LB7 power loss

[Oldsalt]

I have a 2002 2500HD Duramax I purchased new for daily driving and ocasionally towing a 12000 lb 5th wheel camper. Only problem other than normal maintainance was a water pump change at 110,000 miles. I left south Louisiana towing the camper and all was well until I exited I 20 at Tyler, TX. when I tried to accelerate from the stop sign I had no power, the engine actually died but easily restarted. I had truck towed to Chevy Dealership in Tyler the tech said I had a low rail fuel pressure trouble code and my fuel filter was plugged, This was a new filter installed just prior to the trip.
Thinking I may have gotten some bad fuel at a stop 100 miles prior to problem starting. I authorized them to change the filter, clean injectors and put additive in fuel tank to the tune of $432. I watched as he drained the filter and saw only clean fuel come out No trash or Water
I was on my way again when I encountered a grade that caused a downshift, I immediately had no power to pull the grade
Got the rig off the road and called Tyler Chevy The insisted that it was dirty fuel and offered no further assistance.
At this point we cancelled our trip and limped home.
The truck runs fine without a load and will pull the trailer fine down the interstate at 65/70 mph If I have to stop for any reason I have no pulling power and have to nurse it up to speed, if the transmisson downshifts while pulling a load I have no power. The truck starts and runs good no smoking no missing

[Mark Rinker]

Some questions:

How many miles on the truck?
Are these the same miles that are on the injectors / injector pump / and fuel pressure regulator?
Is the check engine light illuminated? If so, what are the codes retrieved?
Any smoke at the exhaust under acceleration?It sounds like a fuel delivery problem. Since you have effectively eliminated fuel filter restriction as a problem, it points to fuel or fuel delivery componants.

Any chance that your last fillup wasn't #2 diesel, but unleaded gasoline? How many gallons of fuel did you add, 100 miles before the problems started? Was it at a BP station, with the dreaded green handles? I have made this mistake once, to the tune of ~24 gallons unleaded fuel on top of the remain ~8 gallons of diesel. I drove the truck for almost 80 miles before first noticing the problem after the first stop. My first thought was a plugged fuel filter, I didn't even notice the gassy smell until I replaced the filter and the truck would not easily restart. Also - the truck had very little power once stopped, but would run fine once up to speed - i.e. under minimal acceleration load. Check your last fill receipt to verify the cost/gallon you were charged, if you still have it. Also you can drain some fuel from the petcock on the bottom of the fuel filter and smell it;If you are sure that you have good #2 diesel in the tank, AND there is no odd smoke at your tailpipe, you may be experiencing the failure of the high pressure (injector) pump, but that would probably be setting some codes and the Check Engine light.

[rapidoxidationman]

I'm curious as to exactly HOW the stealership "cleaned the injectors" on that LB7 for anything less than the labor involved in removing the valve covers... and if the fuel was suspect, why didn't they drain the fuel tank?

[markelectric]

I have had a similar problem with my 01. Mine seems to be heat related in the fact that it only did it when the outside temp was over 90 deg. I got a bad load of fuel in the Jan 2010 and froze the truck. EVERY fuel line that we could see was sucked flat at that time. Summer of 2010 the low power started. At the time in the summer I too thought I had a bad load of fuel. I could change the filter and get a bit over a hundred good miles of towing out of it when the power faded away. By the third filter (each one being dumped and nothing but clean fuel being seen),I realized something else was causing the problem. I can only assume that I have a bad line somewhere that gets soft with the heat and will go flat when a bit more suction is applied. I bought one of Kennedys fuel lift pumps last fall right after my busy season was over and because of the "dreading to lower the tank" I did not install it untill last month. I have towed many trailers thruout the fall, winter and spring but with the cooler temps, I have noticed no problem. My busy season is on now and because of the need for some wider goosenecks hauled first the Chevy shortbed has not been a part of the mix yet. With the heat now it would be a good test. By end of next week it will have to be on the road with a load.

Was that a definitive answer to your problem?......No But with what I felt last summer and the research I did I think I am ready to try to tow again.

Good Luck

[Oldsalt]

Some questions:

How many miles on the truck?
Are these the same miles that are on the injectors / injector pump / and fuel pressure regulator?
Is the check engine light illuminated? If so, what are the codes retrieved?
Any smoke at the exhaust under acceleration?It sounds like a fuel delivery problem. Since you have effectively eliminated fuel filter restriction as a problem, it points to fuel or fuel delivery componants.

