LLY bad injectors?

bigjake18

bigjake18

Member
Apr 2, 2013
85
0
6
college station, tx
A buddy of mine has a lly duramax and got some bad fuel one day, at least thought was bad and the truck was running rough then wouldnt start back up. well the fuel system wouldn't prime and he ended up takin it to a shop where the people there mainly know cummins and can barely fix them but his boss made him take it to that shop, they replaced the fuel filter housing and the piece that slides down into the tank due to it falling apart into the tank after inspecting it. The fuel system holds prime now but only way the people at the shop can start it is if they put a rag with gas in the intake. After it starts and motor is warm runs fine and no knock or bad balance rates. Turn it off and right back on it starts fine. Only after it sits awhile it needs the gas rag to start up. Mechanic said the injectors are bad and it's leaking fuel while trucks off causing this problem and making it lose prime also. Could that be the case, faulty injectors?
 
J

jc1843

New member
Sep 27, 2009
228
0
0
86
So Calf
First you need to check the fuel rail pressure, and the desired fuel pressure, and compare the two. If an injector is stuck open, it will reduce the rail pressure and be hard to start.

You could also check for fuel leaking out of the driver's rail nipple, where the "U" shaped hose connects. If fuel comes out the nipple when cranking/running, the FPRV is leaking. [it screws into the back of the driver's rail]

Also be sure to check this common LLY problem--At the side of the alternator, the FICM harness tied down with a Zip tie. Cut the tie and pull the wires from the harness and inspect for cuts and wear. The sharp corner of the FICM bracket where it is tied down to, cuts into the wires. Repair and insulate the harness with a short piece of heater hose.
 
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