Why is one spark plug black

Posted by dsmfreak95, Dec 18, 2009
Newbie Forum - Beginner/newbie/general DSM modification questions. First mods, how to run 10's when you haven't run 12's yet, any tech question that doesn't fit in another tech forum.

  1. dsmfreak95

    dsmfreak95 Proven Member

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    jackson, Tennessee
    I was checking my spark plugs the other day and I noticed that the 3rd one( from left to right) was kind of black, and the other three looked good. I have a dynatek coil on plug set. I was wondering what's going on. I've also been haveing a problem with the car sputtering. Could the third coil be going bad or what?? Ive really only had the one the car about 8-9 months. Any help would be great. Thanks
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  2. Kickerbeast

    Kickerbeast Proven Member

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    Post a pic if you can. It could mean different things. Could be carbon from that cylinder running too rich, or it could be oil from leaking valve seals. A pic would help greatly. Either way, whatever is causing this is likely causing your sputtering problem
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  3. 95blackGsTurbo

    95blackGsTurbo DSM Wiseman

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    Since your car is sputtering, I would suggest checking compression on that cylinder, ohm out the injector and check the coil packs resistance as well. Injectors should be between 2-3ohms. If you let me know what kind of coils you are have I can get you the specs on them as well. Definitely sounds like that cylinder is misfiring for whatever reason.
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  4. dsmfreak95

    dsmfreak95 Proven Member

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    jackson, Tennessee
    I'll try and post one this afternoon, I don't think it's running rich though because the plug didn't smell like gas.
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  5. Kickerbeast

    Kickerbeast Proven Member

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    doesn't have to smell like gas. If it is just a little rich it will get carbon build up. If it was rich enought to smell like gas, then it would like be completely fouled and wouldn't fire at all. Then you would have a constant miss.
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  6. crimsondragon

    crimsondragon Proven Member

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    Was that plug properly gapped?
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  7. SBR Joe

    SBR Joe Proven Member

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    X2. i had a headgasket pushing an ever so slight amount of water into one cylinder and the plug was black as night. Dry as a bone, just enough to blow the spark out. Could also be a sticky injector, but start with a compression test. If that cyl is lower than the other ones, you know where the problems lying then.
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  8. dsmfreak95

    dsmfreak95 Proven Member

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    jackson, Tennessee
    Yea because that's the reason I took it out in the first place. I made sure they were all tapped at .028. If I were to change the spark plug out would it run better for a little while?
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  9. Kickerbeast

    Kickerbeast Proven Member

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    Depends on what exactly is causing the issue with the plug.
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