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    Dme problem?

    Hi, I've been having a problem with my '87 e where it turns over with no spark till I unplug the Dme and plug it back in. Afterwards it starts right up. The problem is intermittent but happens more than not. Any ideas? Thanks

    #2
    A flaky main relay is a possibility. The DME may not be powering up. The DME controls the main relay and grounds the coil when it is presented with a START signal from the ignition switch. I'd replace the main relay and check for START and switched power from the relay at the DME (open the cover to expose the back side of the connector). If I saw the START signal, unswitched power to the DME, and no ground to the relay coil I'd replace the DME. In a like manner if the main relay was closing and power from the relay is present I'd replace the DME.

    Or you could skip the trouble shooting and replace the main relay and DME.
    The car makes it possible, but the driver makes it happen.
    Jim Levie, Huntsville, AL

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      #3
      Originally posted by jlevie View Post
      A flaky main relay is a possibility. The DME may not be powering up. The DME controls the main relay and grounds the coil when it is presented with a START signal from the ignition switch. I'd replace the main relay and check for START and switched power from the relay at the DME (open the cover to expose the back side of the connector). If I saw the START signal, unswitched power to the DME, and no ground to the relay coil I'd replace the DME. In a like manner if the main relay was closing and power from the relay is present I'd replace the DME.

      Or you could skip the trouble shooting and replace the main relay and DME.
      ^ I need to check this on my eta too. I replaced the dme, main relay, replaced the sensors, coils, wires, and checked the pickup at the flywheel. Still no sparks. There is one thing that I can not find is the black/yellow wire in ignition switch according to the wire diagram.
      sigpic
      327is
      325es
      325es
      318is
      Fiesta ST
      E46 M3

      Comment


        #4
        With what you have replaced, the first check would be to see if unswitched power, START, and switched power from the main relay are present at the DME when ignition is switched on and that power is present at the coil positive. You should also verify connectivity from the DME to the timing sensors and to the coil ground.
        The car makes it possible, but the driver makes it happen.
        Jim Levie, Huntsville, AL

        Comment


          #5
          I have completely checked the START power from main relay and power is present at the DME and grounds. still no start. connectivity from DME to Sensors is checked and good. Ignition switch check on RUN and Start is good.
          I did hear relay clicks when cranking and have fuel pressure. However when I pop the FPR out, there seems pressure has been built up from all the cranking. now the seal is broken and I can't put it back in.
          Dont know if the FPR is bad or not, but I don't think it would affect the sparks, does it? Or non working injectors will send a signal to the DME not to send sparks? I am totally frustrated now.
          Last edited by dsphil; 08-13-2012, 02:14 PM.
          sigpic
          327is
          325es
          325es
          318is
          Fiesta ST
          E46 M3

          Comment

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