LLY throwing P1093, U1000, and C0035 codes and limping. Why?

[rollincoal333]

Hey guys, newbie here to diesel page. Im working on a 2004 duramax with the LLY in it. truck is a xcab long bed 2x4 with about 128,000mi on it. The truck would fall on its face under heavy acceleration and eventually limp to about 2000 rpm. However, no check engine light would show. So I plugged in my efi live v2 and got these codes:

PCM P1093- low fuel rail psi ,
DIC U1000- lost communication with ECM/PCM A ,
ABS C0035- left front wheel speed sensor circut malfunction.

I tried "the bottle test" to see if the fuel pressure relief valve was bad, but i only got a dribble of fuel from that. My "actual fuel pressure" was ranging drastically from high to low compared to my "desired fuel pressure" according to EFI Live so I just put a fuel pressure regulator on this morning and now the truck will last for about a minute of driving until it falls on its face under acceleration and limps again. Any advise or tips is greatly appreciated!

Thanks,
Bill

[Kennedy]

What is the fuel filter/system restriction?

I'd be inclined to ignore the other two codes. It seems that they come up on some 3rd party scans. I'd cross check with a Tech 2 if possible.

The bottle test should be completely dry, but it sounds like your valve may not be bad.

Important to note: People think that shimming and race valves are the answer here. This is NOT the answer. The problem comes from pressure cycling (pump can't match demand and then overshoots) which is resolved by clearing fuel system restriction, and adding a lift pump to keep teh fuel liquid and flowing well.

I do believe that we are seeing a pattern emerge. North of 100,000 miles with factory filtration, no lift pump and crappy fuel seems to be taking it's toll. More LBZ's for some reason, but the LLY are in there as well.