Fuel priming procedure?

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  • jake5
    Member
    • Sep 2014
    • 83

    #1

    Fuel priming procedure?

    I recently did the axle carrier, and trailing arm bushings.
    While in there, I dropped the tank and had it boiled (mountains of crap in there, and old fuel pump, a filter and a bolt) ,of course I did the fuel filter at the same time
    Got the whole mess back together. I put 6 gallons of fuel in the tank and have been cranking forever. The fuel system was completely dry from the tank fix. Fuel pump has power when cranking, as it should. Anyone have experience with this? I am getting worried about this much cranking on the starter and battery.
    ...before you go there. I searched.


    Sent from my iPad using Tapatalk
  • roguetoaster
    R3V OG
    • Jan 2012
    • 7733

    #2
    Well, you can't rule out a blockage (pump/filter/injectors), a crossed line, or a dead pump, so check where the fuel has traveled so far as a first step.

    If you find fuel at near the rail it's possible that you could have an air pocket (but you shouldn't), and then you would have to open the system forward of that to clear it.

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    • AndrewBird
      The Mad Scientist
      • Oct 2003
      • 11892

      #3
      The pump will turn on briefly when you first turn on the key. So just turn the key on and off several times to "prime" the system. Then crank.

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      • nando
        Moderator
        • Nov 2003
        • 34827

        #4
        Originally posted by AndrewBird
        The pump will turn on briefly when you first turn on the key. So just turn the key on and off several times to "prime" the system. Then crank.
        only on the M42. On M20, M10, and S14 cars, the fuel pump only runs when the engine is cranking.
        Build thread

        Bimmerlabs

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        • dnguyen1963
          R3VLimited
          • Nov 2011
          • 2648

          #5
          Use an external 12V power to turn the pump on.

          Comment

          • AndrewBird
            The Mad Scientist
            • Oct 2003
            • 11892

            #6
            Originally posted by nando
            only on the M42. On M20, M10, and S14 cars, the fuel pump only runs when the engine is cranking.
            Interesting. Didn't know that.

            Comment

            • IceWhite
              E30 Modder
              • Jan 2015
              • 945

              #7
              Originally posted by nando
              only on the M42. On M20, M10, and S14 cars, the fuel pump only runs when the engine is cranking.
              CPS, correct?
              1990 325i
              2004 330i Individual 6-speed
              sigpic


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              • e30davie
                E30 Mastermind
                • Apr 2016
                • 1788

                #8
                If everything is hooked up like it should be and everything is bone dry (except the tank) the fuel will take like 1-3 seconds to get from the pump to the engine. If after 5 seconds you have nothing you have bigger problems.

                Comment

                • e30davie
                  E30 Mastermind
                  • Apr 2016
                  • 1788

                  #9
                  Originally posted by nando
                  only on the M42. On M20, M10, and S14 cars, the fuel pump only runs when the engine is cranking.
                  My L-Jetronic 323i e30 m20 has a priming circut built into the fuel pump relay. I cant find reference to the e30 one quickly, but here is info in relation to the e28. Don't think the Americans got the 323i e30s though. L-jet is a fairly archaic system but kinda cool they included this timed relay.

                  Last edited by e30davie; 01-15-2019, 02:39 PM.

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                  • wodcutr
                    R3VLimited
                    • Apr 2009
                    • 2193

                    #10
                    Just jumper the fuel pump relay at pins 30 and 87. The fuel pump will run as long as you want!
                    The difference between porcupines and BMWs is that porcupines have the pricks on the outside!

                    Comment

                    • jake5
                      Member
                      • Sep 2014
                      • 83

                      #11
                      Wow. Thanks guys.
                      Definitatly taking more than 3 seconds. I disconnected fuel line and checked for plugs. Blew low pressure air through and was clear. So I pulled the pump and connected directly to the battery. It just clicks. I cant hear anything running. It was working fine when it came out. So I am thinking bad pump right? Must have some how went bad when carefully removing and replacing?

                      Sent from my SM-G950U using Tapatalk

                      Comment

                      • jake5
                        Member
                        • Sep 2014
                        • 83

                        #12
                        Originally posted by jake5
                        Wow. Thanks guys.
                        Definitatly taking more than 3 seconds. I disconnected fuel line and checked for plugs. Blew low pressure air through and was clear. So I pulled the pump and connected directly to the battery. It just clicks. I cant hear anything running. It was working fine when it came out. So I am thinking bad pump right? Must have some how went bad when carefully removing and replacing?

                        Sent from my SM-G950U using Tapatalk
                        Oh yah. Checked power when cranking. Good. Then after checking lines, I disconnected before filter ti see if it would pump. Nothing. Then removed pump and hooked to battery as above. So yah bad pump right?

                        Sent from my SM-G950U using Tapatalk

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                        • jake5
                          Member
                          • Sep 2014
                          • 83

                          #13
                          Originally posted by jake5
                          Oh yah. Checked power when cranking. Good. Then after checking lines, I disconnected before filter ti see if it would pump. Nothing. Then removed pump and hooked to battery as above. So yah bad pump right?

                          Sent from my SM-G950U using Tapatalk
                          Oops. Wire backwards. It kinda whirs softly. Still though, didn't pump so gatta be the pump. Crap nuggets!

                          Sent from my SM-G950U using Tapatalk

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                          • Kershaw
                            R3V OG
                            • Feb 2010
                            • 11822

                            #14
                            I bought a new pump assembly off Amazon for $50 for my rallycross car 2 years ago. It's been holding up great. Something like this https://www.amazon.com/Electric-1614...dp/B07L8T81F6/

                            You can also find just the pump itself for $25.
                            AWD > RWD

                            Comment

                            • digger
                              R3V Elite
                              • Nov 2005
                              • 5899

                              #15
                              What could possibly go wrong.
                              89 E30 325is Lachs Silber - currently M20B31, M20B33 in the works, stroked to the hilt...

                              new build thread http://www.r3vlimited.com/board/showthread.php?t=317505

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