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  1. #11
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    May 2018
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    Interesting, a knock like that would probably be heard by the engine knock sensors and kill power too.

    There has to be a better fix.


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    2021 Supra SA 400
    2018 Supra SA 400 (SOLD)
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  2. #12
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    Aug 2009
    Location
    Richfield, WI
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    Quote Originally Posted by larry_arizona View Post
    Interesting, a knock like that would probably be heard by the engine knock sensors and kill power too.

    There has to be a better fix.


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    No..no...“Knock sensors” detect detonation which is a specific frequency. It will detect this frequency for a period of time and then reduce timing until it stops. As a FYI a internal combustion engine is most efficient and produces the most power right on the edge of knocking/detonation.

    I wouldn’t call this a knock, I would call it a “tap”....metal tapping together...it’s something in the engine bay, NOT in the engine.

  3. #13
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    May 2018
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    Default Knocking noise at idle 2015 Mondo

    Quote Originally Posted by brad460 View Post
    No..no...“Knock sensors” detect detonation which is a specific frequency. It will detect this frequency for a period of time and then reduce timing until it stops. As a FYI a internal combustion engine is most efficient and produces the most power right on the edge of knocking/detonation.

    I wouldn’t call this a knock, I would call it a “tap”....metal tapping together...it’s something in the engine bay, NOT in the engine.
    I am saying knock sensors will hear false knock and pull timing.

    Exhaust rattle will get picked up as false knock. It can pick up noise anywhere in the engine bay. Knock sensors are microphones.

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    2021 Supra SA 400
    2018 Supra SA 400 (SOLD)
    Michigan

  4. #14
    Join Date
    Aug 2009
    Location
    Richfield, WI
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    390

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    Quote Originally Posted by larry_arizona View Post
    I am saying knock sensors will hear false knock and pull timing.

    Exhaust rattle will get picked up as false knock. It can pick up noise anywhere in the engine bay. Knock sensors are microphones.

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    You’re right in that a sensor is like a microphone...however an engine and drivetrain will make all sorts of noise...knock sensors are designed to detect detonation frequency- not random tapping or other knocking type noises... For example, if you were to tap on the engine with a screw driver it’s not going to start retarding timing..

  5. #15
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    May 2018
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    When you hook up hptuners you can see timing be pulled if the sensors hear anything that resembles knock.

    I will admit I am not familiar with Ford , But GM sensors pull timing with sources of false knock, including tapping with a screw driver.

    I wish the indmar ECM allowed use of HP tuners.


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    2021 Supra SA 400
    2018 Supra SA 400 (SOLD)
    Michigan

  6. #16
    Join Date
    May 2016
    Location
    Fargo, ND
    Posts
    127

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    My 16 mojo had a random knock that bothered me for the first season. Finally found out it was the plastic board that the ballast pumps are mounted too. Wedged a towel between it and the transom. Problem solved. Hope yours is an easy fix too.


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    2016 Mojo

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