[Blown69RS]

I have the Covan's Classic instrument panel with the Autometer Gauges. Currently having some difficulty with the calibration/operation of the Autometer Speedometer.

I purchased the two wire speed sensor directly from Covan's. It has 2 wires coming from it, 1 black and 1 white. These 2 connect to the 2 wires leading to the dash harness. Those 2 are purple and yellow (twisted pair, purple is signal and yellow is ground).

My question is which wire from the sensor is "signal" and which one is "ground"?? I assumed black was ground, but my speedometer isn't working. It'd be easy to switch them around down on the transmission, but I thought I'd check here first....

Any one else with the same setup?,, could you let me know which wire is which off the sensor on the tranny???

thanks.

 

[greenham]

I can't say I know for sure, as my sender from Autometer via Covans had 3 wires on it. The black was ground, and the white was the signal. I had a red on e that went to the ign side for power.

 

[ZZ_430]

That's right. I thought to 2-wire was Ford only.

 

[tawodi]

86 Z28 350TPI. I was sent a 2 wire sending unit with mine. After all was installed the car would shutdown around 35 miles per hour. What we found was that the unit was telling the ECM I was going 130 and the ECM was shutting off the fuel pump. Replaced with the 3 wire and now works great. I was told it has something to do with square wave signals vs something else which I still don't understand. Replaced chip and changed speedo gear in tranny to a gear with more teeth and now I know from experience my car will run 150 without the ECM shutting it down.