1999 Sea DOO GTX LTD Electrical Issues

[takeoff]

FYI I am a newby with jetskis but Im pretty handy with cars and motorcycles.

I just purchased a used 1999 Seadoo GTX LTD from a guy, I got a good deal on it, it needs a little love, but after putting a new battery in when I was buying it from the guy he showed me that it fired up it started and then died. The key was really finnicky and he said it might need to be replaced. I was able to negotiate based on the fact that it definitely needed to be tinkered with a bit, and the guy was positive that I would get it running with minimal effort, as last season his daughter used it a bunch.

Anyways a few weeks went by I put the battery on a tender, but when I put the key on and pressed start nothing happened, no gauges no beeps. I checked the fuses in the front they're all good, I tested the continuity on the key and everything checks out, I have continuity on the sides, and I get 6 ohms when I test the center with a side. I know the dess post could be bad potentially. I unplugged the dess post and tried to test it based on a youtube video I watched but Im not 100% sure what readings are out of tolerance for the DESS post.

Yesterday I tried again to regain some power, battery was tested for voltage and is still good, I opened the rear E box, and made sure the connections were tight in there (based on a post I saw on here), it seemed like one of the red wires was a little loose, so I tightened it down, and then put the key on and pressed the start/stop button my gauges actually came to life, audibly I got a single beep and a message for Low fuel warning on the dash, however there seems to be fuel in the tank. When the guy i bought it from went to start it up that day there was no low fuel warning/and we got a double chime and it actually cranked. Later in the day I went back to see if I still could press the button and get that single beep/low fuel warning it went back to being completely dark no gauges no beeps nothing (battery still had adequate voltage).

Before I go out there again to try to tinker with it, I wanted to see if I could get some guidance on here on where to begin.

Im wondering if its the fuel sender? or a bad dess post? or a bad starter solenoid? or even a bad MPEM (which is my biggest fear because its the most expensive of the bunch). Some help/guidance would be appreciated, If im not going to be able to get this bad boy running, I want to try to sell it and get something else before season starts.

Let me know where to start, Im new to jet skis but Im willing to put in the time on it, and willing to learn. Just need some guidance for this ski.

Thank you so much.

Update: Just went out there again and the battery is already down to 6.5 volts, any idea why the battery would discharge that quickly overnight? Temp outside mid 40s, its an AGM battery it was brand new when I bought the ski he went out and swapped the battery at the store. Could it be a bad battery?

 

[tobytd]

Possible bad battery… Load test?
Check and clean the grounds on the left front side of the motor… May not be the easiest things to get to under the pipe

 

[takeoff]

Possible bad battery… Load test?
Check and clean the grounds on the left front side of the motor… May not be the easiest things to get to under the pipe

whats the best way to clean them? based on the other things I was saying could anything else be problem?

 

[etemplet]

Are you removing and replacing the key a few times? They can be finicky. Most like to be snapped in... pressed firmly. Download a manual for the year ski it will tell you what readings you should have and how to test. The wiring diagram is in the last few pages of the manual. What you have is 3 wires coming off the Dess Post and the PLUG/CONNECTOR is right where the wires come out of the steering column. You can take your readings there. Also... unplug the magneto wiring harness and check it out and plug it back in. If that harness isn't making good contact the ski won't do anything.

You could have a problem with the holder relay, bad fuse, but I doubt that is the problem. Sometimes just unplugging and replugging the connectors does the trick. Remember they are old and get corroded and dirty.

Download the Manual - Here --> Seadoo Manuals Good Luck !!

 

[etemplet]

As for your fuel level, you need to test the baffle sending unit. A simple ohm check but it is a pain to get to. I just did one the other day but I had the baffle removed from the ski. I made a video I just posted. Here ya go. Seadoo Fuel Sending Unit Test

 

[ski-d00]

Jump the solenoid to see if the engine cranks over. If it cranks well, your battery is fine. If not, battery/connections/starter need diagnosed. That's where I would start.

The long single beep is usually a bad battery/connection/wrong key/bad connection on the post. It will never start until you get 2 beeps.

Unlikely the mpem is bad if you heard it run, unless you are jumping it or charging it while you are trying to start it which can fry it.

