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  1. #1

    Polaris MXS 140 idle only

    This is a 2003 model. Occasionally it will decelerate to idle speed and will not respond to throttle. If I shut it off and restart, it will usaually run fine for at least a while perhaps the rest of the ride. It may be going into limp mode but I'm unfamiliar with this recently acquired PWC.
    Can anyone give me some insight on this? Thanks.


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    My first suspicion would be the TPS sensor. Without a reliable signal from the throttle position sensor the EMM can become confused.

    It could be something else but having a known good/spare TPS on hand is not a bad thing.

  3. #3
    K447, thanks for the reply. The info I researched indicated a TPS may be the culprit but I was also looking for a 2nd opinion.

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    GGG's Avatar
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    I agree with k447. Although whenever i have come across this issue, it is not intermittent. It seems like the problem. You can unplug the sensor and see if you end up with the same exact symptoms. If so, its either the sensor, the wiring, or the emm. It is the cheapest and easiest fix so it is well worth changing on a hunch. It is near impossible to test something intermittent.

  5. #5
    GGG thanks. Good idea trying to isolate the problem by un-pluging the TPS.

  6. #6
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by rce54 View Post
    GGG thanks. Good idea trying to isolate the problem by un-pluging the TPS.
    So the problem is that sometimes the engine will just drop to idle and stay there, ignoring the throttle lever, correct?

    If that is the case, not sure what unplugging the TPS is going to tell you. With TPS unplugged the engine is guaranteed to not respond to the throttle lever.

  7. #7
    GGG's Avatar
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    The reason being to replicate the EXACT symptom. not responding to throttle can be interpreted in different ways by different people. Such as a person telling you "it wont turn over" when they really mean its cranking but wont start. A bad or unplugged tps is going to be more of a bog. Just makes more intake noise and doesnt rev up. As opposed to a low speed rev limiter or ignition trouble. which would cause the engine to shake more. Shit I've had people tell me it wont go past idle to find out the driveshaft is stripped and its bouncing off the limiter at 7k

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  9. #8
    Quote Originally Posted by K447 View Post
    Quote Originally Posted by rce54 View Post
    GGG thanks. Good idea trying to isolate the problem by un-pluging the TPS.
    So the problem is that sometimes the engine will just drop to idle and stay there, ignoring the throttle lever, correct?
    Yes, that is what happens. It will suddenly drop to idle and ignore throttle. The idle sounds normal without any misfiring. When I attempt to accelerate, I would expect it to lean out and stall because the throttle plates are opening with no fuel being added but it just remains idling with no sound variation. As mentioned earlier, restarting clears the problem and it runs normal again for anywhere from a while to all day.
    Last edited by K447; 09-24-2014 at 09:36 PM.

  10. #9
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by rce54 View Post
    Quote Originally Posted by K447 View Post
    Quote Originally Posted by rce54 View Post
    GGG thanks. Good idea trying to isolate the problem by un-pluging the TPS.
    So the problem is that sometimes the engine will just drop to idle and stay there, ignoring the throttle lever, correct?
    Yes, that is what happens. It will suddenly drop to idle and ignore throttle. The idle sounds normal without any misfiring.

    When I attempt to accelerate, I would expect it to lean out and stall because the throttle plates are opening with no fuel being added but it just remains idling with no sound variation.

    As mentioned earlier, restarting clears the problem and it runs normal again for anywhere from a while to all day.
    Ficht engines can handle the extra air from opening the throttle and still maintain the idle. That is how it manages to work despite the huge holes in the throttle plates

    Think of it like a Diesel engine. It injects just enough fuel to run the engine at the RPM the EMM wants it to run at. If it is the TPS failing or the EMM internally deciding to hold the engine at idle, it will do so.


  11. #10
    GGG's Avatar
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    The only thing that is strange is that I thought that if you unplug the TPS while the ski is running, youll have the problem described but if you plug it back it, it should just run fine again without having to restart. But like k447 said, its cheap enough to change and have on hand. Its either change that or the EMM. Big price difference

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