Any chance that your last fillup wasn't #2 diesel, but unleaded gasoline? How many gallons of fuel did you add, 100 miles before the problems started? Was it at a BP station, with the dreaded green handles? I have made this mistake once, to the tune of ~24 gallons unleaded fuel on top of the remain ~8 gallons of diesel. I drove the truck for almost 80 miles before first noticing the problem after the first stop. My first thought was a plugged fuel filter, I didn't even notice the gassy smell until I replaced the filter and the truck would not easily restart. Also - the truck had very little power once stopped, but would run fine once up to speed - i.e. under minimal acceleration load. Check your last fill receipt to verify the cost/gallon you were charged, if you still have it. Also you can drain some fuel from the petcock on the bottom of the fuel filter and smell it;If you are sure that you have good #2 diesel in the tank, AND there is no odd smoke at your tailpipe, you may be experiencing the failure of the high pressure (injector) pump, but that would probably be setting some codes and the Check Engine light.


all components on engine with the exception of water pump are original, truck has 135000 miles. Have used mobil 1 synthetic lubricants in engine and transmission since first oil change.
the check engine light did not come on but tech at dealership said i had a low fuel rail pressure code. the check engine light did come on twice while I was limping home but went out after a few minutes and I haven't checked for any new codes.
No smoke at acceleration and engine runs fine when not pulling a load.
I think the fuel is OK. I have two tanks and was running on the aux tank.
when I stopped for fuel I switched to the main tank. I put two gallons in the main tank and filled the aux tank. Fearing I did have bad fuel I did not use the aux tank returning home. I drained some fuel from the aux tank when I got home and it is fine.
One thing I forgot in my original post, when the tow truck operator was disconnecting my driveshaft he noticed some kind of oil coming from the top
of the transmisson. The chevy tech said I had probably overfilled the engine oil when I changed it and with towing it was coming out the vent.
Also the oil when I returned home is very dirty. I have a 1 micron bypass filter that removes most of the soot normally but this oil is very sooty

[JohnC]

The chevy tech said I had probably overfilled the engine oil when I changed it and with towing it was coming out the vent.
Also the oil when I returned home is very dirty. I have a 1 micron bypass filter that removes most of the soot normally but this oil is very sooty

How much oil is in it? Is it diluted with fuel?

[markelectric]

Ok since I posted earlier I rescheduled a load just to test the pump idea. Same manlift that was on the trailer when the problem occoured almost a year ago. Different trailer, got rid of the 24 ft tag and now using a 28ft goose, both open and low deck style, On similar interstate and hotter temp outside.

Wife was driving (then and now) all went well with the tow. It seems like the lift pump cured the problem.

New problem. Due to the way I need to move trailers, I have been flat towing my 2500 Dodge home behind the 3500 Dodge. Since I used the Chevy, I put it on the trailer for the return trip. When I stopped for fuel, I noticed a fresh oil stain on the trailer deck. It appears that the oil pressure switch that had to be added for the pumps is leaking. I am not sure if it is the switch itself of the fittings leading to it, all I know I had a hell of a time getting that thing in there.

I guess I have another cussing session ahead.....

[Oldsalt]

How much oil is in it? Is it diluted with fuel?

the oil level was slightly above the full mark and very dirty the bypass filter that is installed keeps the oil clean and I had just changed oil and fuel filter'
As for being diluted with diesel I dont know, How do I tell.

[rapidoxidationman]

How does it smell?

How's the viscosity compare with known pure oil?

or the pyro's method:
How quick can you catch it on fire? ;)

[Oldsalt]

How does it smell?

How's the viscosity compare with known pure oil?

or the pyro's method:
How quick can you catch it on fire? ;)

I am away from home at the moment will return at the end of the week.
I will check for new codes and diesel in the oil.
if there is diesel in the oil I am assuming this means I have injectors leaking.
Is that your prognosis?

[rapidoxidationman]

That's sure what it sounds like, given all the factors (LB7, 135K miles, overfull oil) but I'm not an expert. Might be worth the $$ to connect the truck to a techII scanner though.

[DmaxMaverick]

If you have fuel in the oil, a Tech II won't tell you any more about it than what you already know, the PCM is having trouble maintaining rail pressure. This can be caused by several issues including fuel filter plugging, collapsed fuel line, failed fuel filler cap, fuel injector leak, return line leak (internal or external), FRP regulator failure, pump failure, fuel contamination, or a suction-side fuel system leak (not in any specific order). A fuel system return rate test can't be performed "hands off" (with a computer/scanner), and requires a specific procedure to measure the return volume. Not difficult, but in no way "simple".

You can check the oil for fuel contamination easily. Engine at operating temperature, shut down and wait 5-10 minutes. Using a thin, white paper towel or coffee filter, pull the dipstick and allow the oil to puddle on the paper (don't wipe it). If you have fuel in the oil, it will have no problem running off the dipstick and onto the paper. If it's thick and won't "abnormally" drip onto the paper, you probably don't have fuel dilution. After about 5-10 minutes, examine the "ring" of the oil drop on the paper. Oil will create a distinct dark(er), heavy ring. Any fuel in the oil will create an outer ring stain on the paper, much lighter and thinner. Usually, by the time you have enough fuel leaking into the crankcase to cause running and/or fuel system codes, it will be significantly more than a "little overfull", and ultimately, it will dump excess volume out the PCV pipe below the engine, which will make a huge mess under the truck and coat the tailgate and a trailer you may be towing. It's quite obvious at this point.

