I just installed a new 350 GM crate motor in my car and am having some problems with the idle and check engine light coming on. I even put in a new computer and a million other parts in the car. The only thing I did not replace is the prom chip. GM does not make the chip for this car anymore. Hypertech makes a chip for the car but for only a 305 engine. I can't find any companies who can burn me a chip for this car with a 350. What do I do? Any suggestions would help a lot. Can the 305 chip from hypertech work anyway and still do the job? Or do I need to get a chip for a 350? The car is changing the idle from 500 to 2000 for about 2 min. every time you start it, doesn't matter if it's cold or warm. Then when I drive down the freeway the check engine light comes on and the idle will pick up and the car runs better with the light on. The car is running way to lean and keeps over heating too. Can anyone help?!!!!!!!!!!!!

 

Ok, what I know about CFI barely overflows a thimble but you do recall that 82 and 84 Corvettes were Crossfire injected 350's?

I'd suggest using Vette injectors and chip to see if your issues are cured or at least diminish.

 

hmm...

hvae the throttle bodies been rebulit or anything ever??

i know mine werent working the best... and other things were wrong so i was forced to go to a carb... (carb swap was cheaper than getting 2 rebuilt throttle bodies for a crossfire setup )

when i took off the top plate of the intake to take the intake off, it had quite a bit of gas just sittin in the intake

also had dirty injectors or something even after fuel injection cleaner went through...

 

The car has never had the throttle boddies rebuilt to my knowledge. I purchased the car from the original owner, the car has 75,000 original miles. The car sat for about 6 years or so, that's why I had to replace the motor. It's in the shop right now with a guy who owned an 82 cross fire. He is telling me the injection system is fine. He keeps coming back to the prom chip as the problem. I found out today after he ran some numbers on the chip that the chip is not made for an 83, it's made for a later model car. Anyway, how is your car with a carb? Everyone who knows about cross fire says it's crap and slows your car down a lot. My 84 z28 with a 305 HO carb would still smoke my crossfire with a new 350, something is wrong with this picture. Was it hard to convert to carb, how is the gas mileage? I am getting around 21 mpg right now with 3/4 freeway and the rest city traffic.

 

well neither one really ran right... it was a used carb we had laying around... i really didnt notice much of a difference after swapping to carb... all it did was get rid of the uberrichness that would kill my car at idle in gear... it also got rid of the detonation that was cause by the cfi...

i got like 18 mpg half city half highway... and i have a heavy foot

if you do decide to go to carb sooner or later, and dont want to save the cfi stuff, pm me and i may buy it from you... i plan on restoring my car some day... already had one cracked cfi intake.. good thing i had a spare back when i used it... cant hurt to have another spare intake..

 

I got a call from my mechanic today and he said the same thing you suggested to me. I am getting fuel injectors for a 84 vette and prom chip for a 84 vette also. I am told this will solve my problems. Thanks for the info!

 

Thanks for all of the info and help! For now I am going to stick with the cross-fire and put new injectors in it and try a prom chip for a 84 vette which came with cross-fire and had a 350 in it. I will keep you in mind if I decided to change to carb though.