My car had been having problems with back fires, which I thought would be resolved by installing a new electronic ignition box. Well, I was wrong..... when I start the car it idles very rough and will turn off if I dont step on the throttle. When I step on the throttle popping noises start and fire starts shooting out from the exhaust! What could be the problem that is causing this?

 

sounds like an overly rich mixture. Any check engin codes? Its backfireing in the exhaust correct?

 

Havent checked for engine codes, but you are correct the backfires are coming from the exhaust.

 

Double check your firing order - I know, you did, but do it again, with a witness lol.

Make sure all plug boots are on firmly.

Check resistance on each plug wire one at a time - even brand new plug wires are bad (more often than you'd think).

I'm no expert, but every backfiring issue I've had was an electrical issue, not a fuel issue.

Good luck!

 

yeah I'll have to get one of my buddies to help me with the firing order lol. What is the normal resistance range for the plug wires?

 

Sorry - I didn't mean restistance, but couldn't think of the right term at the moment - I meant CONTINUITY. I don't know what normal resistance range should be - just make sure it's low (ie alot of continuity) so you know you're getting fire to the plugs. I've bought plenty of New plug wires that were broken inside, or had shorts.