I just put a 12:1 355 LT1 in my car....it has fully ported heads with 2.02/1.60 valves in it, they flowed like 245cfm.

Car has longtubes, 58mm TB, all the bolt ons....

the car acts like it has the plug wires out of order (popping etc.)

It has an Ed Wright chip in it and is running on 100 octane race fuel....has new fuel filter, A1000 fuel pump, 42# injectors.

Car doesn't idle very low, I have it set up around 1300 to keep it running.....

Never had this kind of problem.....out of Ideas etc.

I have checked....
Compression
firing order
injector pulse
fuel press.
Spark
Diagnostic codes
Vacuum leaks


Anyone have some kind of input?? Car is a 93'

What Fuel Pressure should I run??

Which Plugs/gap??

Thanks for any help...

 

The car had also been Dyno-Tuned by Ed Wright, they adjusted my IAC valve.......Could this be the problem?? How/Where should I set it??

 

The IAC as Im sure you know ill determine the idle. How many steps is it at, at idle? Have you cleaned it out? Is it in working order?

 

It won't Idle.....I have the set screw on my Throttle body set so it will stay running......between 1400 and 1600 RPM it sets around 80 or so.

it bounces around and doesn't stay constant...I changed back to delco plugs (1 step colder than stock) and went with a 40 gap instead of 35....it seemed to help, but it pops and backfires out the exhaust every once in a while and when you drive it....

Any Ideas??

I also noticed it isn't going into closed loop (even after reaching 190 degrees...)

What should the IAC read at 1,000 RPM's??

Thanks for the help!