Bad Crank Position Sensor?
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Thread: Bad Crank Position Sensor?

  1. #1
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    Default Bad Crank Position Sensor?

    So I'm having this issue. I have a PCV with the POD 300 display. For some reason, the RPM keeps dropping to 0 for a moment. Not a problem on idle, but when I twist open the throttle, these 0 RPM signals cause the motor to spit and cough and drop power - PCV data shows it's not firing the injectors. Guys from Dynojet hooked up remotely and couldn't figure it out. Replaced the PCV - same problem. Replaced the TPS sensor - same problem. PCV wired to battery. Motor and frame well grounded. I was reading online faulty CKP sensors can have symptoms like this. Anyone ever hear of this? My damn bike has been down all summer. This sucks.

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    No F1 light at all? Might have to get it scanned to pull codes.

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    Very Active Member futurR's Avatar
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    To date, I have never heard of CPS going bad on a 9--- also known as a pick up sensor, reads the magneto behind the left side engine cover. Did you check the connectors for it? Under the secondary where the Regulator/rectifier is located. I believe the smaller black 2 wire connector.
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    Does it do it regularly where you can duplicate it when you want? If you hooked up a Suzuki scanner to it, could you not look at the data stream like a cars ECM?
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    Quote Originally Posted by futurR View Post
    To date, I have never heard of CPS going bad on a 9--- also known as a pick up sensor, reads the magneto behind the left side engine cover. Did you check the connectors for it? Under the secondary where the Regulator/rectifier is located. I believe the smaller black 2 wire connector.
    I will check that. Thank you.

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    No fault codes. I don't have a Suzuki scanner. My Power Commander logs data and what I see are RPM values dropping to zero momentarily and the injector pulse width also dropping to zero.

    UPDATE

    Inspected and cleaned all connections. No improvement. Going to pull apart the generator tomorrow.
    Last edited by Syler; 08-26-2020 at 08:46 PM.

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    Quote Originally Posted by futurR View Post
    To date, I have never heard of CPS going bad on a 9--- also known as a pick up sensor, reads the magneto behind the left side engine cover. Did you check the connectors for it? Under the secondary where the Regulator/rectifier is located. I believe the smaller black 2 wire connector.
    Is the CPS another name for the GPS (Gear Positions Sensor)? I do not think so, because I understand that the GPS is located under the right engine cover?
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    Quote Originally Posted by Dommy View Post
    Is the CPS another name for the GPS (Gear Positions Sensor)? I do not think so, because I understand that the GPS is located under the right engine cover?
    No, CPS is crankshaft position sensor, ECU uses it to know when to fire injectors and spark.

  11. #9

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    As said above, CPS do not go bad on the M109 very often. I was told mine was bad by mechanic and put in 3 of them( attaches to stator-have to replace whole unit). No improvement.
    Finally had bike scanned and GPS shows erratic behavior. Might want to check that too before going into the crankcase after the CPS. I hear that GPS go bad on 9’s and GSXR more often than CPS.

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    Quote Originally Posted by randyr View Post
    As said above, CPS do not go bad on the M109 very often. I was told mine was bad by mechanic and put in 3 of them( attaches to stator-have to replace whole unit). No improvement.
    Finally had bike scanned and GPS shows erratic behavior. Might want to check that too before going into the crankcase after the CPS. I hear that GPS go bad on 9’s and GSXR more often than CPS.
    I will have a look. Thanks.

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    Quote Originally Posted by randyr View Post
    As said above, CPS do not go bad on the M109 very often. I was told mine was bad by mechanic and put in 3 of them( attaches to stator-have to replace whole unit). No improvement.
    Finally had bike scanned and GPS shows erratic behavior. Might want to check that too before going into the crankcase after the CPS. I hear that GPS go bad on 9’s and GSXR more often than CPS.
    Gear position sensor? How would that cause the problem? Did you test your CKP sensor with a multi-meter at all?

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