Heavy, dark, thick engine oil may indicate another problem. If you are within a reasonable service interval, your bypass filtering system has failed, or you have another source of contamination. Excess sooting is usually the cause, and is not uncommon with some heavy power tunes (chip).

Start with the simple or cheap/free things you can check, and eliminate them as you go.

[Oldsalt]

That's sure what it sounds like, given all the factors (LB7, 135K miles, overfull oil) but I'm not an expert. Might be worth the $$ to connect the truck to a techII scanner though.

Arrived home last night and checked trouble codes. Found the following three
P0087
P0234
P1093

The oil level is about 1/2 inch above the full mark, Haven't checked for presence of diesel but suspect that it is, No Smoke when running. I am going to change oil and filters and take to mechanic.
Question, I understand when nozzle starts leaking you will get smoke. But what is leaking when the diesel goes into the oil is it the seal between the injector and cup or what.
Truck runs fine when not pulling the 5th wheel

[DmaxMaverick]

I don't suggest jumping to that conclusion, just yet. 1/2" above the full mark is still within the margin of error for a fill, and will have little, if any, affect on driveability or other noticeable concern. Have the oil tested to confirm the presence, or lack of fuel contamination. Blackstone Labs and Amsoil offer inexpensive test kits. Both return results very quickly, and will notify you by email, or a phone call, with any alarming results. Be sure to indicate on the test form you have a fuel/oil concern, and they'll let you know as soon as the results are available.

Fuel can enter the crankcase in 2 ways. The most common is a cracked or unsealed return line (under the valve cover). A close second is a cracked injector body. Neither of these will cause smoke until you have a LOT more than a 1/2" overfill, and by that time, you should notice a drop in oil pressure. The engine will also idle and run rough (no air space in the crankcase). Shortly after, it will soak the underside of the truck, bumper, tailgate, and any trailer you may be towing, with fuel/oil.

Your codes indicate:
Low fuel rail pressure
Turbo overboost
Large fuel system leak

If you find fuel in the oil, the fuel system codes indicate injector failure.

Your power loss is probably related to the overboost. When this occurs, the engine will defuel (causing power loss) and a stored DTC (P0234). The SES may come on, and in most cases, power will return to normal after about a minute of lower power driving or a restart. This is most often caused by aftermarket modifications that interrupt the wastegate control, damaged/disconnected wastegate control hose, or damaged wastegate actuator or linkage. If you have no such aftermarket boost controller (valve, blocker, etc.), check the rubber hose connecting the turbo compressor to the wastegate actuator. If you are using a boost controller, adjust it down, or remove it if it isn't adjustable (the non-adjustable ones are junk). The OEM wastegate control is 100% automatic and independent of any other system or PCM input. The wastegate is spring-loaded closed, and it is opened only by compressor output pressure to the actuator. The PCM controls boost levels via fuel mapping.

[Kennedy]

Dmax Mav has you on the right track here, but jumping to conclusions it sure sounds like a cracked injector(s) issue. Thing is, I'd expect more volume in the crankcase.

I'd check system restriction first. Could be another loaded/plugged fuuel filter. The fuel system restriction is the first place to start with 1093 and 0087 diagnosis, and rather than just changing teh filter I would suggest that you test restriction to see what it is. A filter can load up VERY quickly with a bad tank of fuel. and put you right back to square one.

[Oldsalt]

Dmax Mav has you on the right track here, but jumping to conclusions it sure sounds like a cracked injector(s) issue. Thing is, I'd expect more volume in the crankcase.

I'd check system restriction first. Could be another loaded/plugged fuuel filter. The fuel system restriction is the first place to start with 1093 and 0087 diagnosis, and rather than just changing teh filter I would suggest that you test restriction to see what it is. A filter can load up VERY quickly with a bad tank of fuel. and put you right back to square one.

I spoke with one mechanic I trust (He was a diesel mechanic with GM before going out on his own). He is pretty sure it is the injectors but would need to run some tests first. I changed the oil drained close to 11 qts and changed
both oil filters The bypass filter was plugged dirtier than I had ever seen it.
Filled with new oil run it to operating temperature, let it set for 1/2 hour checked and noted level on dipstick I will monitor for an increase in level.
While I was under the truck I noticed oil blowback along the chassis coming from rear of engine and top of transmission.
What is a nominal charge for injector replacement I have been quoted 4-5 thousand from independent and 7-8 thousand from GM.

I have been told to get another one by my wife, She has never said that before in 51 years of marriage. I am thinking I should take the offer.
Reading this blog is seems that models with the LBZ engine are the best, but I would like to find something a little newer with a year or two of factory warranty left. That would be the LMM models. What are the major differences and how is performance/mileage affected? I suspect the main differences are emission controls? Ant input from all you D/M fans would be appreciated.
I always said I would rather push a Chevy than ride in a Ford and for the first time it almost happened