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    No fuel Pump

    Fuel Pump relay doesn't turn the pump on so I jumped 87 and 30 with a jumper
    Fuel is present at the rail
    Checked Crank Sensor Resistance - within spec
    Spark was checked with an timing gun -blinks so there must be spark right?
    Pulled a spark plug can't smell fuel.
    Pulled spark plug out and grounded sparks when cranking

    hmmm....
    checked the injectors today.
    Resistance at the coils are at 16.3 ohms within spec as per the Bently
    There is 12V at the injector when the engine cranks
    That should mean the DME is ok right?

    Did the following checks at the DME harness as per the Bentley

    -Voltage Supply at the control unit - ok
    -Fuel Pump relay control - ok
    -Fuel Injector control - ok on both banks
    -Main relay control -ok

    Checked Fuel Pressure at the rail with the fuel pump jumped.
    45 PSI with pump on


    40 PSI residual


    I also checked the terminals at the relay socket
    #30 and ground = battery voltage
    #86 and ground = battery voltage
    multi meter on #85 & #86 turn key to on = battery voltage
    multi meter on #85 & #86 turn key to crank = battery voltage
    Also checked voltage at the fuel pump - nothing with the relay, battery voltage when jumped.

    Continued to do some continuity checking
    DME #3 and Fuel Pump relay #85 = 0.9 ohms
    This tells me the wire between my DME and relay is ok - there is a connection

    This is a strange one, I remove the relay socket from the holder and inserted the tester into the rear of Fuel Pump Relay #85 = Ground when off; 12V When Key on
    I take the relay out and its ground again? What the fuck?
    This is why the pumps are not turning on, it sounds like a bad or disconnected ground

    So I continue with checking the DME's grounds
    DME #2,14,19,24 continuity to grounds = 0.8 ohms
    - meaning good grounds

    Check Power at DME
    #27 = 12V
    #18 = 12V
    Power is going to the DME

    Check CPS resistance again @ the DME #47 & 48 = 508 ohms (within spec)

    And check Main Relay DME #36 and main relay #85 = continuity 0.8 ohms

    What's wrong with my car?

    I also bought a new relay and plugged it in, still nothing.
    Swapped DME's for a known good one - still no luck

    The car runs when the fuel pump relay is jumped but doesn't when the relay is installed.

    Last thing does the 325i prime the pumps when you turn the key to start or does it just pump when cranking?

    #2
    Originally posted by Paradox View Post
    Last thing does the 325i prime the pumps when you turn the key to start or does it just pump when cranking?
    only pumps when cranking is detected
    1989 cirrisblau-metallic 325i

    Comment


      #3
      Correct, the DME only grounds pin 85 of the relay when it sees timing data from a rotating engine.
      The car makes it possible, but the driver makes it happen.
      Jim Levie, Huntsville, AL

      Comment


        #4
        Did you ever solve this mystery? Having a similar issue.
        "A BMW that needs nothing, has an owner that's not paying attention."


        Comment


          #5
          Crank sensor having the correct resistance does not necessarily mean it is good (ask me how I know). However if your getting spark I would think the cps is good.

          Comment


            #6
            Did you check to see if the injectors are pulsing? You should test the injectors with a noid light if you have not done so.
            90 325i DD/Track
            03 Durango 5.9


            Originally posted by e30mpg
            It is recommended to get new gasket but this is R3v and we just copper spray that shit......slap biotch on and tighten to tq.

            Comment

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