The other night I went to start my car, cranked it a few times (carbed), and all of a sudden BOOM! It literally sounded like a gunshot went off. It woke up everyone in my apartment, and they really believed someone had been shot. :lol:At first I thought my car may have something in common with Uncle Buck’s, but when I started it I realized my new car had a nice growl that it did not possess the night before. I checked on it today- the muffler exploded out the sides. This wasn’t just a case of rust- it didn’t even look rusty- this bent nice clean steel really nicely. So it’s off to Mufflerman or somewhere else, because I’m not in the mood to do it myself. But WTF? :gotme:
BTW, the car is a '71 Pontiac with a 400, still runs fine.
Might want to figure out why it’s backfiring before you have mufflerman put a new muffler on. The muffer can’t cause a backfire like that so a new one isn’t going to fix the issue and the new one may get blown apart by the next backfire as well.
Thanks for the advice. Yeah, no sense in wasting money on a new one yet. So now that I know what caused it, what are the most common causes of backfiring? The car seems to run great, rebuilt within the last 2 years. I did have it backfire once before, during a cold start too. Both times the car had been sitting for a day, and it happened as soon as I started it.
maybe when you go to start it the gas is somehow not being burnt…maybe check the plugs and wires? Maybe the distributer isn’t powering right away and some gas is being passed threw the exhaust?
Just put straight pipes on it with turn downs, problem solved.
I’d say your bi-canusion double deflector valve was stuck open. Check the side with the vacuum hose on it and see if its pulling any vacuum. If it is then thats clearly not the problem. If its not that then you’re definitly looking at atleast 1 set of muffler bearings.
