GM Duramax 6.6L Diesel
I have this truck customer complains lack of power while towing no codes set. it has 6in of vacuum at the test port under load fuel pump actual and desired pressure, it can easily make 25000 psi. injector flow rates on scanner show plus or minus 5 on two different injector. I'm going to check the actual return rate from the injectors. My question is does any one know why the injectors would leak out excessive fuel, are they dirty ? worn out ? can the be sent to clean out or just plain have to be replaced?
These injectors tend to leak at the needle and seat. The seat erodes and the needle cannot close and seal properly. The leakage occurs to the return part of the system. The common rail systems work on high pressure-low volume. Any leak on an injector seat will warrant a replacement.
Victor, What do you mean under load? On the road with the pedal to the rug? That is the way you will want to stress the supply system. If it hits -12 in/hg it will fall on its face.
Yeah I hammered on it while testing it, and it has power everything looks good we both high pressure pump and low side fuel. But when the truck is loaded with a fifth wheel 8500 trailer the truck seems to not wanna go from a stop (trying to cross traffic) identifix has posting with the same scenario and the all lead to injector replacement.
Victor, I apologize, I have had a busy few days. How has this one been going for you? Were you able to duplicate the concern or are you going by the customers description of the concern? How did you make out with your return testing? Is this absolutely a code 1 LB7? Not the code 2 LLY? Flow (balance) rates can be affected by more than just leaking injectors. I believe this post has been…