Ok have had my lt1 intake manifold off for month and a half now to install a nos pro shot fogger direct port kit...

Last night got everything installed and back together, (after fumbling with vacuum lines for an hour or so) and car starts revs to 2500 rpm, then dies instantly...

If I pedaled the gas to keep it above 2500 rpm it would stay alive, but die as soon as I let off.

I thought hmm bad maf, so i unplug it and try again, car revs to 3000 and just sits there, doesn't die though.

Anyone ever experienced this?

car is a 95 z28 383 stroker, with ported lt1 heads and portd lt1 manifold..ccxe236/242 bosch 36 lb injectors. any help is appreciated

 

TTT

 

what TB are u using? bbk 58mm? try cleaning your IAC.. my car did the same thing.. ended up the iac was stuck so i had to buy a new one.

 

that dotn sound like a MAF to me man...

 

Actually it is a holley 58mm, but the iac never came off the throttle body while it was off the car..

I will double check more things onight, I didn't have much time with it last night.

 

Well It was vacuum leaks....

retorqued manifold and pulled off nozzles and used some thread sealer on them and fixed problems.

 

Well this problem is not solved...

The intake gasket fell into the lifter valley during installation, and therefore caused the first round of problems. I have since replaced the manifold gaskets, and they are correct now.

I reassembled it all and the car runs ok, not great, but falls on its face every once in a while.

The BLMS are split huge like 140 - 117 at idle and will peg out both directions at part throttle when it stumbles.

Any ideas?

 

If im correct, people with aftermarket tb's on lt1's have to drill a holl for the IAC so that it can idle correctly. Someone chime in and correct me if im wrong

 

You are generally correct, and I got around this problem already. The car was already tuned and running great once, but i pull the manifold and put it back on and now it is whacked.


I did some datamaster logs tonight, the car idles ok, but it seems to have a misfire... Stupid thing is gonna be the death of me.

 

What's this about drilling holes in aftermarket TBs?

 

On the holley 58 mm t/b sometimes the iac passage needs to be enlarged and a tube inserted in it. This is only to be done if you have split blms at idle and no other place. It is usually necessary with smaller cams.

do a google search for it and look at LJ's site. great info there.

I think the adress is www.para.noid.org/~lj/ but im unsure

 

Anyone know how to check for a misfire on an individual cylinder? I think this may be my problem.