I have a 1983 Z28 Camaro with the crossfire injection. I swapped the 305 for a 350. Kept the manifold and swapped everything to the new motor. I put a 350 knock sensor, ESC, injectors, and computer chip. Since the 1984 Corvette had the same intake, i kept the crossfire. I figured it would basically be the motor from the vette. But i have run into one major problem. She fires up, and idles great. No problems. I got to give it a little gas and it sputters, backfires out of the throttle bodies and dies. The only way to give it more throttle is to be super gentle and ease it very slowly to higher RPM's. I am leaning towards a vacuum leak. The vacuum gauge i used was saying 8. I believe that is about half of what it should be. Any ideas suggestions? Im going insane over here!!!

 

What kind of chip did you get? Is it compatible with your old ecm? Are the injectors and fuel pressure the same as a vette?

Backfiring is typically related to timing so start there, wire by wire. Where did you set the base timing?

 

Does sound like a vacuum leak-on a vette forum i am
on,a member had that problem with an '82 vette-
after checking just about everything and subbing out
a few parts,the leaking hose was found...
Iv'e had a crossfire 350 in my car since 1994,modified
the injection and manifold and did a mild port job on
the heads-runs good!. Sounds like you have done all
the needed modifications for a 350 swap. Also really
helps if the stock fuel pump is swapped with one that
puts out at least 20 psi(TPI pump is often used) and
the fuel pressure bumped up to 14-15 psi(stock is
12-13 psi)

 

Hey thanks for the help! Yea im going to be going through all of my vacuum hoses today, They are 26 years old so i wouldnt doubt a leak.

 

Sound like your ign. timing is WAY off. My buddy has a 72' Ford f100 and it did the same thing. we re-adjusted the timing, and everything was fine.

 

I just replaced the distributor, so im thinking i may have it retarded about 20 degrees. im gonna pull and re-install it to make sure

 

ya it amost sounds like your 180 out

 

yep, check your ign. timing. thats prolly it.

 

I have the same setup that you do.Make sure to check into the CrossFire forum also. They might have some ideas