Hi I have a 90 camaro with a swapped 350 (about 350 up) tbi with headers. It will start backfiring violently through the air cleaner and idles supper bad and eventually dies. Will start again but not drivable. I replaced the fuel pump, fuel filter, plugs, wires, cap and rotor, coil, and even wrapped the headers in heat wrap. And only does it when motor heats up. Checked all electrical connections and vacuum leaks. I can't fix it! ANY help would be great.

 

Headers with heat wrap isn't normally a good idea. Most manufacters tend to void warranties for it due the wrap holding in extra heat, which can cause metal fratigue.

Sounds like a timing issue to me.

What change brought about this issue or did it just start to happen?

Can you hear it pinging?

 

symptoms before, and then what you did each step and symptoms afterward.

Did you do all of the work or can you confirm that it was actually performed?

If the symptom was the same, and you tossed all of those parts at it, it sure sounds like timing............but

you then go on to describe a situation in closed loop

a faulty O2 will cause rich and lean conditions and cause backfiring, erratic idle and stalling as described because the engine mgmt can't determine a good AFR, or, the ECM could be bad but less likely on the suspect list

 

I adjusted he spark plug wires on day and it started happening but that wasnt the problem. It jet started doing it one day. Ya I thought it was a timing issue too but how can I tell?

 

But before that it never had problems. Ran like a champ. I am out of ideas

 

Check your plug wires again. If it happened after they were moved or re-routed that makes me think a plug wire is on the wrong plug. If it is then it'd be firing out of order.

 

Well I would think so too but it runs fine till it warms up

 

Check the ignition module under the cap. When it gets hit it's probably breaking down. When the problem occurs, remove it and put it in your freezer for about 10 or 20 mins. Re-install on the warm engine and see if it's good. If it is it will only last a few mins before it screws up.

This is not the coil. It's a solid state part that's screwed to the distributor base with an electrical connector on it.

 

I replaced the module and it still doesn't work :-/ any other things?

 

It's been a while but I believe that there's a pickup coil around the shaft of the distributor at the top. It's what feeds the module. Meter it and see if it's failed. There's a specific procedure in the service manual for that

 

did you by any chance even read my last sentence in post #3 ?