P0087 - FPR replacement

[Mark Rinker]

The fuel line fix did not improve my ongoing P0087 issue while towing heavy and running hills. After resetting this code too many times to count yesterday, I am on a path to replace the FPR this weekend, before dragging this big boat throught the mountains west to WA state next week.

I have searched, but not found a recent thread by someone who sourced the FPR through GM Parts Direct, and did the swap themselves. If you are this person, and reading this, please give me a call at 612.578.6355 or PM me a good time and number to give you a call. Have a few questions for you.

(Jim/Greg if you know which recent thread I am referring to, please post the link here....thanks! For some reason, I can't find it this morning...it probably has more to do with no coffee left in my room, than any other factor...)

[HMSW]

I changed mine yesterday. Bought from Oregon diesel and shipped overseas.

It is tight where it is located, but possible. Have some different torxz 25 avalible together with a magnet and you will get a long way ;)

I guess you know how to get to it?

I removed ac compressor, some cables, some hoses and the top of the thermostat housing.

Good luck

[Mark Rinker]

Thanks for the info...did you have idle surging, codes set, or...?

[Kennedy]

The term FPR best fits Fuel Pressure Regulator. This regulator seldom goes bad without surging, etc. I have been in contact with people chasing this P0087 who have changed thousands of dollars in parts and not fixed it. About the only one that I have heard that fixed it replaced the injectors which I had suggested is likely the underlying issue.


There is also the FRPR. This is a poor use of term for teh relief valve as it could be confused with the regulator valve. I just call this the safety or relief valve. In normal operation this should not cause issues, BUT pressure cycling can hit this valve and after hit a few times it can weaken. If it were weakened you'd likely never reach max psi.

Reality is that IF this valve is leaking and you replace it, shim it, etc you are only treating the symptom. You will still have pressure cycling which is a product of insufficient supply/air in fuel. Insufficient supply/air in fuel is caused by loaded filter(s), kinked lines, increased demands of heavy towing, high injector return rates, etc. To test this pull off the small hose from the rail and plug it. Add a new hose to the rail and run to a bottle and do a bottle test. That or take uit to teh dealer cold. Start it up and have them ramp the rail pressure to max. Feel the end of the rail (carefully) for heat. It will get HOT very quickly.


Insufficient supply is cured by adding a lift pump setup which ALL Duramax engines should have. We are right back to verifying the condition of the fuel supply system and also augmenting it with a little push from behind.






I wonder if GMPartsdirect has a tech line?

[Mark Rinker]

Thanks for the input, John. You have been a wealth of insite over the last year and 50K miles since this problem began. I wish you had the opportunity to ride along and see the circumstances under which the code is set.

It appears to me from the handful of recent reported cases (of P0087 codes) that each scenario is a bit different, which would lend itself to a combination of multiple factors - i.e. tired injectors, erratic FPR, weak FRPR, collapsing fuel lines, etc.

I know of one commercial hauler that fixed the issue with fuel line replacement. Recently another person here on TDP reported that an FPR replacement did the trick for him.

At this time, I have moved the FRPR down the list of likely culprits, because my codes can be set at 16K# rail pressure, or 22K# rail pressure. My IP and rail can also hold 23K# rail pressure for minutes at a time while climbing an 7% grade, in third gear at 45mph, 3000rpm without setting the code. Upshift to 5th and let RPMs drop and 'Engine Load' hit 100% - and 'bing' you have a P0087. Which gear and throttle setting requires more fuel flow?

Its not as simple as it may appear, or we'd all have solved it in the same manner, with the same part. Or, lift pumps would come from the factory on every new GM Duramax truck.

...or...


Insufficient supply is cured by adding a lift pump setup which ALL Duramax engines should have. We are right back to verifying the condition of the fuel supply system and also augmenting it with a little push from behind.

...are you confident enough that adding a lift pump would have cured all the p0087 code problems mentioned above, i.e. overcoming fuel line restriction, FPR problems, weak/worn injectors, etc? If so - are you willing to sell your lift pump on those terms, refunding and restocking if the lift pump doesn't solve a customer's particular problem?

Question #1: Why did the truck function properly for the first 100K miles, in stock form, before starting to exhibit the p0087 code problems? i.e. what changed?

A: Wear and tear. Probably injectors, plus FPR, possibly fuel lines

Question #2 How many times can you reach up and reset the code, while driving in hot weather, in the mountains, with a loaded trailer, for the cost of a new set of injectors?

A: Many, many times in my case.


I'll tell you what you could sell alot of - that would be an ECM reflash to widen the tolerance for fuel pressure variances, or set the code without the limp. Remember - nobody reports a driveability problem, other than the one created by the limp mode!!!

