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testing the knock sensor, OHM meter and continuity?

Old 10-10-2010, 10:55 AM
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testing the knock sensor, OHM meter and continuity?

Using an OHM Meter, does this seem like a credible way of seeing if the actual knock sensor is working or not?

I've never used an OHM meter, so I'm not sure the idea behind continuity and it working or not.

http://www.autozone.com/autozone/rep...00c15280060e05

It says if there IS continuity, then the sensor should be replaced. What does it mean if there is continuity?

I'm replacing the knock sensor wiring, but before I rip the intake manifold off my 3.0, I'd like to be sure the sensor is working while I'm down there...

Ben
Old 10-10-2010, 01:57 PM
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Best way to test is with an oscilloscope.
Old 10-10-2010, 02:10 PM
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How do you test it?
Old 10-10-2010, 02:23 PM
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Basically, connect the o-scope to the knock sensor and tap on the block. You should see a frequency wave on the scope.

It's a very simple test that should only take a couple minutes to complete.

Edit: I just tried testing a knock sensor from a MKIII Supra with a crappy old Wal-Mart special DVOM. I set it to the lowest voltage setting and touched the negative probe to the sensor's threads, and the positive probe to the signal connector. It showed a static voltage reading of around 20mV. When I tapped the sensor with a padlock I had laying around, that reading jumped to about 35mV, then settled back down to 20mV again. It's not the proper way, but if you don't have access to an oscilloscope I suppose it will work.

Oh, and one last thing, there should be no continuity between the ground and signal ends, obviously.

Last edited by shaeff; 10-13-2010 at 06:09 PM.
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