i just checked this on my 944 (as it's being stubborn still) and:
1) the forwardmost sensor is MUCH higher from the flywheel than the rear one is. it's almost half an inch from the bottom of the sensor to the rim of the flywheel.
2) the rearmost sensor (close to the firewall), is close to .8mm / .032" but not exact. should it be nearly exact?
3) the only sensor that i really need to make sure is right where it's supposed to be is the rearmost one right? just want to double check this.
is there any impedance meansurement i can do to the sensors to make sure all are good (or defective for that matter). i wish i still hung on to my oscilloscopes

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thanks!
obin