loping after fass 95 install and injectors

MarylandDmax

Member
Jan 30, 2016
36
0
6
so i just got done doing injectors and a fass 95 install, and the truck is loping most noticeably when coming to a stop. i have watched the desired vs. actual fuel rail pressures and when the truck is warm they are close, and the actual is +/- 2 psi. when i first start the truck the actual is much much higher than the desired. when i did my fass install i did a factory fuel filter delete from fass and installed a gauge there. when the truck is at idle the gauge bounces around like crazy, so i dont know if it is my FPR or inconsistent flow from the fass.
 

MarylandDmax

Member
Jan 30, 2016
36
0
6
So I talked to fass, adjusted the pressure down and the fluctuating pressure is gone and steady at 9 psi
 

Ridin'GMC

I like red
May 20, 2010
645
22
18
MA
LB7 do not like high lift pump pressure, it causes them to lope any higher than 10 psi. The LBZ can run at 14 psi without any lope issues.
 

kidturbo

Piston Tester
Jul 21, 2010
2,552
1,400
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Somewhere On The Ohio
www.marinemods.us
X2 on the 10psi cap... However I never knew that about the LBZ and 14psi without issue. Learned something new today. Must be that diff regulator design.

I successfully ran 12-15psi on the LLY boat engine after remapping the reg curve a bit, and raising my idle pressure to 50-60Mpa. I've also removed the dreaded regulator lope on a couple buddies trucks without lift pumps by that same trick.