Quote:
Originally Posted by brianlay
Jwakil,
I agree your latest finding does point back toward the magnets/sensor. Would you say the odometer (20/31=.64) error correlates with the speedometer error (maxing out @ 60)? Driving at 100mph would read 64?
When I lost a single magnet several years ago the errors matched almost exactly.
I do agree that losing 4 magnets at the same time is really not plausible. It's easier to imagine a sensor failure mode that makes it less sensitive, but even that is a simply a theory.
When you do the sensor/magnet check, is it always the same ones that appear to be missing and are they evenly spaced, every 45 degrees?
Options that I can see-
-Bite the bullet and replace the sensor, although I'm usually not a fan of replacing parts without knowing if it's bad.
-Devise a method to test whether the magnets are really missing. I'm thinking that if you remove the sensor you might be able to use another magnet or a small compass? to detect them.
-Drain the transmission and remove the diff cover to inspect.
My vote would be the second option if you've got the time.
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Your second option sounds like an ingenious plan, but I'm not sure how much other metal is around that area which could confuse the reading. When I did the test with the ohmmeter, it seemed that the readings were pretty regular and evenly spaced (I did about 3 times) As mentioned before, what surprised me was that I was expecting brief blips but got readings that lasted a good 20+ degrees of wheel rotation approximately 90 degrees apart. And I was rotating the wheel fairly slowly. While I didn't write down exact degrees and readings, based on memory I got something like below:
0-60deg no read
60-90 ~70 ohm
90-150 no read
150-180 ~70 ohm
180-240 no read
240-270 ~70 ohm
270-330 no read
330-360 ~70 ohm
I have to mention that there was one time where I left it in a read location for a minute or two as I was doing something else and all of a sudden it stopped reading. As I started to rotate again to what I believed was the next magnet it started reading again. I don't know if this suggests something weird with the sensor or my voltmeter has such a slow response that I need to move the wheel super slow.