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  1. #1

    1999 GTX Limited Key problem

    Hello all,
    I just picked up a 1999 GTX Limited. Seems to start normal and run good for 15-20 minutes then all of a sudden it just shuts off. No matter what the speed, throttle setting, or water conditions it just shuts off.

    To get it to even crank over again I have to pull the lanyard key and plug it back in. The ski will run again for a while and shut off again. Each time it runs for less time.

    I know it must have something to do with the key. Do these keys have some kind of code or chip in them? Can this be converted to the old reliable ON/OFF "C" type lanyard switch??


  2. #2
    There are actually quite a few things that can cause the problem you are having. It even could be fuel starvation and have nothing to do with the key.

    But it is likely either the MPEM or the DESS post that is the problem. When you put the key on the post, there is a magnet in the key that actuates a tiny reed switch in the DESS post that turns on the MPEM. The MPEM then sends out a signal to the key, and it responds with its serial number. If that serial number matches the one programmed into the MPEM, then the MPEM becomes fully functional and allows the ski to run.

    However (and this is where there is a big misconception out there...) after that point, the key contacts serve no function whatsoever. It is simply the magnet in the key that keeps the reed switch closed.

    You could have either a weak magnet in the key or a bad reed switch in the DESS post, because once that circuit is broken, the MPEM shuts down.

    Question: What happens to the gauges when your ski shuts off?

  3. #3
    RumRunnerRon's Avatar
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    Quote Originally Posted by jsl750&slt750 View Post
    Hello all,
    I just picked up a 1999 GTX Limited. Seems to start normal and run good for 15-20 minutes then all of a sudden it just shuts off. No matter what the speed, throttle setting, or water conditions it just shuts off.

    To get it to even crank over again I have to pull the lanyard key and plug it back in. The ski will run again for a while and shut off again. Each time it runs for less time.

    I know it must have something to do with the key. Do these keys have some kind of code or chip in them? Can this be converted to the old reliable ON/OFF "C" type lanyard switch??

    When it shuts off does it look like you have lost all power/ info center goes blank? If you try to restart after it dies do you get any beeps or just silence. I know it will restart after re-seating the lanyard. I want to know what happens when you don't and try to restart. There is no way to convert (that I know of) to a non DESS lanyard.
    One thing to do is see if you can get it to do this (die) on the trailer/hose. When running it on the hose make sure to dribble water about every 1-2 min on the carbon seal. It will make working on it a little easier if you can do it on land.

  4. #4
    RumRunnerRon's Avatar
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    Quote Originally Posted by Sea Dood View Post
    There are actually quite a few things that can cause the problem you are having. It even could be fuel starvation and have nothing to do with the key.

    But it is likely either the MPEM or the DESS post that is the problem. When you put the key on the post, there is a magnet in the key that actuates a tiny reed switch in the DESS post that turns on the MPEM. The MPEM then sends out a signal to the key, and it responds with its serial number. If that serial number matches the one programmed into the MPEM, then the MPEM becomes fully functional and allows the ski to run.

    However (and this is where there is a big misconception out there...) after that point, the key contacts serve no function whatsoever. It is simply the magnet in the key that keeps the reed switch closed.

    You could have either a weak magnet in the key or a bad reed switch in the DESS post, because once that circuit is broken, the MPEM shuts down.

    Question: What happens to the gauges when your ski shuts off?

    Dood:
    Could it be possible to jump the blk/ylw wire to the ground while the lanyard is in place? If it is then it would isolate it down to either a faulty reed switch or lanyard. Provided that it doesn't die again.

  5. #5
    olds72's Avatar
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    I'm having a similar problem with mine, It will run like hell for 10 - 15 min and then shut down. I've been able to restart, not always having to remove the lanyard. I was also getting the low 12v warning. Are you getting this warning? I've found so far that my rectifier is not operating properly. Once the battery gets low, it doesn't have enough juice to operate the ski properly. Thus shutting it down. Last time I was out I was able to idle back in. If your ski is an RFI, they require a lot of juice to operate. Hope this helps.

  6. #6
    Quote Originally Posted by RumRunnerRon View Post
    When it shuts off does it look like you have lost all power/ info center goes blank? If you try to restart after it dies do you get any beeps or just silence. I know it will restart after re-seating the lanyard. I want to know what happens when you don't and try to restart. There is no way to convert (that I know of) to a non DESS lanyard.
    One thing to do is see if you can get it to do this (die) on the trailer/hose. When running it on the hose make sure to dribble water about every 1-2 min on the carbon seal. It will make working on it a little easier if you can do it on land.
    When it dies the display screen is black, nothing, yes like all power is lost. If I try to restart sometimes it will beep and just not crank. Other times I have to pull the lanyard, plug back in, it powers back up and I'll go again for a while. I have not been able to get it to restart or even crank over until the lanyard is reset, even with the beeps sometimes it still wont crank.

  7. #7
    RumRunnerRon's Avatar
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    Quote Originally Posted by jsl750&slt750 View Post
    When it dies the display screen is black, nothing, yes like all power is lost. If I try to restart sometimes it will beep and just not crank. Other times I have to pull the lanyard, plug back in, it powers back up and I'll go again for a while. I have not been able to get it to restart or even crank over until the lanyard is reset, even with the beeps sometimes it still wont crank.



    As Sea Dood mentioned earlier, about the DESS post and lanyard, this would be where I would look first. You can download a manual from here
    http://seadoomanuals.net/manuals/1999-seadoo.php

    There is not a lot of info on the DESS system but the schematic will be helpful. You should have 12v all the time on the blk wire with yellow stripe and the other black is ground for the reed switch. The magnet closes the circuit between these two wires. The third white wire with gray stripe transmits the key code. While I have not tried this yet I believe it's possible to to figure a way to jump the blk/ylw wire and ground together and use the lanyard to only transmit the code. Then if it does not die you would know that the problem is either the key or the post. If it does die then you would have to keep looking.

  8. #8
    I agree with Ron. If you can figure out a way of positively shorting the Black/Yellow and Black wires AFTER the ski is started, then you would learn if the DESS post is bad.

    (or you could short them, and keep the DESS post in place and quickly put on the key to read it before the accessory timer expires (within 33 seconds)

    Keep in mind if you short it, you wouldn't have the "dead-man" function of the safety lanyard if you fall off......

  9. #9
    RumRunnerRon's Avatar
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    Quote Originally Posted by Sea Dood View Post
    I agree with Ron. If you can figure out a way of positively shorting the Black/Yellow and Black wires AFTER the ski is started, then you would learn if the DESS post is bad.

    (or you could short them, and keep the DESS post in place and quickly put on the key to read it before the accessory timer expires (within 33 seconds)

    Keep in mind if you short it, you wouldn't have the "dead-man" function of the safety lanyard if you fall off......

    Yeah I would suggest they try to replicate the symptom on the trailer and if they can do that well it just would be better than having to take it for a ride. Thanks for verifying my thoughts on the jumper idea.

  10. #10
    before you go shorting wires there is a test to determine if the post is bad. black to black yellow should be open. with the key on there should be continuity. I think it is grey to the center post has cont. and black to the ring on the post should have continuity. that is how you test the post. I have a bad key, if I mess with it long enough while holding the start button it will sometimes start.

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