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Old 04-16-2005, 11:52 AM
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JimF JimF is offline
'94 S500: only 793 sold!
 
Join Date: Mar 2001
Location: San Diego, CA
Posts: 1,933
Do magnets really . .

Quote:
Originally Posted by Duke2.6
The crank position sensor, reference sensor - whatever it's variously called located at the left rear of the block that reacts to the flywheel segments is the one that is part of the ignition system.

Any permanent magnetic device that provides a voltage signal will slowly lose magnetic flux over its life and eventually will not generate enough voltage to operate the system, so even if the sensor doesn't fail in some way, it will eventually effectively "wear out" electrically.

Duke
wear out?? Not enough so that you would notice, per what I read. In ten years, it MIGHT lose 1%, not exactly a big loss.

There's three main ways that magnets can degrade:
1) Heat: but it must be taken to its Curie temperature.
2) Demagnetizing field: As strong counter productive field could cause it to lose strength.
3) Shock: The magnet is violently struck to cause it to lose some of it's magnetic properties.

There's lots of heat in the engine but it doesn't get to . . . 1900degs F. . the curie temperature.

The magnet on the fly wheel can have a very slight effect, MAYBE the 1% degradation number.

The 'shock' levels in a car come nowhere close to changing the properties a CPS sensor.

You are adamant about NOT replacing a high mileage O2 sensor, yet you think that a CPS should be replaced. In the eight years that I 'put-in' at my tech's shop, I have NEVER seen a bad CPS.

For Taboo: " . . car has original O2 sensor, check engine light comes on then goes off the past 2-3 months". Check the codes from the DM.
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