TimR wrote:
When I was growing up car backfires were common. As a kid I had friends
who could make it happen at will.

Now that the carburetor is long gone, most younger folk have never heard
one. Fuel injection eliminated this, I think; could be wrong.

I never understood exactly what happens. Usually a car would backfire
when under heavy load, and the gas suddenly let up. So my guess is the
carburetor had a full charge with nowhere to go. But what ignited it?

Or, possibly the lack of air made an overly rich mixture escape the
exhaust valves, and the explosion was in the manifold?

I think muffler backfire can be from too rich. Carb or intake backfire, too
lean. I had backfire in a datsun. I had to readjust airflow meter.

Greg