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  1. #1

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    MSX140 Cranking but not firing

    Had a great day on the ski yesterday. No issues at all. Went to flush it today...

    - Attached hose
    - Started engine
    - Ran for 5 seconds then stalled. Possibly gave a "pop" or "bang" when stalling, but hard to tell.

    Hasn't fired since.

    - No NGI display is shown during cranking.
    - Can't see a spark, but I've never tried this before so may be doing it incorrectly. (I rested a connected spark plug on an exposed bolt and cranked - no spark).

    Last edited by tsf; 09-12-2016 at 02:11 PM.


  2. #2
    Resident electronics hacker UnityRacing's Avatar
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    I'm assuming you have the lanyard connected. I know I've forgotten in the past.
    You can pickup a spark tester at most auto parts stores for cheap. It goes between your spark plug and lead and will light up when it's sparking. Great visual.

  3. #3

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    Thanks. Yes lanyard is connected unfortunately. That would have been a nice fix . Ordered a spark plug tester but not too hopeful about seeing a spark. Feels like the post-cranking electrics have shut down.

    I think I've seen a post somewhere that suggests if the ngi display doesn't switch on during cranking, then could be serious.

  4. #4
    Moderator HiPeRcO's Avatar
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    Check your CPS

  5. #5

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    Quote Originally Posted by HiPeRcO View Post
    Check your CPS
    Thanks. I'm assuming that must be a crank position sensor. Where is it and how do I test it?

  6. #6
    Moderator HiPeRcO's Avatar
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    On the top of the flywheel housing. Unbolt it and pull it out and inpect for debris. Also unplug it and measure impedance, I forget what it should measure but not open.

  7. #7

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    Thanks - I'll check it tomorrow. Would it be useful to measure the cps voltage during cranking too? Can this be done with the cps unplugged from the emm?

  8. #8
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by tsf View Post
    Thanks - I'll check it tomorrow. Would it be useful to measure the cps voltage during cranking too? Can this be done with the cps unplugged from the emm?
    CPS has specification for ohms but not for AC voltage output. The CPS is powered by the EMM.

  9. #9

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    Thanks. Removed and cleaned cps. Reads 140 ohm.

    Still not firing or getting power to the NGI display.

    Anything else to try?

  10. #10
    Resident electronics hacker UnityRacing's Avatar
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    Could be a faulty EMM. Could also be your flywheel key sheared. Pull the flywheel and inspect, or send the EMM in for repair/testing (if you don't have another to test with)

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