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  1. #1

    Irregular injector voltage help please.

    Hi there I have a 2003 polaris msx 140 .The problem that I have is that it boggs down at 4000+ rpms then cuts out. Its starts straight back up and runs fine to the 4000 rpm mark.
    Tests ive done :
    changed tps.
    changed both air exhaust sensors.
    Ohmed stator as per workshop manual all good .
    checked 12 pin plug ac voltages pins 3 & 10 , 4 &9 , 5 & .8 all good.
    tested injector voltage while cracking all good 20v.
    idle volatage at injectors 45v all good.
    testing at 4000+rpm voltage drops at injectors to 28v I thought it had to be 45v constant.
    Have not send emm to dfi for check up.
    Any help would be appreciated thanks.


  2. #2

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    have you checked the fuel pressure

  3. #3
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by msx999 View Post
    Hi there I have a 2003 polaris msx 140 .The problem that I have is that it boggs down at 4000+ rpms then cuts out. Its starts straight back up and runs fine to the 4000 rpm mark.
    Tests ive done :
    changed tps.
    changed both air exhaust sensors.
    Ohmed stator as per workshop manual all good .
    checked 12 pin plug ac voltages pins 3 & 10 , 4 &9 , 5 & .8 all good.
    tested injector voltage while cracking all good 20v.
    idle volatage at injectors 45v all good.
    testing at 4000+rpm voltage drops at injectors to 28v I thought it had to be 45v constant.
    Have not send emm to dfi for check up.
    Any help would be appreciated thanks.
    Nicely characterized!

    How are you determining the 4000 RPM change? Are you slowly increasing the RPM while the engine is out of the water, on the trailer?

    The EMM power section internally switches from series to parallel rectification as RPM rises. My current understanding is that this occurs around 2500 RPM. If the series to parallel mode change occurs at the same RPM as your voltage drop then that would explain why it is happening.

    My current expectation is that your EMM needs repair.
    Last edited by K447; 11-13-2013 at 11:57 AM. Reason: EMM power section series to parallel change happens circa 2500RPM. 5500 is the change to Homogenous combustion.

  4. #4
    Thanks for ur quick responses. I thought it was the emm just needed someone elses advice. Cause its going to be a pain in the neck to find one here in Sydney Australia. No Dfi tec round here. Thanks

  5. #5
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by msx999 View Post
    Thanks for your quick responses. I thought it was the emm just needed someone elses advice.

    Cause its going to be a pain in the neck to find one here in Sydney Australia. No DFI tech round here. Thanks
    Hmmm. I think there WAS somebody down there that did component level repair on Ficht EMM. At least his own, if not for others. I would have to hunt for the old thread. Or you could hunt

    There are a handful of other Greenhulk members in Australia who have Polaris. A few even have the Ficht fuel injected versions. Some networking through them might get you some traction.

    Now, if you can find somebody who is 'local' and can do diagnostics and repair of surface mount (SMD) electronics at the component level, the info in the following thread may be enough to allow them to get it fixed.

    What is inside a Polaris Ficht EMM - 45 volt & 12 volt power section

  6. #6
    Update I sent emm away and they said all ok. Tested voltage again and the injector voltage drops at 5500 rpm doe anyone think it could be a stator or flywheel problem. As all sensors are new , new capacitor 39000uf and new tps

  7. #7
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by msx999 View Post
    Update I sent emm away and they said all ok. Tested voltage again and the injector voltage drops at 5500 rpm
    does anyone think it could be a stator or flywheel problem.
    As all sensors are new , new capacitor 39000uf and new tps
    5500 RPM is the point when the EMM switches from stratified to homogenous charge, if I am remembering correctly.

    Lemme check that ...
    Yep, it switches combustion modes at 5500 RPM

    So no repairs at all were done to the EMM? Which repair service did you send it to?

    It is always possible that there is some issue with the stator or flywheel, but in this case it seems unlikely.

  8. #8
    I sent it to the Australia division of emmrepair.com. He was 99 percent sure the emm was good because it was rebuilt 5 hours ago. I don't know the history of the ski I bought it broken . If it is the emm can that section be fixed ( stratified to homogenous ) . Do stators and flywheels go bad on the msx 140 very often. Thanks

  9. #9
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by msx999 View Post
    I sent it to the Australia division of emmrepair.com.

    He was 99 percent sure the emm was good because it was rebuilt 5 hours ago.

    I don't know the history of the ski I bought it broken. If it is the emm can that section be fixed ( stratified to homogenous ) .

    Do stators and flywheels go bad on the msx 140 very often. Thanks
    I am not familiar with the 'Australian Division'. Would you be able to Private Message the contact details, or post them here?

    I am not sure what 'rebuilding' means in terms of the EMM. Perhaps replacing some of the known failure prone components in addition to whatever parts are causing the original problem.

    The Ficht EMM can be tricky to bench test as they have multiple operating modes and of course the EMM interacts with the other parts of the running engine, including but not limited to the flywheel and stator.

    The 5500RPM aspect may just be coincidence regarding the combustion mode shift.

    Do you have access to another EMM, just for testing?

  10. #10
    I wish I did . not to many msx 140 around Sydney if anyone does could you let me know.

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