Fuel Injector not firing???

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  • Tchao
    Wrencher
    • Apr 2007
    • 223
    #1

    Fuel Injector not firing???

    Hey guys, I recently swapped a M50nv into a 91 318is. The fuel injectors are not firing. The M50 came out a 86' e30 that was running when removed. Went over a the x20-c101 connection and everything was the same except for 3 wires. And those 3 wires were just cut in the harness and was not used in the 86'.

    Heres what I know so far:

    The x20-c101 was re-done as per the diagram on this site. (6 times checked for mistakes)

    The crank position and cam sync are both plugged in properly.

    If I manually ground the injectors to fire, and jump the fuel pump, it starts and runs what the brief fuel allows (2secs or so)

    The fuel pump does not run when cranking or running, needs jumping, and jumped it for the trouble shooting.

    Ignition is fine, or so it seems, as it did idle until the fuel runs out.

    All grounds are on the engine and added extra grounds on the head to chassis as part of problem solving.

    Car is getting 12v from fresh battery plus another car. So voltage isnt an issue. Measures 12's during cranking.



    Some background info:
    While dropping the motor in, I did stress and pinch the injector harness against the firewall pretty bad. But all the injectors are connected and pins connected (as I was able to jump fire them from the harness)


    Is there a harness connection I dont know about near the back firewall that could of gotten messed up, causing the ECU not to fire the fuel injectors?



    TIA,
    San
    Tags: None
    • Tchao
      Wrencher
      • Apr 2007
      • 223
      #2
      Is there a signal wire that could of been wrong/missing causing only the injectors not to fire?

      Also does motronic do batch fire for the 24v also?

        Comment

        • mazur
          Mod Crazy
          • Jan 2006
          • 731
          #3
          It's sequential.

          Anyways I would make sure that the car does have spark during cranking. That would help diagnosis if we knew that both spark and fuel are missing or not.

            Comment

            • Tchao
              Wrencher
              • Apr 2007
              • 223
              #4
              It does. Because when I manually add fuel it will fire right up and run for a sec or two.

                Comment

                • DEV0 E30
                  R3V OG
                  • Oct 2004
                  • 8816
                  #5
                  Get this sorted yet San?

                  I haven't seen the new car.

                  Do you have the injectors grounded? Are the grounds old and frayed?

                  I'm not sure if you could have messed up the wires enough stressing them but I guess it's possible, I would double check them.
                  Project: Touring | Project: Unknown | Phoenix, Arizona Events Thread

                    Comment

                    • jrdeamicis
                      E30 Modder
                      • Nov 2008
                      • 956
                      #6
                      Manually add fuel as in?

                      In the rail?
                      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

                        Comment

                        • mazur
                          Mod Crazy
                          • Jan 2006
                          • 731
                          #7
                          Problem fixed. After removing the some of the main relays the first time around to troubleshoot, he mistakingly put them back in the wrong spots, doh!

                            Comment

                            • Tchao
                              Wrencher
                              • Apr 2007
                              • 223
                              #8
                              It's solved! :)

                              Manual as in jump the pump and ground the injectors.

                              Turned out to be a hand full of things gone wrong. Still do t really know why it sparked but no fuel. But I don't care now :D

                                Comment

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