98 GTI, Dealer said MPEM is dead

[platinumtron]

I have ordered an MPEM and a Stator/Magneto Assembly. Should be here before the end of the week.

Hopefully one of them will fix it.

 

[platinumtron]

Well, the MPEM was the issue. 97+ GTI have a Digital CDI, unlike all previous models. Digital CDIs require components other than a Magneto and a Coil. Basic difference is, Models not using this MPEM work with AC voltage straight from the Magneto to the Coil. 97+ GTI MPEM converts the AC voltage from the magneto and converts it to DC. Hence the sometimes the reference to this system being a DC-CDI.

I work on electronics for a living, so a engineering breakdown of how the system works, is all i need to troubleshoot. I learned this difference on Monday after reviewing differences in the shop manual from 96, 97 and 98 GTIs. 97 and 98 are the beginning of Digital CDI in the 717. I found a theory of operation for a Digital CDI for a completely different product. Electronics typically don't get called the same name if they operate differently. This theory of operation noted parts of the system that are not in the magneto and the coil. They have to be in the MPEM.

The good news is i have an extremely cleaned out stator area so the metallic particles will not be causing a failure anytime soon. I Installed a new stator today. Then i tried for spark, and nothing was different. So because i ordered both parts, i also installed an MPEM, and she immediately had spark.

Thanks to all that helped. Those who didn't know, please take note so we can all better help others. The 97+ 717 Ignition does not work like a conventional 717 with a basic CDI where the MPEM only grounds the circuit.
references:
Freescale Semiconductor:
https://www.nxp.com/docs/en/application-note/AN4006.pdf
Seadoo Manuals
SeaDoo Manuals - FREE PDF Download!

 

[mac0611]

Thanks. I could see that the signal is coming from the MPEM from the schematic. I have a no spark problem on my 97 GTI I'm trying to troubleshoot. I replaced a known good coil to no avail. Do you know what voltage value I'm looking for on the white wire to the coil? Reading your post I should expect to see a DC value on the wire.

 

[platinumtron]

I can’t exactly recall what value it was, but it was in the seadoo manual for the particular ski.

 

[platinumtron]

if you are getting the ac voltage from the stator to the connector for the mpem, and no dc voltage at the coil then likely your mpem has failed you.

Aside from previously mentioned potential problems in the stator area. Metal shavings and rust can play havoc on a stator.

 

[mac0611]

if you are getting the ac voltage from the stator to the connector for the mpem, and no dc voltage at the coil then likely your mpem has failed you.

Aside from previously mentioned potential problems in the stator area. Metal shavings and rust can play havoc on a stator.

thanks for the reply.
I guess there is an A/D converter in the mpem. I have other problems to deal with and I just shut it down for the year. I'm going to pull the engine and do a complete inspection of the magneto and flywheel as well as changing out the fuel delivery to the carburetor. That crap got into the carburetor. I dont know if I might be better off getting a new carb for it if its still available.