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knock sensor failure? symptoms?

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Old 12-08-2006 | 09:22 PM
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^^^ VERY IMPORTANT

this style knock sensor has a sensitivity related to torque.
Old 12-08-2006 | 09:26 PM
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9NM '86, '87
20NM for '88+
Old 12-08-2006 | 09:53 PM
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I saw that too. I'm going torque down the new sensor and then check the klr harness pins again. Should the battery be connected or does it matter?
Old 12-09-2006 | 12:02 PM
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Originally Posted by por951turbo

Can someone measure their spare sensor and see what readings they get with the meter?
Measured a spare and it is 305-307 k-Ohms.
Old 12-09-2006 | 12:08 PM
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Thanks Jim. So you just put the positive and negative lead on the sensors terminals then? What ohm setting on the meter did you use? Only way I can get a reading on either sensor is if I'm using the mega setting and then it comes out to 4.8 mega ohms. I hate to think that the new sensor is bad too.
Old 12-09-2006 | 12:09 PM
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I cannot get a K reading at all on the new or old sensor.
Old 12-09-2006 | 12:13 PM
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Originally Posted by por951turbo
I saw that too. I'm going torque down the new sensor and then check the klr harness pins again. Should the battery be connected or does it matter?

The torque wont affect the resistance measured across the sensor, that will just affect its sensitivity to detecting knock when the engine is running (if the mating surface is not in good/solid contact with the block, the knock frequency/vibration may not be transmitted from the block to the sensor).

If you are just measuring the resistance across the sensor and across the KLR/Knock sensor wiring, dont have the ignition on either. But it shouldnt matter if the battery is connected or not.

May want to make sure that your multimeter is functioning or set properly. Check the resistance across a short length of wire or piece of metal. It should show very little resistance (probably less than an ohm), or touch the two multimeter probes together - again it should read nearly zero resistance.

If you check the knock sensor directly off the pins, and get a 280-330 kOhm reading, but get infinite resistance when checking the KLR wiring harness pins with the sensor connected, you have a break in a wire. If you get significantly less resistance through the wiring harness than the sensor alone, then you have a short and the wires are touching each other somewhere along the way.
Old 12-09-2006 | 12:14 PM
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I found one of my spares and I couldn't get a result either, it was measuring infinite resistance. I have been running a knock counter for a few weeks and the sensor was definitely responding before I replaced it. I replaced it with a brand new one with no change in behaviour. I also thought I had wiring issues so I bought the Lindsey crank sensor and knock sensor harnesses. In the end I changed the entire engine harness and didn't use the Lindsey ones.
Anyone want to buy Lindsey harnesses?
Old 12-09-2006 | 12:20 PM
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Originally Posted by por951turbo
Thanks Jim. So you just put the positive and negative lead on the sensors terminals then? What ohm setting on the meter did you use? Only way I can get a reading on either sensor is if I'm using the mega setting and then it comes out to 4.8 mega ohms. I hate to think that the new sensor is bad too.

Yes, I just placed one probe on one pin, and the other probe on the other pin.

I have a Craftsman Professional series multimeter, and it has just one resistance setting. It automatically determines what ohm range to display. It does require selecting a range when measuring Current/Amps (4mA, 400mA, or 20A).
Old 12-09-2006 | 12:21 PM
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I found my other spare, and same result, infinite resistance at lead on my digital multimeter.
Old 12-09-2006 | 12:23 PM
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So does that mean I have another bad sensor then? This is getting frustrating? Samluke, can you getting a reading if you turn the resistance up?

Jim, I've got to meters that I'm using. Touching the lead ends toghether gives me .001k of resistance at the most, it ends up being on zero.
Old 12-09-2006 | 12:25 PM
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I'm lost then. I can't imagine that I've got two new sensors bad, but I guess it's possable.
Old 12-09-2006 | 12:32 PM
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Sam,
How much for the knock sensor harness from Lindsey?
Old 12-09-2006 | 04:24 PM
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I paid $45 for the knock harness and $130 for the sensor harness, shipping was $9.

Por951turbo, I don't know where the the 300k ohms comes from. I can't get that reading from my spares with my meter. I also have DME and KLR manuals and neither give a sensor check value, so I don't know what gives either.
Old 12-09-2006 | 05:58 PM
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Ok, well believe it or not I had two brand new bad sensors. I went and got Shane's spare today and tested it and I'm now seeing the 330k at the sensor and harness. I dumb founded by this. Time to go put everything back together and feel the power my car has been missing for over a year now.


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