I have a 2005 2500hd lly cc sb. Duramax tuner efi live, egr delete, pcv reroute, profab economy flow intake tube, 3" downpipe, 5" straight pipe exhaust, resonator plug, fass 150 titanium pump with the stock fuel filter assembly removed. I had an issue of surging at idle so I went ahead and installed a lbz fuel pressure regulator along with new tunes from duramax tuner. Going down the road the other night once the truck gets to 45-50 it starts surging or bucking at light to moderate throttle. Sent calibrated a datalog file that they are going to check into for me. Looked over the ficm wiring lastnight didnt find any breaks, checked over what sensors i could see as well as injector connectors and everything looks okay. Anybody have any ideas?
LLY surging
- Thread starter Yuptown_lly
- Start date
I know this may sound ignorant but I had similar issues. With my old lly. They went away when I fixed the wiring harness issue by the alternator. FWIW
What exactly was the wiring issue? I took the plastic cover off the ficm wiring behind the alternator as well as all the eletrical tape and all the wires looked good. Is there another spot to check?
I just ran a datalog at a somewhat steady throttle around 50mph, my commanded fuel rail pressure (FRPCOMM on the data) went to 0mm3 quite a few times. Is this an issue? Acutal and desired fuel rail pressure stayed about the same min 8992psi max 13052psi. FRPCOM has a min of 21% and max of 40%. FRPCOMM has a min of 0mm3 and max of 13778mm3. I'm new to all this so I'd appreciate any input! And as a side note throttle position read 10%-35% and speed 50-55mph. All other data seemed steady to me