Backfiring Problem

Q: Backfiring Problem

I have a 1968 Firebird with a built 73 Pontiac 350 and an electric choke. The last two mornings on the first start it has backfired. I’m a pretty weak mechanic…as you can tell. What should I do.

A: I’d start with the choke. See if the is sticking and flooding. Also, check the timing. When was your last tune-up?

A: Your problem could still be in your choke. Is it backfiring through the carb or exhaust? If through the carb, most likely you have a lean situation that could be caused by your choke not closing fully. This would explain why it goes away when it warms up. If it is your exhaust, that’s another story and most likely would involve timing or a sticky exhaust valve.

The first thing I would do is check the position of the choke when cold. Before you start your car, remove the breather and open the throttle to allow the choke to close. If it doesn’t snap closed fully, there’s your problem. Check to see if you can close the choke all the way (there should be a slight opening about 1/8th to 1/4 inch when fully closed) by pressing it closed. If this is the case, buy a can of spray carb cleaner and hose the linkage. If the problems persist, you’ll probably have to grab a buddy (or mechanic) who know a little more about old cars and get him to help.

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