Hey all,
I just replace the ignition module on my 83 camaro (305 carb) due to no spark, and there is still no spark, I'm getting juice to the distributor and I did a resistance test on my coil and it's good, when I got to turn it over it turns over fine, but doesn't run, then if I turn the key directly to the off position after turning it over it backfires through the carb, no fire, but somtimes gas and sometimes exhaust, I don't think it's timing but it could be, I have my firing order correct, and have turned the dirstributor as turning over and no spark. SUPER CONFUSED! Any help would be strongly appreciated.

Thanks, DacMan

 

have u tried taking a spark plug wire off and stuck a screwdriver in it and held it close to a ground like the exhaust manifold while someone turns the motor over. if u have spark then u should see it. did u take the distributor out?

 

Check the spark as craby said. Also bring the timing mark up to TDC on the engine, (on compression stroke) pull the cap off and check to see if it's pointing at #1 cyl.

 

A backfire out of the carburetor (intake) happens when there is fire in a cylinder and an intake valve is open at the wrong time.
Or if the valve is open at the right time but ignition is firing at the wrong time.
Some possibilities are:
Ignition timing is off (either the distributor is swung or plug wires are crossed)
Plug wires are bad/misfiring
Distributor cap is carbon tracked causing cross-firing
Valves are out of adjustment
Valves are stuck or burned
Broken valve spring

 

I have been testing my spark, and that's why it back fires when the key is turnede in the off postion, I have the #1 cylinder spark plug sitting on my exhaust manifold so that I can see when it sparks, and it only sparks when the key is quickly turned from all the way over (the starting position) to the off position, I don't think it's a burnt valve or broken spring becuase I just rebuilt the heads. And I just replaced the plugs and plug wires. And the cap "points" are clean I cleaned them up with some 600 grip. Somone told me it was the pickup. Does that sound right?

Thanks, DacMan

 

now check to see if your getting power to the coil with the ignition switch in the on position.

 

I am getting sufficiant power at the coil, and when cranking. I did a Chiltons troubleshooting "tree" for no spark, and it led me to testing the tach spade. The book said that if I had 10 volts or less then my ignition module was bad. lol. I just replaced it. Now I really don't know what to do.

 

Pop the valve covers, start the car and watch your lifters. Make SURE they're moving freely and aren't stuck open or closed.

 

Sure you have the distributor in right? you took it out when you did the heads

 

bring it up to tdc and take the distributor cap off and see were the rotor is. should be at number one plug wire outlet, after that and while the caps off turn it over to make sure the rotor is turning. if u took the dist. out then it could be in 180 degrees off.