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how to test a crank position sensor

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  #11  
Old 11-24-2009, 10:05 PM
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Piniongear, I hope you still monitor this thread. Would you mind sending me that Crank Position Sensor procedure to me?
 
  #12  
Old 11-28-2009, 09:50 PM
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If your tach reads approx 300 RPM while cranking, your crank sensor is working. To test for a crank signal with a multimeter, switch meter to 'AC Volts'. measure from sensor ground to signal wires, should read at least 5V AC while cranking.
 
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Old 11-28-2009, 11:25 PM
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You can use a ohm meter to check resistance with the sensor unplugged, it is a coiled magnet and b+ to sensor ground has specs to produce a correct signal, b+ to sensor base is a short to ground test. It would be how helpful a dealership would be to give the specs for the resistance test.
The paperclip tests give voltage output numbers but still need to know the out of range specs of that test.
 
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Old 12-19-2009, 11:10 AM
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TONS OF BAD INFO ON THIS THREAD! NONE OF WHAT WAS MENTIONED SO FAR IS CORRECT.

1. there is no batt voltage to the CKP, period
2. the pulse is not a pulse but a constant a/c voltage PRODUCED by the ckp sensor itself
3. the drop in a/c voltage caused by the missing tooth tells the ecm what part of the stoke the engine is on, and the slow down of the crank (upon compression), and lower a/c voltage tells the ecm what phase the engine is on.
4. the only way to test the ckp, is to UNPLUG it from the ecm, put a multimeter on the 2 wires, (R/B and B) and crank the engine. it should show 1-5 VA/C.
5. this is hit or miss, some ckp show good when they are not, but if it shows bad, it is.
 
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  #15  
Old 12-19-2009, 01:25 PM
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Originally Posted by jmetro
TONS OF BAD INFO ON THIS THREAD! NONE OF WHAT WAS MENTIONED SO FAR IS CORRECT.

1. there is no batt voltage to the CKP, period
2. the pulse is not a pulse but a constant a/c voltage PRODUCED by the ckp sensor itself
3. the drop in a/c voltage caused by the missing tooth tells the ecm what part of the stoke the engine is on, and the slow down of the crank (upon compression), and lower a/c voltage tells the ecm what phase the engine is on.
4. the only way to test the ckp, is to UNPLUG it from the ecm, put a multimeter on the 2 wires, (R/B and B) and crank the engine. it should show 1-5 VA/C.
5. this is hit or miss, some ckp show good when they are not, but if it shows bad, it is.
JMETRO,
thanks for the information.
 
  #16  
Old 12-19-2009, 01:54 PM
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Restistance is X 100 scale, should read 10. That's what my 07 softail is, if that helps. 5 volt ac pulse when cranking.
Ron
 
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  #17  
Old 12-19-2009, 04:20 PM
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Crank sensor is kind of alternator. Crank sensor has 1 coil, Harley alternator has 2 coils, rest of bikes 3 coils.
 
  #18  
Old 05-08-2010, 12:24 PM
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I would just like to thank FXDWG 2002 for your input on how to test a crankshaft position sensor. It worked for me and saved me money when needed. My bikes up and running at a minamal cost. Thank You, and this forum for everything. Really Appreciated... Popjoe!!!!!!
 
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Old 03-01-2012, 10:25 AM
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Default don't need a scope

Originally Posted by MW2469
Thanks for the reply.what do I do if I can't lay my hands on a o'scope? Any other options?
Go to Radio shack, buy a 5 volt LED for $2.00, time response is fast so you can see the pulsing, works great - a lot chaeper than an oscilloscope..Mike
 
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Old 03-08-2014, 07:07 PM
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Originally Posted by Muhran
Go to Radio shack, buy a 5 volt LED for $2.00, time response is fast so you can see the pulsing, works great - a lot chaeper than an oscilloscope..Mike
This is brilliant. If you happen to have a camshaft position sensor (My 2000 FLHR-EFI does) this method works for it too. It can be difficult to hold a multi-meter and try to read a voltage. Get the 5 volt led and solder a short length of wire (pigtail) onto each terminal, then a small alligator clip on each of the other 2 ends. Unplug the ckp harness, connect the alligator clips and viola'. I also use this method to ck injector harnesses.
 


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