Bad DESS post????

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Sharkwhit88

New Member
I have a 2012 GTX 155 with a power issue. The power relay in the fuse box is staying powered and engaged with no DESS key attached. It is setting a P1658 code. If I put the relay in it will click and cluster will power up and beep. If I then attach the DESS key it wont start. If I leave the DESS key attached remove the relay and reinstall it will beep twice and allow me to start it. I have replaced the relay thinking it was stuck, no help. Disconnecting the battery or removing the relay is the only way to power down the ski. Could the DESS post reed switch be stuck on?
 
Replaced the dess post worked for one day. Same thing has returned. I have to pull the relay to power it down. Any ideas?
 
Was it a OEM DESS post? If something fixes a problem and then it doesn't anymore I would expect that the something was bad again. On the 2012 it would be more likely the start/stop switch than the DESS post. Sounds like it could be stuck in the on position. If things are right the start button should power up the gauges and then the dess key is attached with two beeps and then it should start. Could also be a bad diode in the rectifier, which can be tested, and last but not least the dreaded ECM could be faulty but that's after you are sure its nothing else is wrong.
 
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Not familiar with the diode, the start stop switch seems like an easy fix. the dess post reed switch works because if you pull the key off while running the engine will stop. Just stays powered and won’t restart without a power swap relay in and out. I would think if the start switch was bad it would engage the starter on power swaps with key attached? Thanks for the help not much on the internet with this problem.
 
I think the ECM needs to know the ski is off before it will send the ground signal to the start circuit, so if it never receives a stop signal from the switch it will stay in run mode until you pull the relay.
The three diodes in the rectifier keep current from back flowing from the battery to the start circuit. If one is bad the power up circuit will stay live until the relay or breaker is pulled.
 
skiasylum said:
I think the ECM needs to know the ski is off before it will send the ground signal to the start circuit, so if it never receives a stop signal from the switch it will stay in run mode until you pull the relay.
The three diodes in the rectifier keep current from back flowing from the battery to the start circuit. If one is bad the power up circuit will stay live until the relay or breaker is pulled.
Click to expand...
Is the rectifier part of the voltage regulator?
 
97 Seadoo gsi owned 3 years and burnt myself out with the terrible dess key issues.

This evening I finally took time to figure out how to wire in my dess key permanently and also wired in a generic marine kill switch and lanyard (needs to be normally open). Everything works perfectly gauges/start/stop/beeps/etc.
$20 for the safety kill switch and lanyard. No other purchases necessary.

If interested I'll send out my doodle diagram or photos.
 
Here's what I did. Then, just use a N.O. kill and put between number 1 and solid black wire. When the lanyard is pulled, it will open the circuit by removing that ground signal.

Pictures are from testing, not my final setup, obviously cleaned wires up nice and marine Shrink wrapped everything.
Cheers.
 

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Jaysurfsalot said:
97 Seadoo gsi owned 3 years and burnt myself out with the terrible dess key issues.

This evening I finally took time to figure out how to wire in my dess key permanently and also wired in a generic marine kill switch and lanyard (needs to be normally open). Everything works perfectly gauges/start/stop/beeps/etc.
$20 for the safety kill switch and lanyard. No other purchases necessary.

If interested I'll send out my doodle diagram or photos.
Click to expand...
Bro that’s freaking genius I’ve been wondering if anybody did something like this. Next is to see if anybody bypasses the MPEM all together
 
I could bypass it for sure it's actually really simple. The only type of engine ecu that's nearly impossible to bypass is fuel injected timed by the ecu. Stroked engines are timed by the flywheel (spark) and the carb (that thin plate that spins with the engine behind the carb, can't remember the name though.)
 
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But honestly, with the dess issue out of the way, I don't even care to bypass it since it's working flawlessly now. That damn dess...
 
Stevie96xp said:
Bro that’s freaking genius I’ve been wondering if anybody did something like this. Next is to see if anybody bypasses the MPEM all together
Click to expand...
I know I searched everywhere online for anyone to share the secret but no one's done it or claims it's not possible. I had to share I really feel for all the many dess owners out there. Everything is possible if you put your mind to it. 🤔
 
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For the engine to run it needs first,

fuel: (mechanically done and timed by the thin metal disc behind the carbs) we are good there.

Spark : Mechanically timed and sent by the flywheel coils/magnets. We are good there, just cut and run the 2 wires from the stator directly to the coil and then coil to plugs. Now we are good there.

Start : now have to run a curcuit from battery - to starter, and battery positive to a n.o. momentary switch, and from same switch to solenoid +, solenoid - to battery -, solenoid main+ to battery, solenoid main+ to starter +. We are good there.

Stop: easiest method is to use a dpst switch and have a wire going to battery - then jumped to each isolated pair on dpst switch, and a wire from first pair on dpst switch to plug 1,and a wire from second pair on dpst switch to plug 2 (this type of switch has 4 connections, each pair isolated from each other, see left illustration). When pressed, grounds spark killing engine. We are good there.

Lanyard kill requires a cup of coffee and some thought if anyone wants it.
 
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If anyone is going to do this and bypass the MPEM entirely, ask and I'll take the time to write up a really nice legible electrical diagram in full detail.
 
Jaysurfsalot said:
I know I searched everywhere online for anyone to share the secret but no one's done it or claims it's not possible. I had to share I really feel for all the many dess owners out there. Everything is possible if you put your mind to it. 🤔
Click to expand...
Yeah man that’s awesome I appreciate your knowledge I thought about doing it to mine but figured na since it still works. If it ant Broke don’t fix it I suppose 🤣
 
Jaysurfsalot said:
I could bypass it for sure it's actually really simple. The only type of engine ecu that's nearly impossible to bypass is fuel injected timed by the ecu. Stroked engines are timed by the flywheel (spark) and the carb (that thin plate that spins with the engine behind the carb, can't remember the name though.)
Click to expand...
Yeah I would think that would be complicated
 
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