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fuel pump relay and dme issues

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    #1

    fuel pump relay and dme issues

    Here's the story...My daughter was just driving along going 60 and the 325es just quits running. I tow it home and run some tests. Here is what I have done so far.

    changed fuse 11 with different fuse just to be sure that was not the issue.

    Jumpered the fuel pumps at the relay and both pumps turn on. The bentley says to test for voltage across relay terminals 85 & 86 while cranking and if not present then the main relay has a problem.

    tested main relay and not getting any voltage between relay terminal 30 and ground.

    Tested junction block for 12v on firewall and it does have voltage.

    Tested ECU harness to try and get injectors to fire and nothing.

    Looked at fusable link in trunk and it looks good as nothing is melted.

    Tested for voltage supply to ECU from terminals 18 and 35 to ground and no voltage is present...of course the main relay was not in place at the time!

    What could be the problem?
    The difference between porcupines and BMWs is that porcupines have the pricks on the outside!
    Tags: None
    #2
    Any spark?

    If not, and injectors aren't firing, isn't that usually the Crank Position Sensor?
    1987 E30 325is
    1999 E46 323i
    RIP 1994 E32 740iL
    oo=[][]=oo

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      #3
      Have not delved into the spark realm yet as I figured the fact that the main relay is not functioning as it should due to it not testing properly that I was on the right track. I can't figure why the ECU harness is also not testing properly too. The car cranks fine, but I don't hear the fuel pumps working when I turn on the key!
      The difference between porcupines and BMWs is that porcupines have the pricks on the outside!

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        #4
        Do you have power on all points (both wires) in the firewall? The small one feeds the ecu

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          #5
          I checked the junction block at the fire wall and removed and cleaned all the connections and tested each wire at its connection to that block and all have voltage.
          The difference between porcupines and BMWs is that porcupines have the pricks on the outside!

          Comment

            #6
            update - I don't know what I did but the car is now running. I was testing the ECU harness and was able to verify everything but power to the unit as that was still dead. I was getting frustrated so I just started wiggling wires in the main harness at the firewall while trying to test for power still to the ECU harness. I went to the other side of the engine bay to wiggle wires at the main relay and inserted a spare relay and all of a sudden I had voltage in on both pins.

            I went back and connected the ECU harness and the car started and ran like a charm. I then turned off the ignition and put the other relay in just to be sure and it did not start. Put good relay back in and the car started again.

            The thing that puzzles me is that I put that same relay in when the car was stalled before I towed it home and it did not start. I think wiggling the wires did something that made the relay work like maybe there was a short and it ruined the other relay so when I wiggled the wires the short went away and that allowed the good relay to work properly.

            I guess we will see if this happens again...if it does, at least I will know to wiggle some wires before towing the thing!!
            The difference between porcupines and BMWs is that porcupines have the pricks on the outside!

            Comment

              #7
              Seems like my issue

              Which wiring did you shake as this sounds like the EXACT same problem my 1987 325es is having... see this post:

              http://www.r3vlimited.com/board/showthread.php?t=159856


              any help is useful....this issue has been bugging me since early december.


              -Alex

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