PDA

View Full Version : Noob with LB7 injector issue



Mr.Duck
September 12th, 2011, 09:53 AM
Loving EFI Live.


Buddy of mine has a 04 LB7, truck ran like a dream but started pressurizing the coolant system. He changed out the injectors, cups and head gaskets and associated hardware and gets the heads rebuilt. So he gets the engine running and it smokes like crazy, gray hard on your eyes, over-fueling diesel smoke. And it knocks, a diesel knock, not a rod knock.

So we tested the MAF sensor in the working LB7, it reads the same As the broken truck 35g/S I don't think your MAF is malfunctioning.
We shut down each injector 1 by 1. Injectors 6&8 make the biggest difference in the idle.
When we shut off injector 6 the smoke was reduced by more than half.
When we shut off injector 8 the knock went away.
I'm not sure if the injectors are peckered at this point, we think the problem is in the electrical system.
The truck seems to be in limp mode, it won't rev up past 2200 rpm.
We looked at the balance fuel rates on both trucks. The balances on the working truck are good and they are varied (0.69mm3 on the high end and -1.79mm3 on the low side.)

The fuel balance rates on the broken truck are reading ALL the same for all cylinders and are showing -155.66 mm3

So here is my question, if I can shut off and turn on each individual injector, why can't I get a decent balance rate reading?

Any input or direction would be appreciated and welcomed