2006 AJ290 350 mag mpi wiring questions

Discussion in 'Gas Engines/Drives/Transmissions/Props' started by William Miller, Jul 13, 2020.

  1. William Miller

    William Miller Member

    250
    Mar 16, 2007
    Darnestown, Maryland
    290 AJ
    Twin Mercruiser 300 hp Bravo III
    FIRST...PICTURES TO COME

    I have rebuilt and reinstalled the engines.
    Most of the wiring connections were tagged but i have a few connectors I need clarification on what they are for and where they connect. I think we can figure this out with your help.

    1. Trim limit and sender were replaced. Typical 2 wire puck type. The limit switch no problem... The sender switch has the two leads that go to the engine harness where there are 3 single wires with bullet connectors, so there is a choice. One labeled transmission temp/ trim. 2nd is Analog trim. Third is Digital trim. I anticipated that it was analog trim.....but.... on one engine that "female' connector had a rubber plug in it. Can anyone explain the difference to help me make the correct choice? Looked on the engine wiring diagram.


    2. There is a single pink wire with a bosch style connector which i think may be the wire that sends power to the fuel valve on the fuel tanks. This is shown on the Sea Ray wiring diagram where it shows it connects to the ecm. I cant figure out where.... Same both engines.

    3. Last there is two pairs of wires that ran next to the pink one out of the boat harness. Ill get the color. One set is female connector and the other is male. They look like they should connect together. The sea ray digram has something simular that has something to do with a fuel pump. My engine has cool fuel 3 which has a connector thats already hooked up and working. Both engines bench tested ran great.

    Any help with any of these questions would be great.
    I can imagine that with all the engine options for this boat that there are several wires that are unused as well.

    Thanks for the help.

    Very close to getting this project wrapped up and get back on the water!
     
  2. William Miller

    William Miller Member

    250
    Mar 16, 2007
    Darnestown, Maryland
    290 AJ
    Twin Mercruiser 300 hp Bravo III
    20200714_154939.jpg
     
  3. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    Agree that some wires go nowhere. So what doesn't work?
     
  4. William Miller

    William Miller Member

    250
    Mar 16, 2007
    Darnestown, Maryland
    290 AJ
    Twin Mercruiser 300 hp Bravo III
    Thanks for the reply.
    First. Both engines ran on the bench with just a few jumpers to the round plug and an oil pressure gauge hooked up.

    This picture is from the wiring diagram from sea ray. These wires come from the boat harness not found on the engine side.
    I think they might be for the diesel engine lift pump. If it had one.
    Mine are 350 mag mpi.

    My fuel pump runs from the engine harnes that has its own relay.

    I think these are redundant. Maybe they were taped up.

    20200714_132259.jpg
     
  5. William Miller

    William Miller Member

    250
    Mar 16, 2007
    Darnestown, Maryland
    290 AJ
    Twin Mercruiser 300 hp Bravo III
    This shows the single pink wire connected to the ecm. There is no place to plug it in. I saw somewhere else that it goes to the tank.
    It is NOT the wire for the shut off valves.
    I didnt look at the fuel guage sender but i recall that is a different color.
    Should that be going to the engine?
    20200714_132310.jpg
     
  6. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    Myself, I would get it running in the boat and then figure out what doesn't work.
     
  7. William Miller

    William Miller Member

    250
    Mar 16, 2007
    Darnestown, Maryland
    290 AJ
    Twin Mercruiser 300 hp Bravo III
    The earlier pictures was the back of the engine near the coil.
    These are the wires for the trim gauge sending unit.
    I have the older 2 wire puck.
    I dont think it could possibly be digital.

    I havent found that diagram yet. Its not on the one for the trim pump because it doesnt effect that.
    Those wires were on another harness anyway
     
  8. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    If you have a multiple choice it's not going to burn anything up to try them all.
     
  9. William Miller

    William Miller Member

    250
    Mar 16, 2007
    Darnestown, Maryland
    290 AJ
    Twin Mercruiser 300 hp Bravo III
    Update:
    Per the 555 manual.
    I have the 2 plug ecm with the round 10 pin connector and the rectangular "CAN" connector.
    The wire marked "analog" goes to the round 10 pin connector.
    The wire marked "digital" goes directly to a pin on the ecm.

    It is NOT a "digital" sending unit. Its the older type rehostat. But the voltage is read by the ecm and sent to smartcraft via the CAN.
    I think a few years after mine the changed to the 3 wire sending unit.

    I hope my explanation is correct and helps someone in the future!
    Tested yesterday as i finally installed the outdrives and adjusted the new trim limit switches and sending units.
     
  10. William Miller

    William Miller Member

    250
    Mar 16, 2007
    Darnestown, Maryland
    290 AJ
    Twin Mercruiser 300 hp Bravo III
    Update on the pink wire.
    I have pretty much confirmed that it gets connected to the engine harness where it changes color. This pink wire on the boat harness goes to the sending unit on the fuel tank. It feeds the ecm which sends the signal to smartcraft via CAN.

    When powering up the ignition yesterday for the first time, Smart craft told me that it had a fault.

    My only problem is the connector on the engine harness must be burried on the back of the engine where i cant see.
    My project tomarrow is to get mirrors and lights to find out where it is. Its a 3 pin connector but only one pin is used.

    Uhgggggg
     
  11. William Miller

    William Miller Member

    250
    Mar 16, 2007
    Darnestown, Maryland
    290 AJ
    Twin Mercruiser 300 hp Bravo III
    Pink wire done. Found behind the distributer.
    Engines running in boat.
    Fuel shutoff solonoids bypass position.
    The set of grey and black wires are supposed to be for that.

    F10 and M10 connectors.
     
  12. William Miller

    William Miller Member

    250
    Mar 16, 2007
    Darnestown, Maryland
    290 AJ
    Twin Mercruiser 300 hp Bravo III
    I REALLY NEED HELP WITH THIS!
    ANYONE?
    I cannot find anywhere to connect these.
    The engines are running with the solenoid fuel valves set on BYPASS

    I cannot find a connector near the fuel relay.
    The fuel pump is connected correctly at the Mercruiser harness.


    Here is a section of the wiring diagram.
    The part you see in red is what exits the boat harness with the CAN wire.




    Fuel Shutoff.jpg



    F11 and M11 connectors
    F10 & M10 connector for fuel shutoff.jpg

    Connectors and wires back to the splice: Splice Point A and B in the diagram.
    Fuel Shutoff wiring at engine.jpg



    Fuel Solenoid on top of tank:
    Grey and black wires from Splice point A&B are the power and ground to the solenoid valve that opens the fuel valve.
    solonoid.jpg
     
  13. William Miller

    William Miller Member

    250
    Mar 16, 2007
    Darnestown, Maryland
    290 AJ
    Twin Mercruiser 300 hp Bravo III
    Well.... The light bulb went off in my head.

    Maybe I disconnect the wire that currently goes to the fuel pump.
    Connect F10 to the fuel pump.
    Connect M 10 to the wire that fed the fuel pump.

    Can someone take a look at this and let me know what they think!
     

Share This Page

Show Sidebar