Pinto Car Club of America

when i get on the gas hard, my car backfires. any ideas why?

Is engine warmed up ? is ecelerator pump working properly ? is ignition timming to far advanced ? are valves ok do compresion check.  Fred   :)

Yeah, I agree with Fred. Mine used to pop back thru the carb....ignition timing was the culprit

Joe

I had a burned #4 plug and it backfired on decel, not acceleration. It's fixed now, but it used to pop back thru the cat or sound like it was detonating in the cat sometimes. Getting straight piped soon since no emmissions laws in my area (yet :-\). I just took off the air pump and blocked the hole in the manifold with a 1/2" MIP (male iron pipe threads) from Home depot. car runs a lot better now. EGR is next to go!

Chuck :coolafro:

Since mine is a 72, I don't have a cat. I'm not running egr or charcoal purge canister. Then the next step is a 351w :)

It takes a lot more spark energy to run an engine under a load. Something as simple as a break in a plug wire or retarded timing will cause a backfire under load. My advice would be to start with a complete ignition tuneup including new wires and make sure you set your timing.

If its a 2.0L, check to see if the points are loose from the plate they mount to.