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Thread: MSD knock sensor

  1. #1
    Animal Magnatism
    For those who have used one (part# 8964) how sensitive was it?? I have just bought one and it only shows knock when I can actually hear it anyway!! I have the sensitivity up full. Does placement in the block have much to do with the sensitivity?? The instructions say to run your motor at 2500 rpm and adjust the sensitivity until the first green led comes on. I dont think I get anywhere near that happening. Could I have a faulty sensor??

  2. #2
    Maybe it works backwards sense your down under. lol
    On mine when the engine was warming, it would pick up the pistons slapping. it would be in the amber and after it warmed it would stay in the green.
    Sounds like it's working to me. Lightly tap on the block with a wrench or hammer and light should flicker. I had a roller lifter go bad and that sucker picked that up at idle.

  3. #3
    Animal Magnatism
    Backwards lol. The unit I have doesn't work anywhere near as good as what your describing. I think my problem may be with the grounding. I'm currently grounding it through the ciggarette lighter socket. I would think the voltages coming from the sensor are pretty small and so would need to ground close (electrically) to the sensor itself. Will try directly to the block, near the sensor.

  4. #4
    Animal Magnatism
    Changed the grounding and that made no difference. Tried another sensor and that made no difference. Perhaps it is the placement of the sensor?? (which I cant really change). Anyway, being an electronics tech, I did as all techs would do and pulled it apart, probed around with my CRO, changed a few values here and there until I found an acceptable increase in sensitivity (by tapping the sensor on the edge of my coffee cup). Works as expected now.

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