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740T in tank pump

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  • 740T in tank pump

    Is there an easy way to know if this pump is working?

  • #2
    If you crack the hatch under the rear decking, and expose the fuel tank bung.. you can hear/ feel it running when you put key in the on position( not start) .. it only primes for a few seconds.. so have someone else turn the key on while you monitor..
    hope this helps.. good luck!


    • #3
      If the car is down on power you could have a bad pump. There are two fuel pumps one in the tank and one under car about where the front seat is. Just look directly under and you'll see a bracket with fuel pump and filter.
      as stated, listen in the rear of car or remove gas cap and listen for a BZZZZZ lasts maybe a second.

      Just because it's "working" that doesn't necessarily mean it's doing what it's supposed to be doing. The tank pump is a pre-pump to supply the main pump and together they must put out not only the correct fuel pressure but the correct fuel volume for the engines needs.
      Last edited by 05V70RGT; 05-27-2020, 03:44 AM.


      • #4
        Well? Howzit? Is the pump working?


        • #5
          Well this is perplexing. The pump runs on the bench, with fluid of course, but I am not detecting anything in the tank.
          The car is a 1991 T and all I read, view, talks about a Ground wire. I saw a picture of a harness with the ground wire for a 1990 740 but I cannot find that wire on my harness.
          There appears to be a ground wire in the harness that goes through the plug, did they change in 1991?
          I am going to check for continuity through the plug next.


          • #6
            Have you checked the fuel pump fuse?