I have just performed the Crank Sensor test as described here:
Part 1 -How to Test the Crank Sensor (GM 4.3L, 5.0L, 5.7L)

When I measure the voltage on the signal wire I have a constant 9 volt on it. It doesn't change when I crank it with a wrench.

I guess the sensor is bad in some way but I thought that a broken sensor wouldn't give any signal at all.

Any thoughts?

Thanks


Jan

 

Read through this thread of mine. The last post may interest you the most. https://blazerforum.com/forum/showth...144#post411144

 

Thanks for the reply, but on your last post. My cover is the original to the engine. However the crank sensor isn't GM original.

I will try to hook it up to 12V today and do the bolt test you did.


Thanks


Jan

 

Post back results.

 

New cranksensor mounted. It started on first crank

 

Awesome. Feels great doesn't it. Were you able to confirm the sensor was bad before you replaced it?

 

Yes it was a great feeling but it didn't last long. It died again after a few miles...

I have to check it again. I think it is something else because it did fire a couple of times when cranking. I will start looking in to it tomorrow.

About the sensor. When I had it out I hooked it p to 12V and the signal wire will give 9V all the time, so there is probably some short in it.

Jan

 

Sorry to here that. When you had the new sensor hooked up to 12 volts and your meter hooked up to the same ground and the signal wire you didn't get the meter to change from voltage to no voltage when you moved a large bolt very close to then away again from the CPS? Bolt has to be Steel. If this was hooked up independent of any wiring on the car and voltage to no voltage changes were not there you have a bad sensor. If it was a working sensor and is junk now, I would check all wires for shorts to voltage, to ground and to each other with the sensor and VCM unplugged. The pink wire may be grounded when its relay is not energized so I believe you need to find and remove it to properly test this for shorts.

 

Well I tried to start it just now and it did start. I could drive it up on my parking space from the street and then it died again.

There must be some damage to some cable. When I tested the old sensor I pierced the signal cable to be able to read the voltage. Might have damaged the cable then.

I'll check some more later.


Thanks

Jan

 

The crankshaft position sensor is continuously monitored by the PCM. If there's a problem with it, or the wiring to and from the PCM, a DTC will be set in memory and the check engine light will come on immediately. If the light is not on, and there are no DTC's for the sensor in memory, the sensor is fine, don't mess with it. Just an FYI: If the crankshaft position sensor and or the timing cover is moved, removed, replaced, or disturbed in any way, the crankshaft position sensor relearn must be performed with a scan tool capable of initiating the relearn. If the relearn is not performed, the PCM will use the relearn data from the last relearn, which is now incorrect. The engine should still start and run, but injector timing, and ignition timing will both be incorrect.