1997 GTX Electronic Module Short?

[KC chief]

First I want to thank everyone associated with this site. This is my first post but have been going on this site for years to keep my old Seadoo running and out of the scrap heap. I had mutiple issues this season and I think I solved them all but a short in the electrical system. I think it is in the electronic module but wanted some input before I layout the money for a new one. The last time I was out it was running like a champ for around an hour. It started to stall when more than idle throttle was applied. I finally got it to go full throttle and made it back to the ramp to pull it out. It stalled at the ramp and then would not turn over at all. Thought it was a dead battery. Charged the battery and it still would turn over. I rebuilt the carbs and replaced the fuel lines while it was out to take care of what I thought was a fuel issue, not running over idle. Starter and ignition coil all tested OK. Found that the start stop switch was bad and replaced.
When I connect the battery ground it sparks a bit. When I put the key in the display it comes up 12V low with maintenance light on, no beeps on the buzzer, but I had a spare and that doesn't beep either. Engine will turn over but the battery drains rapidly. Brand new battery, charged and reading 13V. I disconnected the negative battery cable and installed a test light from the engine ground to the negative battery post and it lights up. I started disconnecting plugs to try to isolate the circuit causing the ground. If I disconnect the red wire with purple stripe that plugs into the electronic module the test light goes out. I then jumpered the red purple wire from the rear electrical box up to the front electronic module to make sure it was not in the wiring harness and the short was still there.
Sorry for the wordy information. My question, based on all this information, can the electronic module short out internally and cause these issues? Is there anything else I should try to test or do before I bite the bullet on a new MPEM?

 

[POPPS]

What motor?

 

[KC chief]

What motor?

Its a 97 GTX 5642 with a 787 motor.

 

[KC chief]

Please Help.

 

[artr]

Did any fuses on the MPEM or rear electrical box blow? Do your gauges light up for 33 seconds if you just press the start button (no key on post) or if you put just put the key on the post? If it passes all that and cranks and starts it would hard to say there was a short in the MPEM.

If I understand the test you did, you disconnected the large black cable to the starter(engine ground) and put your test light inbetween it and battery negative and saw 12V on the large black starter cable. If that is the case, then remove the large red cable from the starter at the solenoid and repeat the test with the test light inbetween engine ground and the negative battery terminal. Also preform the tests in the service manual for resistance and shorts on the Magneto plug on the front of the engine.

 

[POPPS]

Wow!,,,how can there be 12 volts from the ground and negative terminal?,,,look forward to finding the issue,,,

 

[KC chief]

No fuses blew in rear or front electrical boxes. Yes. I was getting more than usual sparking when connecting the negative battery cable. So I just put the test light in between the negative ground strap that attaches to starter and the negative battery terminal and the light is constant. I started disconnecting plugs down stream from the rear electrical box until the light went out. When I unplugged the red wire with the purple stripe that runs from the rear electrical box to the MPEM, the test light went out. I will measure the actual voltage on the ground and advise. I will also answer your other questions when I get back home early in the week. Thanks for the response

 

[KC chief]

Ok. Back home. The gauge lights up when start button is pressed without key. It flashes 12v low with red maintenance light flashing for 30 seconds. The same thing happens with key in but engine turns over. Battery reads 13v and I placed the meter between the negative cable from starter and the negative battery post and reading 12.98v.
I also disconnected the red cable going to the starter at the solenoid and placed the test light between it and the negative battery terminal and the light came on. Just to be clear, only time any voltage is present at the negative battery post is when the red wire with the purple stripe is connected to the MPEM.
I then disconnected the magneto plug at the front of the engine and the test light turned off even with the red wire with the purple stripe connected to the MPEM. I think you were on the right track asking me to test out that plug. Can you point me in the right direction to find instructions on how to test for shorts at the magneto plug?
Thanks for your help.

 

[artr]

You can download the 97 service manual at seadoomanuals.net. The info you are looking for is in section 07-03-3. Since you probably don't have an adaptor, you will need to carefully probe into the connector on the magneto cover using the plug you take out for the wire color guide. Disconnect your battery before probing.

 

[KC chief]

Thank you. I found the instructions. Since I do not have the harness adapter, should try to probe on the pin side of the connector attached to the magneto housing (going to be very tough) or can I reconnect the plug and follow the wires into the front electrical box and probe them there?
Thanks again.

 

[artr]

If you can unplug the wires at the front electrical box it would be the next best thing. The extra wire length will add marginal resistance since you are measuring a fraction of an ohm. Short the leads of your ohmmeter set on the lowest scale and if the reading is not zero, subtract that reading from what you measure. In terms of measuring for shorts, it should be fine.

 

[KC chief]

OK. It passed the Stator continuity test. It failed the insulation test. I had continuity to ground on all three yellow pins. Makes sense that I was having the direct short. Do you think that fried the rectifier in the process?
That looks like a real bear to open up the magneto cover. Does that mean I need a new Stator plate assembly, p/n 290-886-588? How hard is that to replace? I really appreciate your help.

 

[artr]

Sorry, I have never preformed that type of repair. Maybe some of the members with that type of experience can offer their advice.