ive got a 92 firebird ive put an lt1 in and ive run in to a major problem with my fuel pump at idle it will stay running but once you put it in gear itll die. im not sure if its the pump or the relay but i replaced the relay and it still does it. i was messing with it and jumped across the terminals to give the pump direct 12 volts and it started working but then died again im using a 92 trans am pump so it should be putting out enough pressure. i really hope some of you more experienced people will have an idea cause its the only thing ive got to drive and i need it back soon
Thanks for any help
Steven

 

Which tranny are you running?

 

im still running the 700 r4 till i can aford a t56

 

That is probably the problem, the LT1 PCM needs to have a VSS signal from the VSS in the 4L60E or T56 for it to run properly, ask Firebat and ssean92 about the problems they were having. I think Firebat actually put a 4L60E tailshaft on a 700R4.

 

I removed 700R4 speedo gears. Heated and pounded a 1995 4L60E reluctor onto tailshaft of the 700R4. Swapped 700R4 VSS with 4L60E VSS.

I have heard you can buy a 4L60E vss in a kit that comes with the reluctor from the gm dealer.

 

wierd .. im running a 5 speed with no vss hooked up and mine works ok. maybee mad z turned it off for me when it was tuned. hmm.

 

mad z disabled the vss codes on my LT1/700R4 Obdi tune. Probably does the same thing for the T5. I'm surprised it runs ok with no vss still.

 

The vss doesnt do anything as far as the engines fuel mapping or timing contrary to belief. I was very concerned but was told by mad z it wont make any difference wether its hooked up or not.

 

it won't make any difference how it runs while cruising. wait till you pull up at a stoplight and try to keep the car running. mine would die or cough and sputter at every other light while I didn't have my VSS hooked up. Guess what, problem went away when I did hook it up. VSS input is used for the IAC control when slowing down.

 

Very weird.. it runs fine without it. i can hit stop and go traffic all day long. The last trip it saw before i garaged it for the winter was a 2 hr 40 min trip with no probs at all. You sure its used for the iac? Could be my tune is different too. donno ill have to ask madZ to see whats up.thx

 

The input signals are used for the idle, which is what keeps the car idled up a bit until you hit 0mph, then it goes to normal. There is a setting to take this out, so when you hit the clutch it drops all the way to 800rpm instead of hanging around 1200 or so until you come to a stop, which is supposed to keep the car from stalling out.

 

have u cked the fuel pressure? if it stays at 42 ish. that is what the lt1 needs. and if you are not using a l98 or lt1 pump it isnt geting the pressure it needs