Heres a copy and paste from a girl having problems with a 3.1...

Ok fb people, I have a 91 camaro that wont start, It has new everything, and we have found out its electrical, I put a new PCM in it but its still not running, we got it running once then when we hooked the exhaust on it stopped running again, i am wondering if the PCM needs programed or maybe it needs a new chip because the fuel injector wont fire at all. HELP PLEASE!

Havent seen the car in person and I know this isnt much to go off of but with whats here what do you guys think? No one seems to be able to correctly troubleshoot it and are telling her to do a v8 swap. She says it has a new dizzy and the timing is good.

 

Are you saying it runs with the exhaust off but not with it on? If so take the exhaust off again and make sure it's not blocked anywhere, especially the catalytic converter if it still has one. If not that exactly how does it not run? Does it fire then die immediately? Not fire at all? Not much to go on yet. And suggesting a v8 swap as a solution is just plain lazy and very helpful.

 

Check the basics.

Fuel and spark, then go from there.

 

Tell her to test all of the fuel injectors.

 

Use a noid light to see if the injectors are pulsing, and then check the resistance. They should be at least 12ohm or more.

 

If the injectors turn out to be the problem then tell her to get re-manufactured injectors from SouthBay. I did and my Camaro is back on the road now after sitting for about 6 months.

 

Need to make sure that VATS (anti-theft) doesn't have an issue. Pull the codes from the ECM and check for a code 46. VATS also disables the fuel injection as well as the starter.

Yes, the car may crank, but that doesn't mean that there isn't an issue with the wire at ECM pin F10 (bottom of the yellow ECM connector, opposite the retaining clip) that provides the VATS signal to the ECM.