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1991 318ic start problem

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    1991 318ic start problem

    I searched posts and might have missed a solution to this. I'm short on time. I'm working on a 1991 318i convert.

    No power to the fuel pump. Pulled pump in tank-it works.

    There's very little juice to the pump connector 4.86 volts as key is turned on, then drops to 2 or less volts a second or 2 later. When cranking the voltage stays that low.

    I have no idea where things like crank sensors are and don't know where the fuel relay and main relays are located.

    The car was parked , then a little while later had to be pushed into the garage. I got the it to start and idle for about 8 minutes at one point (it smelled real gasy) then it died and hasn't restarted. Please respond with full part names and locations as abbreviations are unknown to me. I'll post updates as soon as I have them.

    Thanks.
    sigpic



    To bad the bonnet opens the wrong way

    IIII

    #2
    Update

    Reinstalled fuel pump, with new filter screeen (about $10.00 local national chain autoparts store). Checked for 2nd pump (main fuel pump), I only found the one thats in the tank. With voltage meter wasn't getting any power to fuel pump, fuse 11 (which was good) wasn't getting any power. Finally located the three relays (against the firewall, behind a long plastic cover that snapped off). White relay (assuming this is main relay) towards passenger side, then two orange relays. The middle relay was the fuel pump relay, not sure what the other orange relay operates (it's closet to you when looking from the drivers side. Removed the whole harness to reach wires under relays (pinched black tab on side towards firewall, pulled that tab towards the relay and pulled the relay and harness up). Then I was able to get to wires easier to test for voltage. Red wire (power in) had 12 + volts. With voltage meter setting on windshield, on top of wiper, was able to watch the voltage from the other pins when the key was turned. No voltage was present on pin #30 at any point. Then removed relay and placed low gauge wire from pin #87 to pin #30. Fuel pump came to life.

    Started car.

    Bad relay, right. Here's the odd part. As the engine was running, put relay back in, after I removed the jumper wire. Expected the engine to run out of gas and stall.

    It just kept idling.

    The only thing I can think is the relay contacts were "welded" closed and by putting it in while the engine was running somehow the voltage surge to the relay popped it open or possibly vise versa. I don't know but it works.
    :bow:
    The car started several times thereafter and ran fine. I don't trust it, so I will be replacing the relays, of course.
    sigpic



    To bad the bonnet opens the wrong way

    IIII

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