Aftermarket MPEM on 1997 Challenger

[ToddinTO]

Hello fellow S2SBs (Seadoo 2 Stroke Boaters)

Helping out my brother-in-law with his "new" 1997 Seadoo Challenger with the single 787 engine.

MPEM is behaving very strangely;

• At power on, you can hear a relay click on the MPEM, and power is supplied to gauges immediately,
• Even after 33 seconds, sometimes, the power is still present, i.e. the timer to save battery power does not kick in and turn off the gauge power,
• If the key is placed on the post, sometimes you will receive two beeps, sometimes just one,
• cleaned and checked the DESS post all the way back to the wires going into the MPEM, all good, reed switch in the post is good and consistent, so the post has NOT been replaced,
• If two beeps are heard, the engine will usually start after a few seconds of cranking, can run for a few secs or even up to you push the stop button or pull the key,
• when it does quit on its own, it seems as if you have pushed the stop or pulled the key, power stays on the gauges, but will no longer beep or crank, even if the key is removed and replaced, no beep,
• Need to remove power to the battery for a few mins and try again, if the relay click is heard it is usually good to try again, but sometimes no click is heard,

So far we have done . . . .

1. Cleaned and checked all cables and wires (connectors and 0 ohms resistance in wires), confirmed good grounds and no corrosion,
2. All fuses are good, no blown ones, just to be safe, put known good fuses on the MPEM,
3. Ran new positive and ground wires from battery direct to MPEM,
4. Tried multiple keys,
5. All the pins and connectors for the large plug going to MPEM have been cleaned as well,
6. Seems to be more intermittent when it is cooler, more stable when it is warmer,
7. Beginning to think there is a faulty component in the MPEM power supply, but the unit is not welcoming to component surgery due to all the potting/epoxy encasing it. I have no reluctance to perform component repair, as I have done so on many older circuit boards, this one just has the challenge of the epoxy on everything,
8. There are services which will take an MPEM from a PWC with the 787 engine and adapt it to work on the Challenger, but those are about 1K USD,
9. Considering finding a used 787 MPEM from a 1997 GTX (~500USD), adding the connectors to match the Challenger harness, or . . . perhaps one of the ArielTek SD287s which is an aftermarket MPEM for 787s (~300USD) and adapting it for the boat.

There are statements that the adaption of the PWC MPEM to the boat will render the neutral start switch inoperative, but if the switch is wired in series with the line to the starter solenoid that should re-enable the safety feature.

I could not find any references to anyone using an aftermarket MPEM in a Seadoo boat, but I see no reason why it would not work with the 787 in the Challenger, am I missing something?

 

[mikidymac]

Contact Westside Powersports Seadoo. @Minnetonka4me

 

[Edson Henriquez]

Hello fellow S2SBs (Seadoo 2 Stroke Boaters)

Helping out my brother-in-law with his "new" 1997 Seadoo Challenger with the single 787 engine.

MPEM is behaving very strangely;

• At power on, you can hear a relay click on the MPEM, and power is supplied to gauges immediately,
• Even after 33 seconds, sometimes, the power is still present, i.e. the timer to save battery power does not kick in and turn off the gauge power,
• If the key is placed on the post, sometimes you will receive two beeps, sometimes just one,
• cleaned and checked the DESS post all the way back to the wires going into the MPEM, all good, reed switch in the post is good and consistent, so the post has NOT been replaced,
• If two beeps are heard, the engine will usually start after a few seconds of cranking, can run for a few secs or even up to you push the stop button or pull the key,
• when it does quit on its own, it seems as if you have pushed the stop or pulled the key, power stays on the gauges, but will no longer beep or crank, even if the key is removed and replaced, no beep,
• Need to remove power to the battery for a few mins and try again, if the relay click is heard it is usually good to try again, but sometimes no click is heard,

So far we have done . . . .

1. Cleaned and checked all cables and wires (connectors and 0 ohms resistance in wires), confirmed good grounds and no corrosion,
2. All fuses are good, no blown ones, just to be safe, put known good fuses on the MPEM,
3. Ran new positive and ground wires from battery direct to MPEM,
4. Tried multiple keys,
5. All the pins and connectors for the large plug going to MPEM have been cleaned as well,
6. Seems to be more intermittent when it is cooler, more stable when it is warmer,
7. Beginning to think there is a faulty component in the MPEM power supply, but the unit is not welcoming to component surgery due to all the potting/epoxy encasing it. I have no reluctance to perform component repair, as I have done so on many older circuit boards, this one just has the challenge of the epoxy on everything,
8. There are services which will take an MPEM from a PWC with the 787 engine and adapt it to work on the Challenger, but those are about 1K USD,
9. Considering finding a used 787 MPEM from a 1997 GTX (~500USD), adding the connectors to match the Challenger harness, or . . . perhaps one of the ArielTek SD287s which is an aftermarket MPEM for 787s (~300USD) and adapting it for the boat.

