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93 m50tu cranks but won't start

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    93 m50tu cranks but won't start

    Little history, stock 93 525i 5speed, drove fine few days ago until I parked it. It sat for a few days and then wouldn't fire in the morning but just cranked.

    Things I've done so far:

    -tried jumping it in case battery was low, no difference.
    -it has gas

    -checked each ignition coil per bentley, has voltage and measures ok.
    -measured each ignition boot, about 2.2k
    -checked for spark, it's got spark when cranking

    -connected fuel pressure gauge at the front of the fuel rail, over 50psi when cranking.
    -pulled each spark plug, look ok and smell of fuel.

    -replaced all 3 relays and checked the fuel pump fuse just in case.

    - disconnected MAF , tried to start, no difference.

    - measured crank position sensor, measures about 493 ohm (bentley says 540 +/- 10% so this is probably ok).

    Cranks and crank and cranks, but won't start.

    Any tips?

    It's 93, so no EWS i don't believe...
    Mtech1 v8 build thread - https://www.r3vlimited.com/board/sho...d.php?t=413205



    OEM v8 manual chip or dme - https://www.r3vlimited.com/board/sho....php?p=4938827

    #2
    Pulled the back seat cover, checked the fuses there with dmm okay. Checked for voltage before/after what looked like inline fuse on the battery cable, okay as well.

    Pulled the injector harness cover, connected my DMM at the injector plug to check for voltage while cranking, voltage is there but not 12volt...more like 6 volts if that....?
    Mtech1 v8 build thread - https://www.r3vlimited.com/board/sho...d.php?t=413205



    OEM v8 manual chip or dme - https://www.r3vlimited.com/board/sho....php?p=4938827

    Comment


      #3
      Problem solved. Replaced DME.
      Mtech1 v8 build thread - https://www.r3vlimited.com/board/sho...d.php?t=413205



      OEM v8 manual chip or dme - https://www.r3vlimited.com/board/sho....php?p=4938827

      Comment


        #4
        Macgyver!!!
        sigpic

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