I did that before the timing. I did a complete overhaul on it but it started backfiring still ( it was backfiring before overhaul) so figured it was the coils so changed them out still same thing so I went deeper into the sensors still backfiring so did the timing and now no fire. I set it before unistalling the old chain so when installed the new one I didnt disconnect the battery which is stupid but someone told me that wouldn't matter. But I think it might have fried something.

 

You keep saying you "did the timing" on a car that you can not set the timing on. You just put it together, It may help me help you if I understood what you where doing to the car. You need to be more specific if you want help. "Complete Overhaul" Overhaul of what? the entire engine, fuel system, ignition system? You went "deeper into the sensors" What sensors? what procedure did you use with what equipment? With a car of this age there is just as much of a chance that wiring/connectors to the sensor are the problem. Have you checked for codes? Is the crank sensor picking up RPM as you try to start it?

Back fires can come from 2 sources, One is a ignition system the other is the fuel system. With out a scope it can be tuff you figure out where it is coming from. There is just as much chance it is coming from the ICM or the MAF sensor. Heck it can be caused by a plugged fuel filter.

Since you no longer have spark I would use a scan tool to see if the computer can see the engine rotation. If it does I would take the ICM to a chain parts store for testing. Call around many have the equipment to bench test ICM.

I am in no way saying this is what is wrong with your car but on my 1996 3800 the only running issue I ever had was a miss that grew into a back fire under load over about a week. Turn out it was the connector to the MAF sensor.

 

I am having the same problem with my 99 3800 camaro, in the spring I replaced the spark plugs plug wires coil packs and ICM and it ran fine for a couple months then one day my car overheated rapidly as I was trying to accelerate and it wouldn't go right away and then it the tires broke free. after that it had a miss. Then another day the car was really jerky as if it was I was stalling it out but it’s an automatic and it kept dying when we turned and i'm pretty sure I lost power steering as well, my fuel pump is pushing out 45lb of pressure so I know it's not that, we also did a battery reset on the computer that didn't seem to do much. I replaced the crankcase position sensor after that, but there is no spark in 1 and 4. and I found another forum that led me to the ecu, but I cant flash it with my tool because the car has to be running.

 

1 and 4 from the coil pack not the plugs

 

its the crankshaft sensor.