crank sensor signal wire problem

[hoffman5565]

Ok so for the last couple weeks i have been chasing down a no start issue with a 97 c1500 with a 4.3. I have traced the problem to the crank sensor signal wire. Instead of the 5v and 0v on off signal it should be sending im getting a constant 8-8.5v signal. I have changed the sensor with 2 new ones and changed the pigtail with a new one and i still have the same problem. Does anyone know if the pcm would cause this?

[Von]

Ok so for the last couple weeks i have been chasing down a no start issue with a 97 c1500 with a 4.3. I have traced the problem to the crank sensor signal wire. Instead of the 5v and 0v on off signal it should be sending im getting a constant 8-8.5v signal. I have changed the sensor with 2 new ones and changed the pigtail with a new one and i still have the same problem. Does anyone know if the pcm would cause this?

IIRC, the middle ground wire is internally ground via the PCM. If for some reason the gnd was ever shorted with the 12v line, it could fry the PCM.

I'm not sure but, if the gnd is shot, it won't be able to drop the voltage to 0v when the crank notches triggers the sensor.

Make sure the 12v feed isn't shorting to the gnd by melting on exhaust or animals chewing wires. If so, any new PCM might fry as well.