2055's bolted in, no cat, 3 inch flowmaster rest of the way back.

When i get it up like 4k-5500, it seems like its backfireing, but just a little, its weird. Like not full on boom out the TBI, but several noticable pops especiallly when i let off the gas. I've read that after headers i may be running lean. How do i fix this, if its the problem?

Also, one time when i hit it, i was shifting the auto manually, and it wouldnt break 3000 rpm's in 3rd gear. not sure why, it only happend the once. hasnt happened since. Anyone else have that problem?

-chuck

It sounds like you are a bit lean. I would check out the tech articles to make your regulator adjustable or go with an aftermarket unit. I would also bump the timing up a bit since you can get away with a little more when you add fuel. It may be a good time to look into prom tuning. Even something as simple as headers can throw these cars off.

yea, i was thinking timing too. Test and tune this friday at the race track, i'll get it dialed in there if i dont have to work.

How do i tell when i have the fuel preassure adjusted correctly if i do that free mod, i was thinking about it but wasnt sure how to tell when i have it adjusted correctly? I've got winaldl, should i use the readings my o2 sensor gives it? speaking of that, i really dont know what im looking for, which menu do i have to have up and what am i supposed to be watching for?

My next $200 is going to a prominator. sound good?

thanks,
-chuck

The prominator is the way to go. Check out your bml's to see if you are rich or not. 128 is the magic number. That is only the start of it though.

4000-5500 rpms? that is WOT and blms wont tell you much as in PE open loop. up FP a bit and try that or consider a vafpr to give you more gas at WOT..

yeah that happens to the best of us. increase fuel pressure

If it backfires when your coasting its caused by an exhaust leak.

my LO3 did that and i put the holley 670 TBI on it and it went away shes running lean

if you dont want to get the throttle body just drop in a set of 350 injectors for a TBI Truck

No it is not. Backfiring is bad timing or a lean condtion. An exhaust leak will just cause the car to run rough if it is close enough to the head. You may hear a popping sound but that is not a backfire.

I know there arent any major exhaust leaks, definetly none before the y pipe.

I'm really out of money now, minimum wage sucks and now with all this stupid akins stuff no one is buying fast food so im not getting many hours. So i cant get new injectors, 670, or a VAFPR.

I think i'll try the free mod tomorrow or thursday, test and tune is friday night and i think i'll set my timing then.

Ronny:
"that is WOT and blms wont tell you much as in PE open loop."

What is PE open loop? Is that when it just tells the computer it has 128 for the blm value? and so its not showing me the real blm value? sorry this is all new to me. i'll up preassure when i get that free mod done. Would bad filters cause this too?

-chuck

Popping when you let off the gas can also be caused by unburnt fuel exploding. My otherwise stock LT1 pops like crazy with a gutted cat and a cutout.

would a lower temp t-stat help that unburnt fuel thing? i still have the 195 in there for now. Is that a big deal, the unburnt fuel thing?

-chuck

whoops double

It's not a problem at all. I bet if you put a cat on you won't hear it at all. I personally think it sounds pretty cool though. A 160 stat might even make it slightly worse if that is what is going on.

do your headers have a.i.r on them because the o2 sensor adds 100 mv for it, and could throw off your a f ratio also.