fscm tune needed?

[dram1983361]

Hey peeps,

Awhile back I installed a flex fuel pump for same year model as my truck along with a flex fuel fscm from a 2011 suburban. Do I need to do anything special to any part of the tune? I'm getting some funky hesitation/bucking at w.o.t.

Truck is a 2008 GMC sierra 1500 2wd with 5.3/4l80e swap. Has not run right at w.o.t. since the 80e swap. I did the fuel pump at the same time. The 80e swap was done with the relay conversion harness (frost harness) that allows the use of the 60e tune to control it.

Truck cruises and idles fine so was thinking it was something funky with the new fscm/flex fuel pump. Cruise fuel pressure is around 43-45 psi and goes to 58ish at wot.

Tuner said he would see some fscm module error but no cell light on the dash lights up. And chalked up the bucking to something mechanical. Trans was new build from performabuilt and converter is an edge unit. Sometimes when I try wot, I'll lose 1st gear like a solenoid is stuck for a while and when all is normal, reverse is always delayed engament.

Any help is greatly appreciated.

[10_SS]

if you have 58psi at WOT and it's bucking and your still running normal gas (10% E85) then most likely the problem is the trans. Your logs would show you how it's running, logs probably wont do much for the trans diagnosis other than it seems to be running fine, must be the trans.

[dram1983361]

Alright thanks, its kinda hard to swallow that being it was a fresh build from performa-built =$$ wasted it seams