how to test a crank position sensor
#1
how to test a crank position sensor
does anyone out there know of a way to test a crank position sensor to see if its sending a signal? please see my question under CUSTOM BIKES... "custom bike no start" for the reasons I need to find this out-I'm stumped-anyone out there with ign knowlage willing to take a stab at my problem?[sm=headbang.gif][sm=feedback.gif]
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bizzaro (09-04-2016)
#4
#5
RE: how to test a crank position sensor
ORIGINAL: MW2469
Thanks for the reply.what do I do if I can't lay my hands on a o'scope? Any other options?
Thanks for the reply.what do I do if I can't lay my hands on a o'scope? Any other options?
As the crankshaft rotates, the wheel teeth interrupt a magnetic field produced by a magnet within the sensor. The sensor's internal circuitry detects this and produces a signal which the ECM reads. The ECM uses this signal to accurately measure crankshaft velocity which is a variable used in order to detect misfire, spark and, fueling.
Looking at your service manual find the wire that goes to the B+ Measure from this wire to ground for the DC supply voltage. Measurement should be taken on the sensor side of the connector. Ground connection as well.
On my Dyna this wire is marked BK for Black. Do this test at rest and with the engine spinning. A loose connection could break as the motor shakes.
If you have voltage present with the key on and with the engine spinning move the positive meter lead to the Signal wire. This is marked R for Red on my Dyna. With the engine spinning you should see a voltage signal on that wire.
You should measure the signal at the sensor connector and the ecm to verify it is reaching the brain.
Good Luck
#6
fxdwg2002 at verizon dot net
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For those of you that don't know, 0v-5v is TTL logic used in 100% of digital circuitry. This is digital because the red wire and black wire are independent of any power source or ground on the bike.
Ok, I do not have an o'scope to test this with. But it is my understanding that the magnet in the CKP sensor will produce a 5v pulse every time the missing teeth come around. This can be seen on a multimeter as a change from zero (actually 2.81v) to 5v. Do I understand correctly?
It takes 2.81v just for the ECM to register the presence of the CKP sensor.
I kept the plug hooked up between the CKP and the ECM. I pushed straight pins into the connector so I could see the operation (or lack there of) in circuit.
Ok, I do not have an o'scope to test this with. But it is my understanding that the magnet in the CKP sensor will produce a 5v pulse every time the missing teeth come around. This can be seen on a multimeter as a change from zero (actually 2.81v) to 5v. Do I understand correctly?
It takes 2.81v just for the ECM to register the presence of the CKP sensor.
I kept the plug hooked up between the CKP and the ECM. I pushed straight pins into the connector so I could see the operation (or lack there of) in circuit.
Last edited by FXDWG2002; 08-18-2009 at 07:19 PM.
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For those of you that don't know, 0v-5v is TTL logic used in 100% of digital circuitry. This is digital because the red wire and black wire are independent of any power source or ground on the bike.
Ok, I do not have an o'scope to test this with. But it is my understanding that the magnet in the CKP sensor will produce a 5v pulse every time the missing teeth come around. This can be seen on a multimeter as a change from zero (actually 2.81v) to 5v. Do I understand correctly?
It takes 2.81v just for the ECM to register the presence of the CKP sensor.
I kept the plug hooked up between the CKP and the ECM. I pushed straight pins into the connector so I could see the operation (or lack there of) in circuit.
Ok, I do not have an o'scope to test this with. But it is my understanding that the magnet in the CKP sensor will produce a 5v pulse every time the missing teeth come around. This can be seen on a multimeter as a change from zero (actually 2.81v) to 5v. Do I understand correctly?
It takes 2.81v just for the ECM to register the presence of the CKP sensor.
I kept the plug hooked up between the CKP and the ECM. I pushed straight pins into the connector so I could see the operation (or lack there of) in circuit.
Ron