Truck surges smokes blue

efoster_01

efoster_01

They call me Bone
Joined
May 2, 2006
Messages
49
Don’t usually make it over to visit the D-Max guys but need some help.

A Co-worker has a 2002 duramax with a manual trans, ~72K Miles, the truck idles fine and under gentle acceleration runs well. However, under hard acceleration the truck jumps and bucks at 2000 rpm. Hooked the scan tool up and at 60% throttle the Fuel rail pressure drops to ~3k PSI while commanded is up around 17K PSI. It did not throw a CEL but it did trigger code P1093C (Fuel Rail Pressure Low During Power Enrichment. This problem presented itself the last time we had a cold snap, he replaced his filter but it warmed up the next day, turned cold again and its back. That was about a month ago. We fill up at the same station so I don’t believe it’s a fuel issue. That said I fill up at the high flow pumps and he has to use the auto diesel pump due to his smaller filler neck. The station only has one tank.

Thanks,
Evan
 
So it does it only when it's cold? Certainly eliminate fuel gelling as a possibility.

The fuel pressure regulator is known to be a "risk" part on LB7's. But there are several things that can cause fuel starvation, so throwing parts at can be pricey.

There is a schrader valve on the inlet side of the CP3 pump IIRC (LLY's have them so I assume LB7's do). Hook up a vacuum/pressure gauge there and see if it's a supply problem. If there is no vacuum, then it's probably the regulator.
 
Try running some additive, won't fix anything but might help it.
 
take a hammer and beat the inlet out of the fuel tank to make the high flow pump handle fit, we did this on our 99 PSD and it worked great!
 
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