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    Default Understanding the 951 DI/DI-LE

    Understanding the Sea-Doo 951 DI & 951 DI LE



    The 951 DI and DI LE are the most Difficult Motors to diagnose Because they rely on many different sensors and relays to run the motor. To diagnose this motor, it is necessary to have the appropriate diagnostic software and a few specialty tools. Unfortunately only a certified Sea-Doo dealer has this software.



    There are 13 different sensors ( inputs) that relay information to the MPEM ( Multi-purpose Electronic Module). This MPEM sends the gathered information out to 9 different items to allow the motor to run.



    List of the 13 inputs that send info to the MPEM

    1) Throttle position sensor (TPS)

    2) Crankshaft speed sensor (CPS)

    3) Water temp sensor (WTS)

    4) Manifold air pressure sensor (MAPS)

    5) Manifold air temp sensor (MATS)

    6) Exhaust gas temp sensor (EGTS)

    7) Knock sensor (KS)

    8) Battery voltage (BV)

    9) Digitally encoded security system (DESS)

    10) Start/stop switch

    11) Oil tank low level

    12) Fuel tank low level

    13) Communication port



    List of Outputs to the engine (these enable the engine to run).



    1) Fuel pump relay

    2) Fuel injectors (2)

    3) Direct injectors (3)

    4) Rave solenoid

    5) Starter solenoid

    6) Ignition

    7) Beeper

    8) Information center

    9) Communication port



    There are 4 wiring harness connectors that all share the same style end, this is confusing and a problem if they are plugged into the wrong sensors. In some cases they will throw a code and in some cases they may not.( LABLE EVERY THING BEFORE DISCONNECTING).



    The 951 DI and DI-LE both use an air compressor to operate the RAVE valves and to supply the air needed for fuel atomization in the air injectors. There is a solenoid that is mounted to the side of the hull that is controlled by the MPEM to allow the rave valves to open and close at specific times. The MPEM also tells the air and fuel injectors when to open and close. If there is a malfunction with an air injector or fuel injector it can cause a cylinder to run a lean condition and server damage to the engine will occur.



    The fuel pump for this engine is mounted in the fuel tank and has two filters that are known for clogging up. If they clog, not enough fuel will cause to watercraft to run very sluggish, the same as if a fuel pump is failing.



    Low battery voltage will rev limit the water craft and in some cases will not allow it to start. Battery voltage must maintain a minimum of 10.5 volts while cranking for the electrical system to operate properly, many people assume that since the watercraft is turning over that it should start, this is not true.



    Replacing a short block in to the 951 DI and the DI-LE is not difficult, the difficult part of this engine swap is finding out why the first engine failed. Some engines fail just because they get old and they wear out, but the majority of these engines fail from faulty sensors and fuel related issues such as broken air injectors and faulty fuel injectors. All of these items should be tested by a Sea-Doo dealer on Sea-Doos diagnostic soft ware before the watercraft is taken for its first trip to the water.



    Remember that it is extremely important to use a factory repair manual as reference when performing any type of engine swap.
    Last edited by Ericka-SBT; 03-08-2011 at 05:45 PM.

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