'97 GTI refuses to start/run

[SeaDoosFriend]

I'm posting for a friend who has (2) identical Sea Doos. One of them will not turn over/crank/start, and the other one starts/runs just fine. A few days ago I helped him in trying to debug the situation. We swapped, one at a time, every conceivable part, including the main wiring harness, and the one that would run, continued to start just fine. We swapped out the MPEM, rectifier, Starter solenoid/ignition module, which includes the coil, Safety switch.

When one tries to start the "bad" one, nothing happens, no cranking, nothing. The starter will crank when jumpered on the solenoid. He seems to think that the safety switch has some sort of chip in it, although I see no evidence of that in the full manual that he has.

We ohmed out the black/yellow from the computer to the starter plug, disassembled the main plug on the computer connector and ohmed out all the wires we could, went through the safety switch and starter button, ohming procedure (he already bought a new starter button also, which we double checked) .. and all works as trouble shooting instructions indicate.

I have a background in HVAC, and pretty much understand wiring diagrams, etc., and am an engineer, and he's a fairly sharp guy too... but dang.... this just doesn't make sense to either of us.

I already read about "bad ground" previously posted, and he pulled all black wires he could find and assured that they were well grounded, including the main one off the battery.

Any ideas, guys ???

 

[Bills86e]

Eliminate things. It cranks when solenoid lugs jumpered, means solenoid faulty or
no start button. Consult your Shop manual preceedure to ohm that to eliminte.
Remove the starter and LOAD test. Usually auto part stores do that for free. Bills86e

 

[hwoolfolk]

When you jump a solenoid and it cranks that means the solenoid is at fault?

Question... do you get the beeps when you hook up the lanyard?

 

[Bills86e]

Yes. one beep, wrong lanyard. Two beeps, Ready for starting.
There are three wires going to the DESS post
Digitally Encoded Security System
- White/Gray
- Black/Yellow
- Black

The black wire is ground. The other two wires use the black wire as common.

Here is what happens when you put a key on the post. There is a small reed switch in the post that connects to the black/yellow and black wire. The key has a magnet in it, so it closes the reed switch, effectively shorting the black/yellow and black wires together.

This turns on the MPEM. It begins sending out a signal on the White/Gray wire. The center post of the DESS post is connected to the White/Gray wire, and when you put the key on, it makes contact with both the center post and the ring on the post, which is connected to the black wire (ground) This signal "turns on" the key, and it sends the serial number of the key to the MPEM over the White/Gray wire. The MPEM reads this serial number, and if it matches one of the key serial numbers stored in memory, it activates the MPEM which sends out the two beeps. Once this happens, the key circuit is shut off. It no longer has any function, except that the magnet is needed to keep the MPEM alive. The short between Black/Yellow and Black must always be present to keep the ski running.

A lot of times I see recommendations to clean the key, for people that have problem with the ski quitting while running. This is inappropriate advice; cleaning is only recommended if the ski will not start.

The 97 XP is known for corrosion problems with the MPEM connectors due to the stupid location they put the MPEM.

Water getting into the rear box can shut a ski down. Bills86e

 

[hwoolfolk]

WOW! That explains the DESS to a "T". Now I will have to re-read it 9 more times to thoroughly understand it... draw a picture as well. hmmm ... unless you have an exploded view picture to see all that you said?

So.. in my case where I am not getting a beep at all.. I can ground out these 3 wires to see if maybe the actual switch is the fault. Cuz.. if it was the key I would get an error beep.... right?

 

[jedro52]

2002 GTX won't do anything

I have a similar problem with my 02 GTX. Plug the lanyard in nothing. Can anyone tell me where the MPEM is located on at 02 GTX so I can check the 5 amp fuse.

 

[SeaDoosFriend]

Thanks, Bills, ... I sent this along to my buddy.. he says he will work on it tomorrow and will let ya'll know what happens. I guess he was right about the "electronic" part of the key/lanyard... I'd have never guessed. It's not in the book, as far as I can tell...