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crank sensor bench testing

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turboadict

New Member
Joined
Sep 7, 2006
Messages
68
I've got a crank sensor that I got with a bunch of parts and wondered how to electrically test it for correct operation - other than putting it on the car.

Are there any set values that you should be able to read accross the pins with a meter?
 
crank sensor testing

I will look up some stuff when I get home tonight. -Anthony P
 
OK here goes….I do not believe that there is a simple and straight forward bench test to determine a faulty crank sensor. A bad crank sensor would be suspect if the engine cranks but doesn’t start and all other components of C3I system are OK, no code 41 or 42 is present and the fuel system is OK. I’ve also heard that a bad crank sensor can cause a loud backfire through the throttle body while cranking the engine.

As long as the sensor is not physically damaged it either works or it doesn’t. A misadjusted sensor or a bent interrupter ring would rub and damage the vanes on the sensor causing a rough idle, poor performance, or a no start condition. Clearance of 0.025” is required on either side of the interrupter ring. From the Buick shop manual, “ A crank sensor that is damaged due to mispositioning or a bent interrupter ring, can result in a hesitation, sag, stumble, or dieseling condition. To determine if the crank sensor is at fault, scan engine rpm while driving. An erratic display indicates that a proper reference pulse has not been received by the ECM, which may be the result of a malfunctioning crank sensor.” -Anthony P
 
Great info, thanks Anthony.

stuck a meter on ot tonight, this is what I got:

with the sensor plug towards you and the ribs upwards, the only reading I got was the left and middle pin resistence - @ 4.8 M ohms.

Any one got a healthy one for comparison?
 
Great info, thanks Anthony.

stuck a meter on ot tonight, this is what I got:

with the sensor plug towards you and the ribs upwards, the only reading I got was the left and middle pin resistence - @ 4.8 M ohms.

Any one got a known good one for comparison?
 
You need to test the thing the way it's used in the car.

Power +10 volts d.c. from a good supply on Pin A, ground from the supply on Pin C, and put a scope on Pin B reading that to ground, or a voltmeter for a quick test.

Then put a piece of metal roughly the thickness of the crank ring back and forth accross the thing using the factory gap spec. listed above.

You should get a nice square wave out of it if it works, switches on and off with metal and no metal in front of it.

If you really want to know how well it's gonna work you have to do it really often and really fast. ;)
 
Think I'll put some voltage through it and see if it gives an on/off signal with a piece of metal going through it.

If it checks out that way, I'll file it away as probably works and test it on the car when I have some spare time on my hands.

The things you do when the weathers bad and you're bored.

Thanks for the info.
 
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