P0087 fuel rail pressure low limp under high loads

[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.

[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.

[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.