what exactly is a knock sensor??
04-23-2005, 11:05 AM
#1
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what exactly is a knock sensor?? i keep hearing about how some people have problems with the knock sensor and i have no idea what it is, i did a search but came up empty handed.
04-23-2005, 11:18 AM
#2
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it's basically a microphone...
It picks up vibrations in the engine, if the vibrations are outside of normal operating sounds it tells the PCM about it, and the PCM will pull timing amongst other things...
the Knock sensor exists to stop detonation as soon as it's detected
It picks up vibrations in the engine, if the vibrations are outside of normal operating sounds it tells the PCM about it, and the PCM will pull timing amongst other things...
the Knock sensor exists to stop detonation as soon as it's detected
04-24-2005, 02:03 PM
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As a device it is a piezoelectric crystal. It has 5 volt reference going to it. It eats up about 1/2 that voltage through it's own resistance. So it's about 2.5 volts hooked up.
When a knock occurs the voltage will change to above & below 2.5 volts. This is what the PCM sees as a knock, a varied voltage & amount of time voltage varies.
When a knock occurs the voltage will change to above & below 2.5 volts. This is what the PCM sees as a knock, a varied voltage & amount of time voltage varies.
