how can this happen

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  • paullap
    Member
    • Dec 2016
    • 64

    how can this happen

    Hi I am still on this Citroen C3 1.4 petrol KFV engine

    Live data shows the injector pulse width all over the place
    injector 1 65 M/Seconds fluctuating
    Injector 2 about 120 M/s fluctuating
    Injector 3 208 M/Seconds fixed and does not move
    Injector 4 60 M/ seconds fluctuating


    I have scoped each injector and they are perfect between 3 and 5 M/seconds
    all looks great. So what is going on, Is it getting corrupt through the BCM?.

    Has anyone ever seen this before?


    Paul
  • Witsend
    Banned
    • Nov 2012
    • 2942

    #2
    I don't know why , Is ...
    Does another scantool of another brand or at least a different update level display the same live injector data that you read off your Verus?
    Engine running smooth without any missfire on #3?
    Relative compression look good?
    Spark look good on 3?
    Fuel pressure look good without leakdown?
    Injector resistance and flow balance test look good across the board?
    Fuel trims look good and no vacuum leak at the intake runner on #3?
    Last edited by Witsend; 03-01-2018, 02:47 PM.

    Comment

    • paullap
      Member
      • Dec 2016
      • 64

      #3
      Hi Thanks for the reply.

      I have used 3 scan tools, all the same

      Engine dose not seem to have a misfire

      relative compression good

      Fuel pressure good without breakdown

      (Injector resistance and flow balance test look good across the board)
      not sure how to do this one, I have scoped all 4 injectors and they look good

      o2 sensor switching nice 0.2/0.8

      I was checking to power and earths going to the ecu and one of the earths I am not very happy with it has noise on going up to abut 0.7 volts and I have seen the spike. I will try to upload the files so you can take a look if you have time please.

      Sorry I can find how to post the files, If you can let me know how to do it they are shop stream files, If if pm me your email I can do it easy.


      Thanks


      Paul
      Attached Files

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      • Witsend
        Banned
        • Nov 2012
        • 2942

        #4
        I can't see the SSC files because I don't have SSC on my PC. Are all 4 injectors when ground switched, is the voltage of all 4 injectors on the ground side wires actually getting pulled to ground (the 0V line)?

        Comment

        • paullap
          Member
          • Dec 2016
          • 64

          #5
          Hi yes all 4 injectors are pulling to ground and they are all going up to about 40 volts good pinsel humps. I could email pics if you want, My concern at the moment is the noise on the earth wire, the other 2 earth wires are perfect.

          something is corrupting the live data and i am suspecting the BCM



          On the earth wire with the noise , if I disconnect the throttle body it disappears,

          something is corrupting the live data and i am suspecting the BCM

          I am not sure if it should do this


          Paul

          Comment

          • Witsend
            Banned
            • Nov 2012
            • 2942

            #6
            After it is running , could you disconnect the BCM from the data bus to see if it that affects your live data?

            Comment

            • Witsend
              Banned
              • Nov 2012
              • 2942

              #7
              Look at the wiring diagram The PCM may actually have control of both the power and ground wires of the throttle body control and KOEO you can hear alot of electronic noise emanating from an electronic throttle bodies which I think might be normal.

              Comment

              • paullap
                Member
                • Dec 2016
                • 64

                #8
                Hi The throttle body goes to the ECM, I would like to show you the image I got from testing the earth's one has got a lot of interference, and I have one shot with a spike of negative and positive of only about 1 volt, But from watching you tube videos, that is not acceptable,

                Comment

                • paullap
                  Member
                  • Dec 2016
                  • 64

                  #9
                  earth wire noise

                  Comment

                  • paullap
                    Member
                    • Dec 2016
                    • 64

                    #10
                    earth spike



                    I found this when earth testing with the scope. it looks like a spike to me, You cant see it all but it goes plus and minus about a volt. does any know anything about earth testing using the scope and finding these problems.


                    Paul

                    Comment

                    • paullap
                      Member
                      • Dec 2016
                      • 64

                      #11
                      update

                      Ok , I decided to take a look at another C3 today same engine but running perfect, I looked at the live data, and the readings are exactly the same. cylinder 3 injector fixed on 208 M/Seconds. so I don't know why it would show this, It cant be the scanner as I have used 2 other scanners and they both show the same.

                      Comment

                      • Mechatronics Engineer
                        Junior Member
                        • Jul 2017
                        • 9

                        #12
                        You don't actually say what if any are the driving symptoms, but referring to the earth fault, try and put a new earth in place and see what happens, could be a fault switched earth, so bypass it and see what happens!

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