GM Duramax 6.6L Diesel

Victor Technician Glendora, California Posted   Latest   Edited  
Unsolved
Driveability
2005 Chevrolet Silverado 2500 HD WT 6.6L (1 LB7) 5-spd (NV4500)
Lack of Power

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?

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David Diagnostician
Independence, Louisiana
David Default
 

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.

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Bill Technician
Rosetown, Saskatchewan
Bill Default
 

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.

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Victor Technician
Glendora, California
Victor Default
 

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.

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Bill Technician
Rosetown, Saskatchewan
Bill Default
   

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…

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