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  1. #1

    2004 MSX140 only has spark on 1 coil

    Hello....first time posting here but have lurked for a few years.

    I purchased a 2004 MSX140 a couple of weeks ago. Original owner stated he was running the ski on the lake when it shut down on him. He towed it to shore loaded it up and took it home. He was able to get it to run a bit, it was really rough.
    I went to look at buying it. It fired a bit, and with the throttle open while cranking was able to start and Rev up, but I could tell it wasn't quite right. I purchased it and a single trailer and drove them 200 miles home. When I tried to start it at my house it would crank but not fire.

    He said he was messing with the 8 pin connector on the computer, so that is where I started.
    - I see white red pin on connector side has a brown ring suggesting it has gotten hot.
    - cleaned computer connections with electric contact cleaner.
    - tested for spark, only PTO side has spark, I used all 3 plugs and all 3 wires in all 3 locations and only PTO has spark with all combinations.
    - unplugged tps, won't start
    - CPS reads 146 ohms
    - crank voltage to injectors is 28v PTO, 28v Mid, 27v Mag
    - crank voltage of 10.8v, after charging for a bit 11v
    - if I ground fuel pump I hear it run. I hear it run for 1 or 2 seconds after crank cycle ends.
    - display wakes up after cranking, displaying mph and time.
    - once I had a check engine result on the display, but I think I didn't have the 8pin connection in all the way. Check engine is currently not displayed.

    - I didn't check fuel pressure, I need to buy a tester.
    - didn't think it would be the regulator as it has spark to 1
    - might just be coils, but for them to go bad at same time and fact PO had it running seems unlikely.

    - ? Is there a test for the signal wire to the coil
    - ? Any other ideas

    Probably need to send the computer in for a test. I just want to test what I can on my end before I send that out to be tested.

    Thank you in advance, this sit is very helpful in the way it was intended to be, unlike what snowest has become. Thanks again!

  2. #2
    Click avatar for tech links/info K447's Avatar
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    Welcome.

    Bookmark this web site. Lots of useful info.
    http://polarispwcknowledge.shorturl....t-things-to-do

    28 volts on white/red wire suggests the EMM is not attempting to operate all the Ficht fuel injectors. Note that unplugging any of the white/red wires can change the measured voltage. Our injector voltage diagnostics expect all injectors are plugged in.

    Ficht fuel injectors are actually electrically powered pulsed high pressure fuel pumps. Each injector requires significant electrical power to operate. When all three injectors are operating the expected voltage on white/red wire is around 21-23 volts DC.

    The burned white/red wire on the 8-pin plug needs to be corrected. The white/red wires from the EMM deliver the ‘injector voltage’ to the injectors and back to the ignition control half of the EMM. There is no internal link between the EMM power sections and the EMM engine control section. The EMM power section receives AC energy from the Ficht stator inside the flywheel and generates injector voltage.

    I would be suspecting that one or two of the injector driver circuits inside the EMM has failed.

    There are some additional diagnostics that can be done.
    Do you have access to another Ficht three cylinder PWC?

    The easiest path is to remove the EMM and have it inspected by Lakeside Tech.

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  4. #3
    Moderator HiPeRcO's Avatar
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    There is certain EMM failure mode that causes the EMM to reset every time it tries to fire an ignition coil. So I suspect that this is what it happening, since as K447 noted the injector volts when cranking are higher than to be expected. In this scenario, it may not even be firing the PTO injector before the EMM is reset and starts again to try to synchronize with the cranking engine (thus not firing the other two injectors either). I (via Lakeside Tech) can test the EMM.

  5. #4
    Thank you for the fast replies.
    I will retest those voltages at the injectors with a better meter and verify those values are accurate.

    If so, I will send you my computer and have it tested. I will order a new connector and get the pins replaced and repaired.

    I do not have access to another MSX140. I only have a SLT750, as far as Polaris machines.

    Thanks again!

  6. #5
    Does the coil signal come from the stator or the MME? I understand that the voltage is high for the injectors, how does that translate into producing spark at 1 coil but not the other 2?

  7. #6
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by jjmyzrider View Post
    Does the coil signal come from the stator or the EMM?

    I understand that the voltage is high for the injectors, how does that translate into producing spark at 1 coil but not the other 2?
    On a Ficht engine the stator only supplies AC energy to the EMM. The EMM converts that to DC power and then uses it to run everything on the engine.

    The EMM runs the entire ignition system, and the fuel injection system. There are sensors on the engine that feed into the EMM for flywheel timing, exhaust water jacket and air intake temperature.

    Inside the Ficht EMM are three separate sections, one for each cylinder. Each section has a driver for the fuel injector and a driver for the ignition coil. There are also some shared circuits.

    The EMM also switches the fuel pump on and off, but the power for the fuel pump comes from the 12 volt battery.

    The EMM power section also provides 12 volt battery charging through two other pins on that same 8-pin connector.


    You can do some diagnostics by connecting the working ignition coil to each of the other primary ignition coil wires. If the coil still produces spark then those EMM ignition circuits are probably good. If the other coils do not produce spark but the original coil still does then the other coils have failed. Ignition coil failure can happen but that is not a common failure mode.

    EMM failure is more likely.

  8. #7
    I re-tested those injector voltages, yeah confirmed to be 28v.
    I did not take the time to move coils around, I assumed that the computer would need repaired either way. So k will ship the computer off and have it tested.

    Thanks.


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