I just rebuilt my camaro motor. My problem is it is backfiring out of the intake manifold. I bored it .30 over, cleaned the blocks and heads, reground the crank, put in forged pistons, and comp cam from summit. Got a new optispark dist. I had to put it together could that be part of the problem? Maybe I put it together wrong. It has fuel and spark, the ignition coil is good. My mechanic says the rocker arms and valves are installed correctly. The gas is a mix of old and new, with octane booster. I took off the emissions related things. The air pump, the egr pipe thing on the back of the intake manifold, and another pipe that ran around back of the manifold. (not the cylinder head cooler line) I read that it shouldnt cause trouble to do this though. There is a code that says the computer is bad, but my mechanic dont think it is that because it was working when the car originally died. (it locked up because it was low on oil, and a connecting rod spun off and scored the crank.) My mechanic doesnt know what is wrong, and says it could be a lot of money to find out. Has anyone else had this problem?

 

check your timing mine was out by 180 degrees and it was spitting fire out of the intake manifold chances are that that is what is wrong when you rebuilt it you must have lined up the timing marks but when you do it has th #1 cylinder at TDC on the exaust stroke not on the intake stroke pull you distributer out and turn it 180 degrees and see what happens.

 

My mechanic said he fixed the timing...

 

If it is not spark timing, which is pretty hard to mess up if your engine is an LT1, you could still have miswired plugs. Otherwise some intake valves are failing closing fully, camshaft could be out of phase, fuel mixture could be screwed up for a number of reasons. If the engine is running, it should be setting codes, a scan tool may give you a starting point.

 

check Your Spark Plug Wires i had backfiring when my wires were arcing