injector data

[MTChevy]

Hey guys I have an interesting tuning issue im hoping you can shed some light on.

I have a 408 with a big cam, PRC heads, fast 102, fast cable throttle body, LS7 MAF, fic 42lb ls2 injectors. corvette regulator, 255lph in tank pump. its being controlled by a p01 system.

So the start of the story is I finished getting the car together, its a new build. 55 belair. The car started with some fast 46lb injectors. The car went to the dyno, everything seemed to be smooth except injector data. The tuner said there was no way they were 46lb injectors and ended up getting data in it for a flow rate of about 30lbs.

The car ran great on the dyno and pulled a 550RWHP number.

I get the car home and it has terrible driveability. Wants to die at idle, hard to take off in first gear etc. So i decided it needed more tuning. Well i had a different tuner look at it and we decided to get a good set of injectors since fast has terrible data and customer service. So i ended up getting a set of FIC 42lb ls2 drop ins with great data. The tuner looks at the tune and gets some stuff fixed. The idle is great, start up is great but there was issues. The car would not rev up. It would rev to 1500RPM then just surge, the scanner showed it going absolutely lean. It wont rev up past 1500 at all now and it doesnt hold that RPM, its almost like the fuel shuts off till it gets back to idle, surges back to 1500 and just continues that cycle.

So heres where it gets interesting. I plug in flow rates for about 29lb injectors and the thing will rev to the moon and everything is good. o2 shows it going rich when the throttle is pressed. At that point i started bringing flow rates up again and it slowly stops revving again and shows it going lean. Fuel pressure holds around 60, ive checked for restrictions in the fuel lines, installed new filter

What gives? the car runs good at a 29lb flow rate but you put it at the actual injector data and the thing is dead lean and wont rev? Sorry to be long and drawn out but this is driving me nuts. I am attaching the file that should have this thing running great, but wont let it rev. Thanks guys55chevy408 dtcedit MailOrderTuner remote LS7 maf.hpt

[5FDP]

For the hell of it, disable the abuse mode that is still factory set. Change the settings from 1,600rpm and 255mph to 8,000rpm and 0mph.

[kevin87turbot]

Put a fuel pressure gauge on it. You're most likely have a fuel delivery problem.

[MTChevy]

fuel pressure gauge has already been on it, never drops below 60, put a new filter on it, checked for line restrictions. No issues found

[Gyver-it]

I'm with 5FDP. I had that happen myself on an engine swap vehicle, that was the fix.

[MTChevy]

For the hell of it, disable the abuse mode that is still factory set. Change the settings from 1,600rpm and 255mph to 8,000rpm and 0mph.

I will give this a shot tomorrow and report back. Thanks!