There are statements that the adaption of the PWC MPEM to the boat will render the neutral start switch inoperative, but if the switch is wired in series with the line to the starter solenoid that should re-enable the safety feature.

I could not find any references to anyone using an aftermarket MPEM in a Seadoo boat, but I see no reason why it would not work with the 787 in the Challenger, am I missing something?

Hi I’m considering buying an aftermarket MPEM for 1997 challenge 787. Did all tests to find spark problem and no spark..

Did you buy and aftermarket MPEM.?
If you did from where?

 

[ToddinTO]

Hi Edison, before replacing the MPEM, have you confirmed the coil is NOT receiving the signal from the MPEM?
It is the white wire coming off the MPEM, check it to ground, it will have a brief 12v pulse when you crank the engine, may need an oscilloscope to see the voltage. You may also see it with a 12v light probe, but test in a dimly lit area, otherwise you won’t see the light as it is so short duration.
IF the coil is not receiving the pulse then ya, sounds like the MPEM.
Do you hear the two beeps when you put the key on the post? Should at least hear one!
If the beeper is not working, get it working first, if you do put in the aftermarket MPEM, you need the beeper to program it.
Also, be sure to trim back the spark plug wires where they go into the boots by 1/4” or so and check they are inserted firmly.
When checking for spark, also do that in a low light area, i have found on the 787, even with the new coil, sparks are not really that bright!
If you decide on a new aftermarket, the one I purchased was from Bay Area Powersports, Arieltek SD287

CDI MPEM Ignition Module Sea Doo SPX 97 98 99 1997 1998 1999

using the wiring diagrams from the new MPEM and the boat, I cut out the old MPEM and crimped in some bullet connectors so the new MPEM could just be plugged in. Even was able to preserve the safety switch to ensure the boat is in neutral when starting!!!
The boat started and ran great!
Issue now is that when the rectifier is connected, it blows the 5amp fuse at every start, replace the fuse and it starts again just fine, replacement rectifier is on order…..

 

[Edson Henriquez]

Hi Edison, before replacing the MPEM, have you confirmed the coil is NOT receiving the signal from the MPEM?
It is the white wire coming off the MPEM, check it to ground, it will have a brief 12v pulse when you crank the engine, may need an oscilloscope to see the voltage. You may also see it with a 12v light probe, but test in a dimly lit area, otherwise you won’t see the light as it is so short duration.
IF the coil is not receiving the pulse then ya, sounds like the MPEM.
Do you hear the two beeps when you put the key on the post? Should at least hear one!
If the beeper is not working, get it working first, if you do put in the aftermarket MPEM, you need the beeper to program it.
Also, be sure to trim back the spark plug wires where they go into the boots by 1/4” or so and check they are inserted firmly.
When checking for spark, also do that in a low light area, i have found on the 787, even with the new coil, sparks are not really that bright!
If you decide on a new aftermarket, the one I purchased was from Bay Area Powersports, Arieltek SD287

CDI MPEM Ignition Module Sea Doo SPX 97 98 99 1997 1998 1999

using the wiring diagrams from the new MPEM and the boat, I cut out the old MPEM and crimped in some bullet connectors so the new MPEM could just be plugged in. Even was able to preserve the safety switch to ensure the boat is in neutral when starting!!!
The boat started and ran great!
Issue now is that when the rectifier is connected, it blows the 5amp fuse at every start, replace the fuse and it starts again just fine, replacement rectifier is on order…..

Hi TODD thanks for answering this quick… I see you live in Toronto …? I live in Quebec …

I have not confirmed that the coil is receiving signal from the MPEM yet
And have not confirmed if the mpem is sending right info to the trigger coil through female 6 pin connecter that attaches to mag/stator housing ( do you know how I can test that ?)

The boat beeps 2x and turns over real well…
The engine and carbs where rebuilt in 2021 and since then the boat has just been sitting In my yard …

We never figured out the NO spark problem
And got cut up with other stuff..

I don’t have a oscilloscope but could borrow one temporarily unless a test lamp would work to do the test off the white wire coming from
The mpem…

Should I disconnect it and put that test light to it and turn engine over ?

On thing I know is that we even took a workkt coil and wires and boots from another same boat that has 2 engines
And no spark
So we know it’s not the coil the problem

Haven’t checked the spark in low light areas but the dude helping me did cover up the spark plug to make it darker to see if spark..

