96 spx mpen testing

[Frige]

This the ski I bought that has been sitting forever. It will not turn over with the start button. I tested the button and the lanyard switch. At first the lanyard switch wasnt working but after clicking a bunch of times it is working. Still will not start. Anything else I should check before ordering a new mpen?

 

[artr]

Does the engine crank with the lanyard and start button? If not does it crank by shorting across the top big terminals of the start solenoid with an insulated handle screwdriver?

 

[Frige]

It will crank if I short the solenoid but not with the start button.

 

[artr]

You should download the 96 shop manual at seadoomanuals.net and look at the schematic for your ski. The manual will tell you if the gauges light up or the vts should work when the start button is pressed. If that works then it's a good sign the mpem is working.
If you think the start button and lanyard are working, then check the operation of the start solenoid. With the lanyard on and the start button pressed the mpem should supply a 12V signal and ground to the 2 small wires (yellow/red stripe and black) attached to the base of the solenoid which you can test for with a voltmeter. That should cause the solenoid to click and short the 2 large terminals on top together. If you see the 12V and ground control signals on the base but no 12V to the starter cable on the top, then replace the solenoid.
If you don't see the control signal on the base of the solenoid you need to retest the start button and lanyard switch. The schematic shows that each of those simply grounds a wire that goes to an mpem input which you can test for.

 

[Frige]

Thanks I will check the manual. There is no power going to the starter solenoid coil.

 

[Frige]

I printed page number 166 from the manual and I am going to check resistance on the mpen. I dont have the other tools besides my meter so that is as much as I can do.

 

[artr]

You can measure the resistance but I did that on my 96 GTX CDI module. It did not match on all lines but the module still worked, It was something else that was bad.
While it may be your mpem there are other simple tests you can do with your meter to check why the mpem seems to not work.
First check the 5A and 15A fuses on the mpem are good (should measure 0 ohms across fuse)
Next check the the mpem is getting 12V across the 2 red wires and the black ground wire that go to the mpem
If you seem to have problems with the 12V going to the mpem, disconnect the 3 wire connector to the VTS module. I've read when the VTS fails it can drag down the 12V.
There are places like Westside Powersports that test mpems and sell tested used replacements but I would be interested in your results of the above tests before replacing the mpem.

 

[Frige]

Well the resistance was way off. Some were not even close and a couple were open. So I ordered a new mpen. Wired it in and got 2 beeps as soon as I put the lanyard on. But no start. I am going to clean the connections and try again.