;)

[Kennedy]

I've said this numerous times. There are 3 keys to a healthy happy fuel system. They all revolve around fuel quality.

1) Filtration-it just needs to be better in most cases. A secondary filter is highly recommended.

2) Lift pump- keeps the fuel liquid AND greatly improves the efficiency of your filtration. Also removes some of the workload from the CP3.

3) Quality additive-FPPF Total power in every tank. Cleans, lubricates, safely removes water, improves combustion.


These are not gurantees, but sure go a long way to a healthy happy fuel system. Unfortunately they should be implemented early on and not at 130k after the onset of trouble.


Eventually I hope to have something in tuning to help this, but until then...

[Mark Rinker]

Eventually I hope to have something in tuning to help this, but until then...

...buy a Kennedy Diesel 1) mega filtration system, 2) lift pump, and 3) case of FPPF !

:D

[Kennedy]

I'm not your typical salesman in that I often talk people out of doing some things like bombing their Dmax's. When I push a product there is a definite reason. These trucks run SO nice with a gentle push on the fuel system.

[More Power]

An old stand-by troubleshooting test developed here in The Diesel Page more than ten years ago, for the 6.2/6.5, to help determine whether a stalling/low power/hard start problem might be due to worn fuel injection system parts is to:

Once the fuel level in the tank is down to about 5 gallons, create a mix of 4.5-gallons of diesel fuel and 2 quarts of 30W motor oil in a separate fuel container, and pour it into the tank. This will result in a 5% oil mix in the fuel tank. If the added fuel viscosity temporarily solves the problem or lessens the symptoms, you've learned something. Worn parts are the likely problem. Once the troubleshooting is complete, fill the tank with straight diesel.

The oil won't hurt the engine or fuel injection system, but I'd not do this in a 2007+ truck equipped with a diesel particulate filter in the exhaust system.

If increasing fuel viscosity helps, you have a choice of either replacing the high pressure pump or injectors. I'm not sure whether the FPR would be helped by added fuel viscosity.

Jim

[Mark Rinker]

Update: Took the boat/trailer out for a test run this morning, was able to reproduce the P0087. On the bright side, the lopey idle is now gone thanks to the FPR replacement.

So, today I plumbed in a lift pump along the driver's side frame rail in the open, available space just ahead of the fuel cooler (Yes I know those are the small diameter return lines to/from the cooler, the large supply line is there, too ) and behind where the antilock brake controller lives. We'll see if it makes any difference - if it does, I'll eat a big slice of humble pie for not installing it, first.

Probably just as Kennedy first theorized - ball/seat erosion on the original sprays at 150K miles. If thats the case, and none of the three known remedies (installed in combination) fix the problem, I'll continue to push the SES reset button in the summertime, loaded, and in the hills.

Somebody is going to code around this problem eventually.


:o

[Mark Rinker]

An old stand-by troubleshooting test developed here in The Diesel Page more than ten years ago, for the 6.2/6.5, to help determine whether a stalling/low power/hard start problem might be due to worn fuel injection system parts is to:

Once the fuel level in the tank is down to about 5 gallons, create a mix of 4.5-gallons of diesel fuel and 2 quarts of 30W motor oil in a separate fuel container, and pour it into the tank. This will result in a 5% oil mix in the fuel tank. If the added fuel viscosity temporarily solves the problem or lessens the symptoms, you've learned something. Worn parts are the likely problem. Once the troubleshooting is complete, fill the tank with straight diesel.

The oil won't hurt the engine or fuel injection system, but I'd not do this in a 2007+ truck equipped with a diesel particulate filter in the exhaust system.

If increasing fuel viscosity helps, you have a choice of either replacing the high pressure pump or injectors. I'm not sure whether the FPR would be helped by added fuel viscosity.

Jim

If the lift pump doesn't solve the problem when added to the fuel line and FPR replacements, I'll probably be trying this on the way west to Blaine, WA this week, just for entertainment.

;)

[Kennedy]

So, today I plumbed in a lift pump along the driver's side frame rail in the open, available space just ahead of the fuel cooler (Yes I know those are the small diameter return lines to/from the cooler, the large supply line is there, too ) and behind where the antilock brake controller lives. We'll see if it makes any difference - if it does, I'll eat a big slice of humble pie for not installing it, first.



:o

Three major tossups here. Is it high enough volume, will it last, and when it fails will it leave you in trouble until removed?

I have a pretty good hunch, but what do I know?

[Mark Rinker]

First test (before leaving home) was to verify that the truck loaded with boat/trailer would get enough fuel to operate, with pump inline and not powered up...

First two days out this week through ND and MT it appeared the addition of the lift pump had made a significant difference in reducing/narrowing the window where the p0087 code was set. This was in 70 degree, moderate rolling hills.

