I am beaten

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  • DEREKCO
    S2Forum Addict
    • Feb 2009
    • 435
    • Country: United Kingdom

    #1

    I am beaten

    Ok guys car is still running poorly (see my post ) i ran a live data scan engine not running ignition on i got a temp reading (engine cold) of minus 45 c is that right , that indicates an open circuit ,so i unplugged the temp sensor creating an open circuit reading still minus 45 i then got a jumper wire and shorted the plug out still minus 45 , the temp sensor resistance is 3200 ohms . Anyone make sense of this , please reply S2 has now been off the road now 4 weeks ( look at previous posts to see what i have changed or renewed .Derek
  • Nuvo
    S2Forum Possessed
    • Nov 2003
    • 3825

    #2
    Maybe a corroded or damaged plug pins or break in the sensor wiring?

    Comment

    • newsh
      S2Forum Obsessed
      • Aug 2003
      • 16226
      • Country: United Kingdom

      #3
      Hi mate
      Pull the boot off the back of the temp sensor plug, the one on the back of the head, on mine the wires were broken inside the boot where they'd got twisted up. I cut a couple of inches off and soldered the pins back on and all good.

      S2 Coupe 3B Project


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      • DEREKCO
        S2Forum Addict
        • Feb 2009
        • 435
        • Country: United Kingdom

        #4
        I am beaten

        Ok guys the wiring is ok i cut the conduit back no bare wires ,i ran a continuity test on the feed wire and the earth wire back to the ECU no broken wires ,i also ran a resistance check on both cables from the plug back to the ECU 0.01 ohms the sensor is brand new OEM resistance is 3200 ohms , live data with engine cold ignition on - 45 c with plug connected to sensor , that should not be its not -45 c in Consett. Temperature should be ambient ,today 10 deg.c .If i disconnect the sensor then short the plug out that should max out the ECU ,it would appear the ECU cannot adapt or locate the closed circuit ,it should show a positive deg temp ,it shows a minus reading connected or disconnected , sorry if this does not make sense but that is what I am finding. Any ideas

        Comment

        • twoqu
          S2Forum Possessed
          • Sep 2003
          • 3103

          #5
          Is the inlet air tempearture also at a minus figure?
          If so I think its a red herring and something do do with how VCDS reads the sensors without the engine running.

          Comment

          • DEREKCO
            S2Forum Addict
            • Feb 2009
            • 435
            • Country: United Kingdom

            #6
            I am beaten

            Si do i ,i believe it's a base reading .

            Comment

            • prj
              S2Forum Zealot
              • Mar 2010
              • 6308
              • Country: Estonia

              #7
              Live data always shows -49C when engine is not running, ADC is only polled for those sensors once it's turned over.

              The only ADC that's continuously polled is the TPS one.
              http://tuner.ee - http://www.facebook.com/tuner.ee

              Comment

              • twoqu
                S2Forum Possessed
                • Sep 2003
                • 3103

                #8
                At least we can put the G62 to rest!
                I wonder if this is a Lambda issue. I know you have changed it but it doesen't rule out either a signal or heating issue!
                As the Lambda has to be electrically heated to get to working temp, when the car starts, it is in open loop not closed loop I understand, which means it ignores the lambda signal. After a certain period of time it then switches to closed loop utilising the lambda signal. So that may explain the consistant time related behaviour.
                I am tempted to say just remove the signal wire from the lambda and see what happens.
                Or perhaps you could leave it connected and observe either Field 8 in the 10 measuring blocks or Group1 Field 3 which is the Lambda. When the symptoms occur see what the readings change to.
                The workshop manual states that Field 8 should be between 123-133 AFTER 1 1/2 minutes. If it remains at a fixed value of 128 then there is an issue. These numbers correlate to the Lambda values 0.96-1.04 in the Group 1 Field 3.
                So if I am right the 128 value basically represents Lambda 1 which is what the ecu is trying to achieve. This also corresponds to a sensor voltage of @0.45V.
                Basically once the ecu switches to closed loop then the figures should fluctuate. I am not sure how the ecu decides to switch but if the signal is not what the ecu expects after the switch then that might be a factor. Its difficult to seperate the causes from the symptoms so we need to rule other things out.

                Comment

                • twoqu
                  S2Forum Possessed
                  • Sep 2003
                  • 3103

                  #9
                  It does seem that 90 secs is the time it takes for a Lambda to get heated to working temperature so that makes a bit of sense.

                  Comment

                  • Bowie69
                    S2Forum Fiend
                    • Nov 2013
                    • 2675
                    • Country: England

                    #10
                    Even a lambda pagged either way will only alter fuelling a very small amount, maybe up to say 10% (I don't know how these ECUs handle it entirely), it is just a fuel trim, and often actually not used at idle because it produces a wandering/erratic idle.

                    So, I, personally, would be looking elsewhere.

                    Oh, just checking the other thread, the lambda has been changed.

                    Comment

                    • DEREKCO
                      S2Forum Addict
                      • Feb 2009
                      • 435
                      • Country: United Kingdom

                      #11
                      I am beaten

                      Sorry guys am getting depressed and getting nowhere fast with this xxxxx car , it starts first time perfect , after about 1-2 mins it starts to hunt try and throttle it ,it dies ,leave it and it ticks over then stalls , it starts immediately and goes through the same scenario , time and time again, i have boost checked and vacuum tested till i am sick ,i have tested and changed every xxxxx thing on it and not getting anywhere ,guys have a think , its running rich ,what cause a car to run rich ? G62 , pressure regulator stuck, ECU not recognising temp signal , i don't know

                      Comment

                      • mike74
                        S2Forum Maniac
                        • Apr 2014
                        • 615
                        • Country: Scotland

                        #12
                        You tried cleaning the maf?

                        Comment

                        • DEREKCO
                          S2Forum Addict
                          • Feb 2009
                          • 435
                          • Country: United Kingdom

                          #13
                          I am beaten

                          Hello yes MAF has been cleaned but i have a new one on order also looking at it sensor as well

                          Comment

                          • Bowie69
                            S2Forum Fiend
                            • Nov 2013
                            • 2675
                            • Country: England

                            #14
                            Just unplugging the MAF is likely to stick it in limp-home mode, which would mean it would at least still run -it is one way to test.

                            One thing to also try, bring the revs up to say 2K, and hold it there from first starting, does it still die/die more quickly/last longer?

                            Comment

                            • mike74
                              S2Forum Maniac
                              • Apr 2014
                              • 615
                              • Country: Scotland

                              #15
                              Do you still have the original coil packs and associated cover? If not have to tested the quality of the spark you're getting?
                              Also, try running the car without the fuel cap installed in case something's amiss there...

                              Comment

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