I have considered the arieltek but for the 1997 GTX
It seems to be easier to install than the one you have for the SPX

 

[Edson Henriquez]

Hi TODD thanks for answering this quick… I see you live in Toronto …? I live in Quebec …

I have not confirmed that the coil is receiving signal from the MPEM yet
And have not confirmed if the mpem is sending right info to the trigger coil through female 6 pin connecter that attaches to mag/stator housing ( do you know how I can test that ?)

The boat beeps 2x and turns over real well…
The engine and carbs where rebuilt in 2021 and since then the boat has just been sitting In my yard …

We never figured out the NO spark problem
And got cut up with other stuff..

I don’t have a oscilloscope but could borrow one temporarily unless a test lamp would work to do the test off the white wire coming from
The mpem…

Should I disconnect it and put that test light to it and turn engine over ?

On thing I know is that we even took a workkt coil and wires and boots from another same boat that has 2 engines
And no spark
So we know it’s not the coil the problem

Haven’t checked the spark in low light areas but the dude helping me did cover up the spark plug to make it darker to see if spark..

I have considered the arieltek but for the 1997 GTX
It seems to be easier to install than the one you have for the SPX
may also send my mpem to my friend who has the same boat and he will put it into his boat and see if it gets it started..



One sure way to find out if it works



Please respond again thanks

 

[ToddinTO]

Yes, I am in Toronto, but I sometimes travel to Quebec, specifically, Montreal.

Sorry, I may have sent you the incorrect link, the Arieltek I used was indeed for a 1997 GTX with the 787, here is link to the manufacturer’s website product page

MSD-08 – Arieltek

Sounds like you are asking about the continuity check for the cable/connectors, you can do that with a digital multimeter on the resistance setting. Connect one probe to the wire from the MPEM, and the other to the lug that connects to the coil.
Resistance should be ZERO Ohms.
In the case of the 1997 Seadoo Challenger the coil is in the same case as the MPEM so no harness between the two.
Double check all your grounds are good, from battery to engine/starter, and to the coil, bad grounds can cause all sorts of issues, on PWCs and boats!!!
Sometimes there will be corrosion inside the connector boot, a continuity check for the wires, connectors will identify that.

 

[Edson Henriquez]

Hey brother thanks for answering
Yeah I want to avoid the MSD because that would mean it’s not plug and play right?
It has to be wired into the existing connectio to DESS key ?
And it’s more expensive than a used or repaired MPEM

Thanks for the tips on the continuity Check etc
And Gonna recheck my grounds

If you have anymore help or ideas let me know please …. I plan to send my MPEM to a friend who can put it in his challenger 787 and see if he gets spark ..
Then I will know for sure if mine is good

The mpem beeps 2x and turns the engine but not spark as off now

 

[ToddinTO]

Glad to help, if you would prefer, send me a DM and i will give you my phone number and we can chat…
The Arieltek unit does NOT need to be programmed, will work with any key, it just uses the magnet in the key to sense if it is connected or not.
I had checked into “working” Seadoo MPEMs for replacement, but they were 2-3K USD!!! And a PWC one rewired for use with the boat was 1000USD!!!
In the case of my brother in laws boat, the MPEM seemed very flakey depending upon the temp, not reliable at all, i am in the process of carefully removing all the epoxy from it to determine the questionable. component, I expect it will be something in the power supply. Just using a SMT hot air gun to soften the material, then it flakes off at about 200F or so, i do a little bit here and there, no big rush….

 

[ToddinTO]

 

[ToddinTO]

View attachment 63544View attachment 63546

 

[ToddinTO]

View attachment 63544

 

[Edson Henriquez]

Glad to help, if you would prefer, send me a DM and i will give you my phone number and we can chat…
The Arieltek unit does NOT need to be programmed, will work with any key, it just uses the magnet in the key to sense if it is connected or not.
I had checked into “working” Seadoo MPEMs for replacement, but they were 2-3K USD!!! And a PWC one rewired for use with the boat was 1000USD!!!
In the case of my brother in laws boat, the MPEM seemed very flakey depending upon the temp, not reliable at all, i am in the process of carefully removing all the epoxy from it to determine the questionable. component, I expect it will be something in the power supply. Just using a SMT hot air gun to soften the material, then it flakes off at about 200F or so, i do a little bit here and there, no big rush….

How do I send you a DM?
My cell is 418-957-9828 add me on WhatsApp or add me on facebook
I sent you my picture and name on Facebook
Would really like to connect and see if you could help .. thank you so much