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    Runs, won't stay running.

    The motor hasn't really ran in eight or so years. I changed the oil and drained / filled up the fuel.

    Now, I'm pretty sure it's some sort of fuel delivery issue. If I jump the terminals at the fuel pump relay for a little bit until I hear pressure, then I can turn the car over and it starts just fine and runs for a minute until the pressure gives out.

    I bought a brand new fuel pump relay, but the engine still just starves for fuel unless I prime it manually with the jumpers, then it runs for a minute and slowly dies.

    It appears that the alternator isn't working or barely charging, as the light stays on while the car idles. It idles pretty evenly and strongly, and will run every time as long as I prime it first.

    So, what's the culprit here? Maybe the rest of the system isn't getting enough juice off just the battery alone? It's a new battery but obviously it's slowly running down on juice, I had it jumped to make sure it was giving out enough.

    Anybody have any experience with this? '87 325is btw.
    Last edited by Komzorz; 08-08-2011, 07:35 PM. Reason: forgot to put my model and year.
    '87 325is - Schwarz/Schwarz

    #2
    Well just chase down your Fuel pump wire into your c101 connector and verify your ECU is giving the body power for the fuel pump relay. That will decide the rest of your troubleshooting.
    Past Car : E30 S50 6 Speed 5 Lug 3.73
    Current : Z3 S50 OBD2 (Smog Legal) 6 Speed BBS RN Dual Ear Diff
    ___________________________________________
    BNB Designs
    Engine Swaps, Fabrication, Innovation, General Repair
    Richmond CA
    Julian 848-248-8029

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      #3
      Okay, I didn't test at the c101 but I did test at the pump relay wires directly as per the bentley manual.

      The fuel pump circuit is indeed getting power all the time at socket 30.

      Terminals 85 and 86 get approximately battery voltage when the starter is turned. Basically, no faults found.

      Now, the bentley says if those tests pass and the fuel pump will only run with the jumper connected (which it does), then the relay is faulty.

      Well, it's not because it's brand new and it's the right one.

      ??? I jumpered the relay and started the car just for kicks, and it ran like a peach till I turned it off. Alternator appears to be totally dead, and so all this stuff is really draining my battery.

      Soo, any ideas? I'm moving soon and it's really gonna suck if I have to tow this car to my new place.
      '87 325is - Schwarz/Schwarz

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        #4
        Car stayed running after I swapped the alternator, btw. Figured I'd add some closure to the thread.
        '87 325is - Schwarz/Schwarz

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