crank sensor and what it senses

[Sully]

I finally got somewhere with my truck today. I recreated my wiring harness for the crank sensor. Still got nothing. I hooked the scanner up and it was reading 0rpm while cranking. We tried moving a screwdriver across the front of the sensor and got varying rpms. So the pcm was seeing the sensor and talking fine. The truck even had good spark when "jerking off" the crank sensor and turning the key to crank it over.

What am I missing then?

 

[Sully]

the gear thingy (i cant think of the damn name of it) is solid in there and turns with the engine. Further more, the old crank sensor has a scratch on it. What could cause this to go bad all of a sudden?

 

[DRAGGIN95]

It's called a reluctor wheel, that's wierd about the crank sensor having a scratch on it like that, sound's like you are making some headway though!

 

[Sully]

yeah I thought of it as soon as I shut my computer down for the night. LOL

 

[Sully]

here is a pic of the old crank sensor

You must be registered for see images attach

 

[Sully]

reluctor ring from gm is roughly 25 bucks after tax.... that not too bad. I just need to figure out if that the part I need or if something else is going on.

 

[Sully]

Is there a way to clearance the sensor on the reluctor? The new sensor isnt getting damaged in any way, and the reluctor isnt moving any on the shaft. Visually its doing exactly what its supposed to. I have never swapped one of the crank sensors in this motor before, shouldnt it lock in some how other than the one little bolt? I have alsways known these type of sensors to kinda click into place like seating a fuel injector. This one isnt. Neither the old one or the new one does. They fall out if I dont hold them in place while putting the screw in.

 

[DRAGGIN95]

The couple of those that I have installed didn't pop in at all, I could feel the Oring seating, but no until the bolt was in there was nothing to hold it in, personally I have never seen or heard of a reluctor wheel failing, I'd be more prone to want to get a new from gm only or from salvage yard crank sensor, anyway it sure does sound like that where your problem's are coming from.

 

[Sully]

im going to try clearancing my timing chain cover I think. Take a few thou off, try it, and repeat as needed. If it doesnt work, im in the same boat as I am now.

Also, my truck will get spark with all of my original parts in it; coil, ignition module, crank sensor, and pcm. It must be something to do with the clearancing on my reluctor ring. I found the specs to be .020 max and .012 min... so I will see what I get now and file a bit here and there till I get the proper clearance on it. Worst case I need a new timing chain cover because I filed mine down wrong.... but if I swap the reluctor ring I will need a new cover anyway.

 

[Mike]

alignment and spacing on the sensor is critical