89 Bronco running rich - FSB Forums
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post #1 of 4 (permalink) Old 10-04-2008, 12:22 PM Thread Starter
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Location: Dallas,GA
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Bronco Info: 1989 Bronco 351w C6 32's
Angry 89 Bronco running rich

Hi i have an 89 bronco with a 351 and a c6. it is sped density and runs great while driving. it just idles rough and blows black smoke out when it shifts gears or at initial startup. every time you start it 2 clouds of black smoke appear out the sides, and all the time it runs it smells very very rich. lately it gets crap for gas mileage used to get 14 now gets 7. i ran 93 octane in it and no difference.
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post #2 of 4 (permalink) Old 10-04-2008, 12:30 PM
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Bronco Info: 89 XLT, 5.8, C-6, BW1356, factory LSDs, 33s
If you haven't checked for codes do it now. There are many threads on how to do this. Faulty O2 sensor, bad EGR are a couple of things that could be wrong. But def. check the codes first.
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post #3 of 4 (permalink) Old 10-04-2008, 12:44 PM
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Bronco Info: 1995 Eddie Bauer 357w, E303 cam on S/D, 3 inch exhaust with flowmaster 40, Flex-A-Lite
Originally Posted by Bilzhorse View Post
If you haven't checked for codes do it now. There are many threads on how to do this. Faulty O2 sensor, bad EGR are a couple of things that could be wrong. But def. check the codes first.
Or ECT (engine coolant temp) sensor........... But yes pull codes first.
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post #4 of 4 (permalink) Old 10-04-2008, 01:07 PM
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Or BAP sensor. Or bad PCM. Or a bad fuel pressure regulator. I could go on and on. Also, you are wasting your lute if you are running anything over 87 octane and there is no ping. The function of octane is to slow down the burn of the gas (thus losing power if you do not need it). Ping is gasoline exploding in the combustion chamber prematurily. So if you do not have that, you will be good ta go with 87.

The problem with the older systems is that the ECT, BAP, FPR, and a few other problems may not trip a code (including the PCM AND at times the 02s). So try the codes first and then you will have to start with a wiring diagram and a break out box.


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