I have a 1993 Dodge D150, V6 3.9L. There truck is cranking over but not starting. So far I have replaced the crankshaft position sensor (which I was certain was the issue), the ignition pick up/hall effect sensor, the cap and rotor.

With a test light I am able to see that when the key is first turned to the on position there is power being fed to the ignition coil. After a second the ASD relay opens the contacts and power is cut off from the ignition coil. As far as I know that is functioning correctly. When I go to crank the engine the power to the ignition coil is on for a half a second and then cuts off completely. Even if I physically close the ASD relay so the contacts are closed their is still no spark when cranking.

I reset the computer and cranked it again. The check engine light indicated Code 11. No Crank reference signal at PCM . What am I missing here? To me it still seems like the Crankshaft position sensor is not working. Anybody have any ideas I am pulling my hair out trying to diagnose this thing.

 

did you use a mopar crank position sensor? aftermarket ones seem to be junk

 

The sensor I bought was from NAPA/Echlin.

 

Would a faulty PCM throw this code?

 

did you compare it to the stock sensor when you replaced it? when i had mine out i found a noticeable difference in size between an aftermarket one and stock and engine ran like **** with the aftermarket one which i would assume was due to the size difference.

 

Everything looked kosher with the new sensor. Same size, orientation, wires, etc. I don't have it out of the truck right now to be 100% certain however.

 

So I went to test the output signal from the crank sensor and instead of getting a switching signal from 0-5 volts I was getting a steady ~2.5V signal when cranking the engine by hand. Bad sensor?

 

Pulled the crank sensor out and did some testing again. The power feed is still showing 5v. The ground is still good. But now the signal output connection is showing 9v even if I disconnect the crank sensor and test the connector going to the pcm directly. Does that make any sense? Shouldn't that wire be 0 volts from the PCM?

 

Yes, that wire should have no voltage when disconnected. If it does, then you have a PCM problem. (or, a wiring problem.....)

 

Thank you that helps me immensely in diagnosing the issue. I am thinking I should buy a replacement PCM. But I heard that those failing are rare and if they do fail it is a result of something else going wrong. Do you have any tips on where to start?