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6.2 Ilmore backfiring

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  • 6.2 Ilmore backfiring

    I have a 2014 X25 with the 6.2. Last week, the boat started backfiring pretty substantially under load. I thought it was just bad gas so I put some octane booster in. It ran fine for a little while but the backfires are still coming. Not as much as before though. Engine seems to run perfectly fine, but the backfires are concerning. They happen sporadically. Might be once in 30 minutes, might be once in five. No consistency to when, and sometimes under load and sometimes after backing off. Could this be an ECM issue possibly? Plugs? Injectors? The plugs are relatively new, but have never done anything to the injectors. Thanks for any advice in advance.

  • #2
    Best bet is damaged electrode on spark plug. Pull all the plugs and inspect. I would change them all out. If not that, In Diacomm have your shop do an injector kill test. RPM's should drop as you kill each cylinder one at a time.


    • #3
      The back firing is un-burned fuel that is igniting in the exhaust. It sounds like it is happening under load. It is not an ECM issue. To start with the easiest checks, change your spark plugs and look for one that is either damaged or severely contaminated. If you find one, this was most likely the cause. If the plugs all look good then you probably have a fuel or air related issue.

      Again, start with the easiest for air and clean the MAF / throttle body. Only use a MAF specific cleaner!

      You could have a fuel injector that is getting stuck open or closed. Stuck open would lead to too much fuel all the time. Check your oil dipstick to see if it smells like a lot of gasoline. Stuck closed or low fuel pressure would have other symptoms besides the backfire, like missing under load.