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Fouling the spark plugs????

Discussion in 'Technical Q&A' started by RAMMER, Feb 12, 2007.

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  1. RAMMER

    RAMMER Formula 3

    Feb 20, 2004
    1,187
    Miami
    Full Name:
    Rammer
    #1 RAMMER, Feb 12, 2007
    What exactly does it mean to foul the spark plugs? My cars' alternator failed and at the the same time it started running rough (mostly backfiring at high RPM). I was told by a respected mechanic that I had probably fouled the plugs. How does one fix this or does it have to go in the shop? What does this job entail? Thanks in advance.

    By the way....I rebuilt the alternator and the car is running strong but from time to time it still backfires after 5K RPMs.
     
  2. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    18,026
    USA
    #2 f355spider, Feb 12, 2007
    Means to simply replace the spark plugs.
     
  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,504
    30°30'40" N 97°35'41" W (Texas)
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    Steve Magnusson
    #3 Steve Magnusson, Feb 12, 2007
    Fouling is/are deposits on the spark plug electrodes that provide a conductive path between the two electrodes (so no spark occurs across the gap) -- see:

    http://www.ngksparkplugs.com/techinfo/spark_plugs/overviewp5.asp?nav=31000&country=US

    at the bottom of the page.

    Dave gave the usual best solution (but I wouldn't be too hopeful that replacing them will solve an RPM related problem -- but, for a few dollars, it's worth a shot and wouldn't hurt).
     
  4. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    18,026
    USA
    #4 f355spider, Feb 12, 2007
    Agreed, back when I owned by old 78 308GTS carb car, when I fouled plugs, it was usually at low rpm that I noticed it, and it would clear out, from 4500 rpm on up.

    But I would swap them out too, as it is a relatively inexpensive and simple procedure.
     
  5. Ken

    Ken F1 World Champ

    Oct 19, 2001
    16,078
    Arlington Heights IL
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    Kenneth
    #5 Ken, Feb 12, 2007
    Plugs foul from either gas or oil. Gas fouled you just change them although they can be cleaned if you have too much time on your hands. Oil fouled is the bad news because it means bad rings. Backfiring at high RPMs is not a usual symptom of fouling. As mentioned, fouling occurrs at low RPMs. You might have an electrical issue with missing/fouling at high RPMs.

    Ken
     

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