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  1. #1

    MPEM, ECU, DESS knowledge needed...

    Can someone please explain the electrical system for the early 4-tecs?
    without me going to the manual please...
    What are the major functions of the MPEM?
    " " " ECU?
    and how does DESS work? is it in the ECU? is it in the MPEM? both?

    to my knowledge if you swap out ecu`s - you also need to have lanyard programmed to it...

    so do you have to re-program lanyards if the MPEM is swapped out or replaced?
    ...PR...
    Last edited by Pale Rider; 09-30-2007 at 07:33 PM.


  2. #2
    cbrich's Avatar
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    The ECU is the brains of the engine, it control the two most important part of the engine, the fuel and spark system, it tells the injector to fire and for how long depending on you right hand (it's realy the TPS). The ECU also controls the advancing and retarding of the spark by the cam and/or crank sensor. The ECU also get more information from other sensors, ie coolant sensor, oil pressure, exhaust temperature, and others.

    Not for sure on the DESS or MPEM. I think the DESS is the part of the lanyard. Shibby knows more about this

  3. #3
    EZ Dock of Long Island Shibby1485's Avatar
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    you can change the MPEM without reprogramming keys

    the ECU is engine management AND security on your ski... stores keys and contains all mapping for fuel, spark, timing, etc...

    the ECU is powered up thru the MPEM.. basically anything that gets power gets it from the MPEM on MPEM equipped skis... all the constant 12V common wires to the coils, injectors, ECU, etc etc come from the MPEM... that is the fuse center for constant 12V power.

    the ECU is the trigger... the other wire on the coils, injectors, etc is pulsed by the ECU

    Keys are strictly thru ECU, not the MPEM on 4-tecs... on 2-strokes DESS was thru the MPEM

    06-07 is where things start to get a little funny and twisty with wiring... but what i explained above is common for all 4-tecs 02-05

    on 06+ skis... the gauge is actually it's own onboard computer that gets programmed to the ski... different ballgame

  4. #4
    cbrich's Avatar
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    Way too complicated, there should be somekind of standard.

  5. #5
    awesome responses, thanks guys! this is a big help! ...PR...

  6. #6
    jaycee's Avatar
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    MPEM stands for.....???

  7. #7
    seadoor's Avatar
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    really cool

  8. #8

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    Multi-Purpose Electronic Module

    You could have had that Googled before you were done typing!

  9. #9
    jaycee's Avatar
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    Quote Originally Posted by VX1 View Post
    You could have had that Googled before you were done typing!

    But that's no fun....


    And just to be a douchebag I googled it to see what comes up...

    Sure as the grass is green the first three links showed the answer...
    Appreciate the answer anyways!!

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