Connect your DMM on DCV between the crank sensor pink (lt green) and purple wires with the ignition on and make sure you have 12v. Do this with the sensor connected. Same set up but with the meter probes between the yellow wire and battery ground. Turn the crank pulley with a socket wrench or breaker bar in the proper engine rotation direction and observe the voltage.


George

 

Here is an excellent video on testing the crank sensor. Note he bumps the engine with the starter instead of hand turning the crank pulley. Also you have a 12v system not 5 volt.

George

 

Ooops, here is the video:

https://blazerforum.com/forum/2nd-ge...sensor-106127/


George

 

Finally made it back. The wife was in the hospital 2 more times, all is well now. I have to go have test on my heart and for me to go home and do nothing, which I can't do. I have checked and clean all the grounds under the hood, even took out the battery box and clean the grounds. Replace an engine to firewall ground. I watch the video on the crank sensor and got these readings. 12 v on pink wire, pink to purple 9.31. Yellow was 9.31.during test, bumping the starter the Yellow stayed at 2.30, it would go up about.10 but never got past 2.40-2.45. It never reached 12 v it is suppose to reach. Any idea?

 

Can you explain the yellow wire being 9.3V but then not going above 2.45v? Where is the black meter probe for these measurements?

George

 

Okay going back to 12/9/23 post. I test lt green and purple and got 12 v. Put ground of meter to batt ground and checked the Yellow wire it was 2.32. I bump the starter button looking for 12 v but nothing. I figured I may have passed it so I tried 3 more times still nothing. Everything was plugged in doing this test

 

You should be getting 12v on pink to purple, there is no green wire. If that's true then on this crank sensor you should have seen an alternating 9 or so volts and near ground as the crank was manually turned or bumped by the starter. Either the sensor is bad or its mounted wrong. Pull it and see if its hit by the reluctor wheel.

George