondered adding another cooler. Insofar as I recall, nobody in this thread has mentioned actually doing it, or a supplier with suitable hardware. So that is an option with dangling questions...

And yeah, the exhaust noise issue has occurred to me, and would be a turnoff. In addition to my own objection, I might never get Maureen to ride with me again. A very last resort, I think.

I appreciate being able to add your thoughts to the mix.