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knocking/pinging??

Discussion in 'General Tech and Maintenance' started by highperboi, Jun 24, 2003.

  1. highperboi

    highperboi Senior Member

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    what makes knocking and pinging noises ???
     
  2. GSRCRXsi

    GSRCRXsi Super Moderator Moderator VIP

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    using gas with an octane rating thats too low for your motor
     
  3. highperboi

    highperboi Senior Member

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    yeah i know that but what makes the noise??? how does using lower octane make noise???
     
  4. xj0hnx

    xj0hnx I wanna be sedated VIP

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    Pre detonation cause the noise, meaning the air fuel mixure ignites before it should.
     
  5. dohcvtec_accord

    dohcvtec_accord WRX Sellout

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    :werd:

    The air/fuel mixture gets ignited before the piston reaches top dead center.
     
  6. no2psi

    no2psi Senior Member

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    highperboi,
    It sounds like you want a more technical explantion.
    Hot spots will allow the air/fuel mixture to pre-ignite. As the piston is being forced upward by the connecting rod, the pre-ignited explosion will try to force the piston downward. If the piston can't go up (due to premature explosion) and it can't go down (because of the upward mo-tion of the connecting rod), the piston will rattle from side to side. This is why timing is soooo important. The resulting shock wave causes an audible pinging sound. This is detonation. Enough pre-ignition generally results in detonation. These shocks waves are what cause ring lands to break etc...
    Hope this helps.
     
  7. riverfenix

    riverfenix Junior Member

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    i am getting the same tapping sound, i was wondering if that could be it, i have the apex s-afc and i was wondering if it is better to go alil leaner to stop the problem?
     
  8. highperboi

    highperboi Senior Member

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    kool i learned something new thanks
     
  9. no2psi

    no2psi Senior Member

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    riverfenix,
    If you even suspect your pinging or detonating, DO NOT! lean out your motor. Tapping could be a million things.
    Such as valve tap. Meaning your have too much play between cam and rocker arm. You should also get it on a dyno and watch the O2 reading. You might want to make you curve more rich if indeed it is pre-ignition.
     
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