 

[Poormanracing]

First always remove the dess key and hold it a foot away from dess post and hold it away for a good 20 seconds.give it time to reset.if that doesn't work unplug the mag housing connector and clean it carefully on both sides.do the same on electrical box.if that don't work run another ground wire from battery to the block.to test baffle once the power gets figured out un plug the baffle it's a pink wire on one side and pink black tracer on the other just jump them on mpem side and see if gauge goes full.if full bad baffle if empty bad something else.load test battery forget about voltage.you can have all the voltage in the world if amps are not there it would t do anything

 

[takeoff]

Thank you for all the support so far. Again im new to this so im not 100% sure where/what some of the things you are saying are, but for starters I unplugged and tried to clean/reconnect most of the connectors including the ones on the mpem. I got a brand new battery that I hooked up, and I had no electronics whatsoever. One thing I did was I unplugged and replugged the wire pictured below, and then when I pressed the start button I would have a single beep and gauges came alive, but the ski gave a fuel low warning message as I stated previously. What is weird is if I took the key off the dess post, and put it back on then pressed the start button I got nothing. If I unplugged this wire in the picture, and replugged it in AGAIN then pressed the start button then the single beep and low fuel warning would come back and I had electronics again. Does this help with diagnosis at all?

 

[Poormanracing]

The dess post will hold a memory and stay energized if the dess is not far Away.i like to hold it Away for a few feet let it reset.then put dess cord on the post.wait for double beep then try and start button.

 

[SIMPLEARKANSAN]

I had the same issue on a 98 GTX LIMITED. I had two beeps but no gauge lights(gauge was dead). I replaced the starter solenoid and cleaned all connections in the rear electrical box. Mine seemed to not be making a good connection where the plug connected to the bottom of starter solenoid.

 

[SpitandDirt]

Thank you for all the support so far. Again im new to this so im not 100% sure where/what some of the things you are saying are, but for starters I unplugged and tried to clean/reconnect most of the connectors including the ones on the mpem. I got a brand new battery that I hooked up, and I had no electronics whatsoever. One thing I did was I unplugged and replugged the wire pictured below, and then when I pressed the start button I would have a single beep and gauges came alive, but the ski gave a fuel low warning message as I stated previously. What is weird is if I took the key off the dess post, and put it back on then pressed the start button I got nothing. If I unplugged this wire in the picture, and replugged it in AGAIN then pressed the start button then the single beep and low fuel warning would come back and I had electronics again. Does this help with diagnosis at all?

Feel free to Private Message me. I can walk you through your troubleshooting. Here are a couple of things you need to know: 1. The DESS post(where you install the key) is nothing more than contact points and a magnetically activated glass reed switch. There are no digital components inside the DESS post. It can be tested with a magnet and a multimeter. All the "magic" is happening inside the MPEM with the large connectors. On your particular unit, the MPEM (when everything is functioning correctly) will draw a small load from the battery while it is "looking" for a key. The connector you circled above is the power feed for the MPEM. Every time you unplug that connector, you are completely removing power from the MPEM. So, when you plug it back in, the MPEM is rebooting. Now, that said, unplugging that connnector is the easiest way to prevent the battery from being drained when the ski isn't in use.

But here is the kicker: The MPEM shouldn't kill the battery for at least days when the ski isn't in use. If it's draining a battery overnight or within 24 hours of being hooked up, there are more issues to check for. For one, on the MPEM, there are several fuses. The 15A will completely remove the charging system from the equation, which also sucks because the voltage regulator is PART OF the MPEM and can not be repaired. The good news is that the charging part of the MPEM can be bypassed by using an external voltage regulator.

Anyway, here is the lowdown....more and more of those particular MPEMs are starting to go bad. I can't tell you for certain if yours is already shot, as that would require a bit more conversation and exchange of pictures. I would start by studying the wiring diagram and locating your beeper. Disconnect it from the harness and zap it with full battery voltage. If it sounds off, it's good, if not, you need a new one. The beeper really needs to function in order to get all the information you can without resorting to buying a CanDooPro programmer -- which by the way will not do any advanced diagnostics because the MPEM does not support those functions. On your year, the CanDooPro can only adjust the ignition timing curve, program up to eight keys to be recognized, and read the true MPEM hour meter. As long as things haven't been swapped out, the MPEM retains the most accurate record of how many hours the engine has ran.

There is so much more to explain, but I only have enough time. Good luck, and shoot me any questions you have.