P0087 fuel rail pressure low limp under high loads

[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.