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spuggy spuggy is offline
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Join Date: Jul 2003
Location: Glorious Pac NW
Posts: 3,401
Originally Posted by Ronnie's.930 View Post
Does anyone know what the speed sensor "reads" (what is spinning withing the trans that the sensor is picking up) ???

It's a Hall Effect sensor. There's a few magnets in the box, as they move past the pickup (a simple coil, I'd presume), EMF is first induced as the magnet approaches and then collapses as it moves away, generating square wave pulses which are counted by the speedo head.

Speed/distance is then displayed based on the distance covered in a complete wheel/tire revolution - on the sizes of wheels/tires selected at the factory...
'77 S with '78 930 power and a few other things.
Old 01-31-2009, 03:21 PM
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