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How do knock sensors work / how to test?

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Old 07-10-2005, 09:58 PM
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Default How do knock sensors work / how to test?

Have knock sensors on the boat I am buying. In the sea trial, I never saw one move. That might be a good thing, if they are working. How can you / do you test them? These are Gafrig gages.
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Old 07-11-2005, 06:45 AM
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Default Re: How do knock sensors work / how to test?

Knock sensors are a piezo electric crystal signal generator. The vibration, at the correct frequency causes the crystal ti vibrate and generate a small electrical signal. this signal then shows on the scan tool or dash readout after being modified by the computers electronics. Test by tapping the bolck with a small hammer near the sensor.
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Old 07-11-2005, 05:21 PM
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Default Re: How do knock sensors work / how to test?

Thanks!
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