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  1. #1
    theswits's Avatar
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    2005 STX 12F computer plus other PROBLEMS

    Continuing to work through some issues an a pair of 2005 STX 12F's.

    I tried getting into the "dealer mode" to see if my ECU had any error or diagnostic codes present. I held the "set" and "mode" buttons down simultaneously for more than three seconds, but the displays didn't change at all.

    If everything is OK, is there something on the display that will change when it goes into "dealer mode"?

    Here's the problems I have been having: I have two "identical" 2005 STX 12Fs. One runs great, the other doesn't.

    Differences:
    1) When I turn the key switch ON, the good ski beeps twice as the display goes through the self test, and beeps twice again when the ski is ready to start. The bad ski, doesn't beep at all, but the display goes through the same self-test in the same amount of time (same lights flash, etc.).
    2) The bad ski registers 0 MPH all the time. I swapped speedos between the two skis, and the speedo sensor is ok, bad ski still has 0 MPH all the time.
    3) The bad ski won't rev past about 5000 RPM (seems to be some sort of limiter cutting in), and confirmed it is not in SLO mode
    4) All other display functions on the bad ski work correctly (or at least the same as the good ski)
    5) The spark plugs on the bad ski look like it is running rich. Could that be related to a timing or EFI issue from the CDI computer not getting the right information from the "system computer"?

    Any other ideas anyone? I took it to a local dealer who said "yep, the display computer isn't working correctly", but they couldn't defintively say that was the problem and wanted to swap computers between the two skis to see if that fixed the problem (Gee thanks, at $90/hour to figure out if that was even the problem).

    So, I took the skis home, took the display out of the bad ski, plugged it into the good ski, same problems with the display. Seems to suggest the display is bad. What I didn't do is take the display out of the good ski, and plug it into the bad ski to see if that would make it work.

    I have had some suggestions that the source of my problem (decribed below) is the display/meter assembly computer. It was suggested that the display/meter assembly computer, which takes in the speedometer signal, also sends a feedback signal to the ECU (the engine control computer).

    So, the reason for the ECU limiting my revs to about 5000 rpm is because it's not seeing any speed signal from the display/meter assembly computer.

    If this was true, wouldn't all skis behave this way when they are "running on a hose"? If the ski is on the hose, it doesn't get a speed signal, does it?

    I did a few of the diagnostic tests suggested in the manual, and the end result is that it says "change the meter assembly module". (For instance, the reason the speedo isn't working is that it isn't getting a supply voltage out of the display module, same with the beeper).

    Can anyone confirm if the ECU computer is using the speedometer signal in some way that could affect the retard/advance timiing, the FI mix, or cutting in a rev limiter?

    Can anyone point me to a knowledgeable Kawasaki tech that could help answer some of these questions? My local guy hasn't worked on that many sleds of this type, and is mostly following the manual himself.


    Thanks in advance for any help!
    Last edited by theswits; 09-12-2007 at 11:25 PM. Reason: More applicable title


  2. #2
    theswits's Avatar
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    Update on STX 12f computer problems, NOW runs slow

    Hi folks,
    Well, I have an update on my woes with a 2005 STX 12f.

    OKAY, so I bought a new display computer (pricey mother). After installing it, the display now beeps during the power-on self test, and the the speedometer now works!

    BUT, the ski still won't go to full speed. It won't rev past 5000 rpm, and it reaches that at 1/4 throttle. Also, it doesn't seem like it likes to idle. It will idle for 2 or 3 seconds and then stall.

    Any ideas of where to look for the next problem???

    Could this be the ignition computer????

    Any help appreciated. Thanks, E.

  3. #3
    mirror's Avatar
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    I had the coupling for my exhaust split where I couldn't see it and it limited my rpms and made it stall. I didn't have any power either. It probably won't help but make sure you don't have an exhaust leak down at the coupling for the exhaust manifold to the water box. I thought I had blown my engine it ran so bad.

  4. #4
    theswits's Avatar
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    About the exhaust Leak

    OK, now you've got me interested.

    My coupling from the manifold to the exhaust box looks like it is in bad shape. I noticed this the other day, but I wnated to get it running well before I looked after the "minor" things.

    So what's the deal with the leaky coupling? Why does that limit the engine revs? Any info you can provide is appreciated!

    Cheers, E.

  5. #5
    if the exhaust is leaking ,
    when the engine is running it will suck in the fumes from the exhaust in to the air filter .this will then smuther the engine as it is not getting enough air to run correctly

  6. #6
    mirror's Avatar
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    The other half of the problem is no back pressure. Without back pressure your engine will not run properly. At high RPMs your valves are practically open the same time during the cycle so if you let the air in and out too easily you would lose compression. I am not a mechanic but this is my assumption of back pressure. Definitely something you want to check. I really thought I had eaten a piston it was running so badly. The only thing that made me question is was the ski would idle fairly well.

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