Posted this in general technical help but got no reponse Hello all, In March bottomed out and needed new belly pan, some straightening and broke transmission fluid cover. Get the car back in July and now it back fires. NEVER did in the six years I owned it. I am confused and concerned about why now?!?! Crack in exhaust system? Something jostled up in the air intake?? From sitting for months?? (Did the Italian tune-up, and it's a little better) Need a real tune up? (I get one every year in October) Timing knocked off?? (No more points, went electronic) Doesn't do it much when at idle, mostly at the "bottom" or "start" of a gear when pulling. Sometimes it's a high pitch "ting" and sometimes a loud, deeper "pop". No loss of power. (Can still "chirp" third gear!!!) Any help will be greatly appreciated. Thanking all of you in advance, Yours, Tom
This may or may not be relevant to your situation, but a few weeks ago I was out at Lime Rock on the track, and the car started backfiring on me like crazy. The car had never done it before. I had converted to an Electromotive electronic ignition previously, and it turned out that the timing ring on the crank had come loose and moved, throwing off the timing. I didn't realize it until the car finally died when the ring cam completely out from under the sensor. So, I think the first thing I'd look at on your car is the ignition system, particularly the timing. It's possible that something got moved or dislodged when you had that hit. Another thought -- when I had my Mondial QV, it started backfiring like crazy. Turned out that the baffles in the exhaust had rotted out, and after hitting a big pot hole, the baffles collapsed and the car started backfiring. Put on a new muffler and the car stopped backfiring and went back to normal.
Thank you for your help. It appears to happen only when the engine is hot and not at all when it is cold.
Tom, Has the air injection system been removed in your car? If the air pump was removed or disconnected, but the air injectors were not removed, that could be the source of the leak in the exhaust as well as the whistling/chirping noise you are getting. The old air injectors must be removed and properly plugged up. Just another thought there. Also, if the car was sitting for many months unused, it's possible the gas went bad or the carbs are gummed up. Wouldn't hurt to get rid of the old gas, if you haven't already, and put in some fresh stuff (good quality 93 octane), remove the air filter and shoot some carb cleaner in there while the engine is running to de-gum things. Just a couple of more random thoughts here. Steve