Day three through mountains of MT, ID, and WA sometimes in 90+ heat it was apparent that nothing short of a new high pressure pump and possibly 8 new sprays would return this 150K truck to its original towing capabilities.

The reason I am now leaning more towards a weak high pressure pump being my root cause of the high demand fuel temperature increases, p0087 codes, etc: Under high load and high fuel demand, at high RPM operation (3rd gear, 3000rpm, 45rpm uphill mountain grade) it can keep up and make 24K# pressure, but on the same hill, upshift to a higher gear, (letting pump driven RPM drop) - that is where the code and limp then occurs...(this can be very problematic when ascending a grade, loaded, by the way.)

What shape the injectors and high pressure pump would be in today, had it been given a full compliment of fuel system upgrades, is anybody's guess. I'd say its very likely that additional fuel pressure in my case could have extended the livespan of the high pressure pump. Never had a problem with one in all the DMax's owned, so its a new experience for me.

In under two years of my ownership, the truck has delivered 100K brutal towing miles, with the constant being large, wind resistant loads of 25K# GCVW and more. If you consider the amount of fuel that has been pumped through the system, the 'wear and tear' on the truck's fuel system could easily be double what shows on the odometer of other trucks. Based on this last experience and (very unscientific) tests, at a minimum I'll be plumbing in a lift pump from the outset to help the high pressure pump do its job easier.

Sitting down with fork and slice of humble pie. :)

[Mark Rinker]

Another componant in the fuel delivery system, that has never been discussed as a possible contributor/cause. Certainly codes would be thrown by the ECM if this box wasn't happy. On this trip, I have seen a 'U' code without description...more on that, later...

(LLY unit shown for illustration and useful text purposes only)

http://cgi.ebay.com/ebaymotors/Fuel-Injector-Control-Module-FICM-2004-2005-Duramax_W0QQcmdZViewItemQQ_trkparmsZalgoQ3dSIQ26it uQ3dUCIQ252BUAQ252BFICSQ26otnQ3d8Q26pmodQ3d2005045 14475Q26poQ3dLVIQ26psQ3d63Q26clkidQ3d6593676733760 113954QQ_trksidZp3907Q2em263QQcategoryZ38636QQitem Z160455552145

[cabletech]

Mark

You don't have a FICM. They are only on 2005 and older trucks. GM went to the Bosch ECM to get rid of the FICM.

Jay

[Mark Rinker]

Thanks! I was looking for the familiar box on the passenger side yesterday, and couldn't see one. This explains it...

Yesterday's trip from Bothell, WA up to Blaine, WA to deliver the boat went well. Cool, 65F air makes a world of difference, the truck never gets hot under the hood where everything (engine, trans, cooler stack, fenders, core support, hood) is HOT HOT HOT and the truck just can't get rid of the heat fast enough.

The trip Thursday from Bozeman, MT to Bothell, WA was a thrash...680 miles, three major mountain passes, 90+ degree temps, and 25K# GCVW in 14hrs...probably the most epic day I've put in behind the wheel.

[Kennedy]

Three major tossups here. Is it high enough volume, will it last, and when it fails will it leave you in trouble until removed?

I have a pretty good hunch, but what do I know?

Not knowing system restriction and what the pump is doing under load does not help diagnose the situation.

[Mark Rinker]

Unless there is a componant that is 'thermally variably restrictive' in the fuel system, then I am still very certain that excessive fuel temperatures contribute primarily to the low rail pressure codes I am experiencing. Fuel has to reach 180F or greater in my case for the p0087s to begin to occur. The day after having major issues in the mountains at 90F+ outside temps, I ran from Seattle to Blaine in mist and fog at 65F with no issues. Multiple full pedal accelerations in 4th gear confirmed that the pump could make and hold 25K# psi rail pressures, with cooler 140F fuel and overall cooler underhood operating temps.

If it were a constant restriction or lack of flow problem, it would occur under similar loads, independent of ambient temperature, or fuel temperature.

It also would have likely occured in the first 100K miles of duty, in stock trim, under similar temps and loads...whats changed? (...weak high pressure pump, weak injectors...)

[Kennedy]

How do you know if your lift pump is keeping up?

[Kennedy]

Working on a few different tuning scenarios to try and skirt the issue with Mark's truck. I think I can find a way around it, but only time will tell.

Spoke with yet another LBZ owner with only 77k on teh clock and NOT used for a lot of towing. He's having the same problem. He found a major restriction (22"hg) in his fuel system from a hose that was pinched when an aftermarket tank was installed about 3 years ago. Fixing the restriction DID NOT cure his problem. My gut tells me that he's been running severely restricted for years and processing lots of air which in turn has taken it's toll on the fuel system. Even with normal restriction the fuel system has a lot of air in it and it's just not a good thing.

