1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Hmm, changed the alternator and no more backfiring exhaust

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Old 06-14-05, 05:29 PM
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RotatingCheesehead

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Hmm, changed the alternator and no more backfiring exhaust

I changed the alternator on my 1979 RX-7 over the weekend because the old one basically died on me at a stop sign. Pretty embrassing thing to happen during Friday rush hour. I used to have a nice gurgly backfire with my RX - nothing obnoxious - for the first couple of miles after startup when coasting to a slower speed in 3rd or 4th gear, for example. Well, that backfire has been eliminated with the alternator change. Had to tighten up the belts a little too since they were too loose. I am really happy with the change. The car just seems to run a lot smoother.
Old 06-14-05, 05:37 PM
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Turbo widebody FB

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that is kinda strange, the only reason for that I can think of would be if you are still running a air pump that the belt being tightened was what eliminated it from the extra oxygen getting to your cats...
Old 06-14-05, 05:54 PM
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Or the new altinator now has a better cleaner charge providing more constant power to the coils and ignitors ....... wait its a 79 humm maybe never know.
Old 06-14-05, 07:14 PM
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Kinda makes sense. If you had a shitty alternator you probably had a really weak spark and it wasn't burning all the fuel. Now with a good alternator the spark is a lot better and it's burning all the fuel, so now there's no extra fuel to go into the exhaust.
Old 06-15-05, 01:58 PM
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Same thing happened in my 91. It wasn't backfiring more than usual, but it was running a bit rougher, which I thought was dirty fuel injectors or something. My alt belt started slipping, I tightned it (too much), snapped it, put a new one on and tightened it to proper spec, car runs much much better. I don't know exactly why, but weak spark could have been the issue.
Old 06-15-05, 02:01 PM
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Brap, Brap, Ole!

 
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for the record, how tight should the alt. belt be?
Old 06-15-05, 10:51 PM
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Hmmm, maybe getting the '72 RX2 alternator off my 7 and putting the original back on might cut down on my popping.
Old 06-16-05, 01:13 PM
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RotatingCheesehead

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I like the idea of the car running better, but I sure miss the previous "evil cackle" of my exhaust!
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