P0087 fuel rail pressure low limp under high loads

[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.

[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]

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....