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Fastbird

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  1. #1
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    Default Car misfire under load

    The car has started to misfire under load say above 2500 rpm. Car has new plugs gaped at .35 supercharged 8# crane cam ignition box. Wideband shows plenty of fuel

    i wonder If it’s the plug wires? Or hopefully not the opt. I’ll look for arch of the wires tonight. Is there a way to test the opt or coil anything els y’all I should check let me know.

    Problem stsrted out out of nowhere was running great then dog shit

    95 a4

  2. #2
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    Default

    Sounds like weak spark. It could be the opti but also the coil or wires. Def check for arching first as that is easy. You could try closing the gap to .022 or so and see if that helps. .035 seems pretty wide for 8 lbs of boost.

  3. #3
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    I just changed the plugs wires car won’t rev above 2500 rpm now ☠️. I’ll pull the plugs out tomorrow and see what they look like I know the car has been running rich, maybe I’ll get lucky and will need plugs or a new coil. Thanks for the feedback

  4. #4
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    Default

    Ok so I’m pretty sure it’s the opti... car would rev past 2500 today but still runs roughly. Misfire at idle. There is a screeching sound sounded like a belt slipping bad. I pulled off the belts for the accessories as well as well as the belt for the supercharger. Stilll makes the screeching sound. With that being said only thing it could be (only things turning) are the warred pump and opti.
    Fuel pressure looks good so I don’t think it’s a lack of fuel I fact the wide band is showing plenty of fuel a bit too much with the stupid fmu.

  5. #5
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    Default

    Sounds like it could be your opti. Always good to have a spare around to swap it out when issues arise. Hopefully, you can find a good one as I do not think AC Delco makes them anymore.

  6. #6
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    Default

    its almost always the opti

  7. #7
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    Default

    Quote Originally Posted by TheFknJm View Post
    There is a screeching sound sounded like a belt slipping bad. I pulled off the belts for the accessories as well as well as the belt for the supercharger. Stilll makes the screeching sound. With that being said only thing it could be (only things turning) are the warred pump and opti.
    .
    maybe the rotor is rubbing the cap of opti....or WP impeller is hitting the WP housing....although the later would not cause a misfire
    96 BBB 383/T56

  8. #8
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    Well I’ll find out soon for sure I got thr opti and water pump off last night wasn’t near as hard as I’ve seen ppl say. Heack the plugs where harder to change... then again I only got it all off haven’t had to put it on yet����♂️

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