97 XP mpem weirdness~~

[Mekanix]

Working on a side project 97 xp with a whole host of problems. Randomly it will decide to start with the key in on the post but before that it would be completely unresponsive to any input.

Sometimes I could connect the battery and and get a moment where the gauges would respond but only beep once when the key even approaches the post.
Sometimes it actually works perfectly and consistently but then decides randomly to stop doing that and just be unresponsive...

Ever seen an MPEM do this ?

I've replaced a bunch of questionable wires and reterminated most of the AMP plugs at the mpem. Voltage and continuity checks all are good, and I mean the whole harness.
IT really seems like its the mpem more than anything else at this point. Weird thing is that I have two of them and they both do the same thing. I mean almost identical.

When connecting the battery the first time the gauges respond and sometimes I can get the 2 beems from pressing start 5 times. Sometimes it does nothing and just times out, Other times it would just beep ones each time the key is brought near the mpem.

Then after what seems like 10 minutes it just starts working for no apparent reason and stays consistent until the next time it acts up.

 

[IDoSeaDoo]

Could it be your start push-button? Do you have another one to swap it out with to test? I've had keys get sensed before I attach them too btw.

 

[Mekanix]

Yup swapped out the button as well.
Actually swapped out the entire top console.
Its weird because it senses a key nearby but doesn't bother to wait untill the key is on before looking for it.
I thought the logic of the mpem was to wake up when a key was present, scan it and respond.
Not to respond and then say nope not even going to check for a key lol .

Even with the key on the post and the mpeme somewhat responding it still will beep first and then not even look for the key.

 

[IDoSeaDoo]

You got me... is this the same ski you found with the rebuilt top end having std pistons in the .50mm over cylinders? Quite the basket case you picked up

Have you measured the voltage at the fuses on the MPEM when it's playing dead?

 

[DJDaveOtt]

My 97 XP was acting up at the end of the season...gauges not working all the time, trim never worked, occasionally not recognizing the key, beep sometimes but not always. After busting the hood and having to replace it this winter, I decided to fix everything.
When I unplugged the wiring harness, I noticed a little corrosion in the plug end so I took apart the amp connector (plug end) to expose the actual metal sleeves and thoroughly cleaned with electronic cleaner on a q-tip each of the prongs on both the harness end and mpem then applied dielectric grease.
Once I plugged it back in, everything is working as it should! Maybe I just got lucky? Maybe you could too.. Can't hurt to look into that. I find it hard to believe you have 2 dead units.

 

[Mekanix]

I pulled the pluggs off and cleaned them still same issue. I'm thinking of retrofitting them with a 97 gtx mpem.

Where can I get the matting connector part number ?

I want to keep the stock harness but to make a drop in ready harness with a 97 all in one mpem. I know AMP make a the plugs but whay is the equivalent mating connector side... (I have several 96/97 mpem but no do mpem which is why I wanted to make a conversion harness.)

 

[Mekanix]

Well I found the original problem with the mpem. Bad solder joints everywhere!!!

First I picked at the corner on the back of the mpem and made a pocket where I could fit plastic scraper and pulled up all of the potting.
I found that the solder joints on the protection diode were separated as well as most of the pads were loose from the component legs.
After resoldering everything that looked bad I plugged it in and it worked perfectly and beeped consistently.
I think this one will be used again. I was so excited it worked that I didn't even try my scratch built computer.
Also reinstalled my engine and it ran pretty good.

 

[Matt Braley]

Nice save!

 

[Mekanix]

Well it's been a few rides now and so far completely stable.
I only have the back taped because I a really didn't expect it to work.

So now I'm pulling it back out and have to seal it.

What should I use ?
Thinking rtv or silicone or even make a clear backing our of lexan and only seal around the ends.

Now I have to deal with a pesky vts.
It trims down but won't come back up and then sometimes it works lol.
And there is no stop to the trim up so I popped the fuse a few times trummi g too far up. Im going to probably install a self resetting fuse inline to the motor for 3a.

 

[mikidymac]

I would just buy a good used VTS from Minnetonka4me and be done with it.

 

[Mekanix]

I'm actually going to see if I can rebuild this one with either new reed switches and new relays. Assuming I can get the potting out like the mpem.
And I plan on adding proper circuit breakers and manual up and down buttons to the unit that power directly to the motor.

Just because lol

But yeah if I keep this one I'll be getting a good one from Nick.

 

[Austrian Rotax]

The cheapest alternative for trim is a dei 451m relay, it worked perfect for my 99 spx. Many thread s on how to wire it up.

 

[Mekanix]

Thanks. I saw that and I was maybe going to use that but I'm curious if I can use an arduino instead. The position output to the gauges works so I was just going to wire in some relays to an arduino and have it cut out the relay when a specific current is reached as the motor binds at end stops for a brief second. Also i would add code so that it would disable any more movement in that direction untill the opposit direction is actuated.