This is why I push lift pumps and the restriction gauge so hard.

[Mark Rinker]

Another observation - of many:

Today I had work done on my son's 2004 S10 Blazer. According to the tech, the fuel filter was "severely restricted" and "the junk that came out of it was black." We recently bought this truck with 150K on it. Aside from poor mileage, the truck was running fine. It was probably the stock OEM filter... :eek:

The comparison to a 4.3L gasser stops there, but consider if the Blazer's ECM was concerned with rail pressure enough to set a check engine light and limp the truck. The fuel filter would have been changed long, long ago.

In my thinking, GM engineers and EMC programmers have stepped on it with on this one, because their test mules didn't consider the myriad of circumstances can cause low rail pressure, including but not limited to:

Restricted fuel filters (obvious and purposeful cause for the limp)
Crimped, collapsed, or restricted fuel lines
Hot, thin fuel
Weak or work injectors
Weak or worn pump
High fuel demand, combined with one or more of the above!!!#6 will almost always be a transient condition - where the limp mode is counter-productive to driveability...i.e. stranding a loaded 5-er on some grade climb out of Denver. NOT GOOD.


The sooner somebody programs around the limp, and sets the SES as an 'informational' message, the better. Just like the venerable LB7s...run until they choked.


My .03 worth!

[Dinkie Diesel]

I just replaced my FPR valve today. My 2001 has had the idle funk for a long while and I was getting tired of it. I read all I could before tackling it. Now that it's done and I know and have the right tools I think I could do it again in an hour or two. I happened to have one of those long 90 degree screwdrivers for adjusting the carbs on motorcyles. What a life saver that was. Still managed to drop a screw in the valley. Ended up going to Lowe's and replacing them all with hex cap screws even though I still have 2 of the originals. Didn't remove the bridge. Just the neg. batt cables, A/C compressor, alternator wire, three electric connects, water housing, hard piped water, and two fuel hoses. Acces wasn't easy with fat paws. My Craftsman 1/4" drive ratch wasn't of the fine tooth type but it worked.

The bracket that attaches to the driver side valve cover to hold the hard water pipe has a bolt under a huge wiring harness. I removed the bracket to get the pipe out of the way. After I installed the new FPR I started the truck to make sure it would start before re-attaching this bracket and filling the radiator. It started fine. No hiccups. I smiled!!! In order to get that bolt back into the bracket under that wire harness I flipped the gray lever which unplugs that harness and allowed me to move it slightly, enough to get the bolt started. Like a dummy, I forgot to flip the gray lever again which locks the harness in contact. I jumped in to start it again after buckling everything back up except this gray lever. The truck wouldn't start. I got worried. Then it dawned on me I forgot to flip the gray lever and plug that harness back together. It started after doing so but now the Service Engine Light is on. I tried undoing the batteries hoping it would reset. It hasn't. Any recommendations?

BTW, the idle funk is gone. Yippee!!!

[DmaxMaverick]

To reset codes, disconnect BOTH batt+ cables and ground one to chassis (the cable, NOT the battery). Or, if you already have both battery ground cables disconnected, jumper a ground to a batt+ cable. In either case, the battery power must be disconnected, as if the batteries weren't in the vehicle. Come back after 30 minutes and reconnect. The computer should be reset. Some may work in less than 30 minutes, but that's the shortest time I've had reliable success. If you don't ground the cable, it can take overnight, or longer, to reset. Just did one this morning. It clears all computers, TCM and BCM as well (essential after ABS or SRS faults, which take a really looooong time to self-clear).

[Dinkie Diesel]

Thanks Maverick! That worked! Light is out. Why I waited 2 years or more to do this I'll never know. It's like have a new truck again.

[Kennedy]

For the LBZ's out there plagued with the P0087 I believe with reasonable certainty that I have conquerred it. Still need to test this with an on road vehicle, but I fixed on a Pull truck yesterday. This truck has dual CP3's and freshly tested/calibrated performance injectors.

This will be available in my Kennedy Custom ECM Programming. LMM still work in progress.

[Jim Schroer]

I believe I have the same issue as Mark, I have an 09 with 100,000 miles that I just got back from the dealer with a diagnosis of bad injectors due to high return flow. They tested the high pressure pump and it passed so they assume injectors. Please contact me if you have found a way around replacing the injectors.

[Kennedy]

I'm doing a LBZ tune for a shop in IL that has several different Dmax trucks sitting sidelined due to chronic P0087 code issues. I should know more soon.

This issue kicked my ass on the dyno the other day, but eventually I prevailed.