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Thread: K75S - Will not start but RPM gauge registers RPMs without engine

  1. #16
    A bozo on the bus deilenberger's Avatar
    Join Date
    Mar 2003
    Location
    Spring Lake NJ, USA
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    8,469
    Hi,

    Just dropped in for a moment. The RPM gauge registering RPMs without the engine running - to me - points to one thing. The Hall-Effect sensor is going kaput. The wiring on it deteriorates and eventually starts sparking between the wires. That gives the symptom of the tachometer reading when the engine isn't running. The Hall-Effect sensor is responsible for: (1) tachometer signal (2) signal that turns the fuel pump on (3) trigger for the ignition system.

    Usual failure starts when the bike is hot - and it just stops - then when it cools down it runs again. In this case it sounds as if either the sensor itself has gone bad or the wiring from it to the ignition module under the tank has gone bad. That module is under the main frame tube right behind the steering head. Were the wires you moved in that area?

    Just a few thoughts.. hope they help.
    Don Eilenberger http://www.eilenberger.net
    Spring Lk Heights NJ NJ Shore BMW Riders
    '12 R1200R - I love this bike!

  2. #17
    Registered User heejrbmw's Avatar
    Join Date
    Aug 2009
    Location
    Boone, NC (Mountains of Western North Carolina)
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    190
    Quote Originally Posted by deilenberger View Post

    Were the wires you moved in that area?
    No, I did not have the gas tank off and only moved the wires at and near the connector for the fuel pump which can be reached at the right rear side of the gas tank.

    One new issue I just noticed is that the oil light does not light with key "on" before pushing the start button. It may have nothing to do with it.

    Ed
    Ed Evans - - Semper Fi
    '94 K75 '92 K75S
    "Always do more than expected." Coach Jerry Moore, ASU

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