Crank Sensor Polarity

[darkfa8]

Would the engine start if the polarity to the crank sensor was reversed?

Instead of C3I module Pins:

Ground G - BLK - Crank sensor pin B
10V+ H - GRN - Crank sensor pin A

to:

Ground G - BLK - Crank sensor pin A
10V+ H - GRN - Crank sensor pin B

?

Also, the GM diagram chart for the "Engine Cranks But Won't Run" troubleshooting guide has the Crank Sensor signal lead listed as a GRY/WHY, however, looking at my wiring, the wire coming out of Pin C of the Crank Sensor plug is a GRY/RED.

Additionally, the cam sensor power wire from pin A of the sensor connector is also GRY/RED.

Is the descrepency with the Crank Sensor wire color normal?

 

[GNVenom]

You can damage the sensor by reversing the polarity. The 86-89 wiring was oddly reversed on the crank sensor as compared to the 84-85 cars. Generally the gray/red stripe is a positive feed except for the crank sensor in the later years...it's the signal wire instead. The gray/red stripe is the positive feed for the cam sensor however. Crank sensor: A-green-positive, b-black-ground, C-gray/red-signal.
-John Spina
http://www.casperselectronics.com

 

[darkfa8]

thanks John...

i guess i can pull the crank sensor and bench test it by applying 12vdc to it properly and checking for pulse with a logic probe while moving a feeler gauge through the opening..

I did this same bench test on cam sensor caps to verify that they work.

 

[GNVenom]

If you bench-test the sensor, be sure to insert a pull-up resistor between the 12v and signal. The sensor sinks to ground during the interruptor window opening. The same applies to the cam sensor.
-John Spina
http://www.casperselectronics.com

 

[darkfa8]

what value/wattage rating resistor should I use?

 

[GNVenom]

10K resistor, 1/4 watt is all you'll need.
-John Spina
http://www.casperselectronics.com