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1991 Sunbird 3.1 starts easily, runs nicely for a few minutes, the dies. Restarting thereafter progressively produces worse results, harder starting, rougher running, less and less time till it cuts out. Thoughts?
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O2 sensor?'89 Firebird, 3500 Turbo, T56, 9-bolt/4.11
'86 Fiero, 3500, 4-speed -
I had the same problem on a 1991 Z-24. "Eventually"... i figured it out to be a bad injector, really low resistance. The ecm kept turning down the fuel to bring the to bring the A/F in line until it shut the engine off. Pop the upper intake and ohm out the individual injectors. Good luck.Comment
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could be either, really. or a failing coil/ICM.
unplug the O2 sensor, try and run it, you'll set a SES light, but if that's the problem, it won't reoccur.
the injectors used on the 2.8/3.1 failing is fairly common at this point, you may have to get the engine warm to see the injector(s) test badly, they could test well when cold.[CENTER][B]1995 Monte Carlo LS[/B] 3100, 4T60E...for now, future plans include [B]driving it until the wheels fall off![/B][IMG]http://i598.photobucket.com/albums/tt68/robertisaar/NewSig.png[/IMG]
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Unplugging the O2 sensor could also cause the engine to run better if the problem is a faulty injector.'89 Firebird, 3500 Turbo, T56, 9-bolt/4.11
'86 Fiero, 3500, 4-speedComment
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Wow, great info...thank you! I'll be back with updates when I have time to try these tests...thanks!Comment
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How do you 'ohm out' injectors? When you say upper intake your talking about the upper plenum right?Comment
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Found an article (series of articles) that explains testing the resistance across fuel injectors:
Also I haven't had time to get under the hood yet but I just started it and gave it gas before it was good and warm (last time I let it idle for awhile before giving it gas) and it was hesitating and smelled like a rich mix with unspent fuel coming out the exhaust. Does that help pinpoint O2 Sensor vs. Bad fuel injector?Comment
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Change that O2, get a Denso if you can. Have you tried some Sea Foam in the tank yet?95 Beretta 3100 with 3400 intakes and TCE TB
High flow cat and a Magnaflow muffler
Grand Prix trans with 3.33FDRComment
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Could be a plugged up cat, too. When they get hot, they can choke it out.Comment
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If it's rich all the time it could be the coolant temp sensor. I always say O2 because that seems to be what many overlook. Oh and if you have a cat converter on the car it's trash now.95 Beretta 3100 with 3400 intakes and TCE TB
High flow cat and a Magnaflow muffler
Grand Prix trans with 3.33FDRComment
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I think it is the coolant temp sensor! I think that was the one wire I couldn't figure out where to put back after I finished replacing the o ring on the oil distributer!!!!Last edited by hal.lyman; 05-19-2015, 11:23 PM.Comment
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First thing tomorrow I look here to make sure I did (didn't do?) that!Comment
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I had it plugged in....I did unplug the O2 Sensor and it ran much better! I would have let it run longer but it started smoking, I think it's where I sprayed some solvent and it just needs to burn off, all the same I don't feel like playing fire fighter today, but it looks like changing out the O2 Sensor might do the trick!Comment
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That's good, love an easy fix! Just remember to change the oil. That stuff has to have a good amount of gas in it.95 Beretta 3100 with 3400 intakes and TCE TB
High flow cat and a Magnaflow muffler
Grand Prix trans with 3.33FDRComment
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