S6 timing

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  • twoqu
    S2Forum Possessed
    • Sep 2003
    • 3103

    #571
    The ecu repair is interesting as it means its a born again virgin or the nice Garage didn't actually bother opening it up!
    Even if it was damaged by repairing it, doesen't explain why it behaves the same more or less on different ecus.
    Asuuming its the same temp sensor we have been therefore and at the time it seemed to have worked. Then again if the ecu sees a plausible signal and its checks out in VCDS we have to assume it ok now.

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    • HMS-S6
      S2Forum Extremist
      • Jan 2010
      • 1164
      • Home: United Kingdom Current: England

      #572
      Personally I think it was charged for and not repaired as when I got to it, there were no marks on it at all.
      Yes, on VCDS the temp reading is exactly as you'd expect.

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      • twoqu
        S2Forum Possessed
        • Sep 2003
        • 3103

        #573
        Originally posted by HMS-S6
        Wouldn't this throw the ignition timing out at idle too? Mine is text book!

        Plus, through ALL this, my boost figures have always been good!
        Again I think the idle is a bit high if it was at 880rpm. I thought it should be 830rpm when hot and a bit more with the aircon boost on. Obviously it fluctuates and I seem to recall that VCDS shows different values of the same parameter in different measurement blocks. Again just an observation based on what I have been shown!

        We could do with an expanation of how the car apparently does not suck in enough air yet produces enough boost yet is as flat as a witches tit in the mid range!

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        • HMS-S6
          S2Forum Extremist
          • Jan 2010
          • 1164
          • Home: United Kingdom Current: England

          #574
          Still stinks of unmetered air but I've been disproving that since day 1.

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          • twoqu
            S2Forum Possessed
            • Sep 2003
            • 3103

            #575
            I would give the car a good charge over the New Year!
            Do you get the aircon boost at idle? Should be able to hear it or measure it! Be intersted to see what the idle is when hot and whether it increases with the aircon on. It should effect the ign timing as well I think. Not that this is necessarily a problem but who knows!

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            • twoqu
              S2Forum Possessed
              • Sep 2003
              • 3103

              #576
              If you get really bored you can X ref the atmospheric pressure sensor against the boost gauge in VCDS! Then again I don't think thats the most accurate sensor either and only effects boost pressure I believe.

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

                #577
                It could still be to do with a sensor reading wrongly, either the MAF or the Lambda. I know that both of these have been replaced and the pins in the MAF connector have been replaced too. I think I'd be looking at and cleaning very carefully the connectors for the lambda sensor and the ECU connector, ideally pulling the female pins and cleaning in between the mating contacts with some worn out 2000 grit wet and dry and good quality contact cleaner like Caig De-Oxit.

                S2 Coupe 3B Project


                Ur quattro restoration

                S2 Avant

                Boost is the new rock and roll!
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                • HMS-S6
                  S2Forum Extremist
                  • Jan 2010
                  • 1164
                  • Home: United Kingdom Current: England

                  #578
                  Originally posted by newsh
                  It could still be to do with a sensor reading wrongly, either the MAF or the Lambda. I know that both of these have been replaced and the pins in the MAF connector have been replaced too. I think I'd be looking at and cleaning very carefully the connectors for the lambda sensor and the ECU connector, ideally pulling the female pins and cleaning in between the mating contacts with some worn out 2000 grit wet and dry and good quality contact cleaner like Caig De-Oxit.
                  The lambda isn't used at all at WOT on a stock ecu.
                  I've checked a few times now, the continuity from ECU plug to the MAF pins which all come up with zero resistance. You're right though unmetered/incorrectly metered air is exactly how the car FEELS even. Plus, the figure at idle is text book. This is why o could really really do with a *control* car reading before heading down the wrong path blindly again.

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                  • twoqu
                    S2Forum Possessed
                    • Sep 2003
                    • 3103

                    #579
                    Going back to the idle. It seems the factory tolerance is quoted as 770-830rpm. Above and below these figures are faults needing investigation.
                    It also seem that there is a direct relationship between the measuring blocks 2 and 3, the idle speed and the engine load. The idle specification is 77-83 (X10). We know the load is a calulation based on rpm. The specified load range is 20-26.
                    So in effect each increment of the load equates to an increase in idle speed of 10 rpm, where 20 = 770rpm through to 26 = 830rpm. With the aircon on there should be an idle speed boost so both values should be in excess of the higher specified figures.
                    Therefore if the idle is truely 880rpm then the load figure should be higher than 26. Or looking at it another way if there is a descrepancy between the load figure and the idle speed it might again be suggesting an air leak. For example if the load is at 26 (830rpm) and the idle is 880rpm then that suggests unmetered air.
                    Of course I could be oversimplifying it! I await being shot down.
                    Last edited by twoqu; 30 December 2014, 22:02.

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                    • HMS-S6
                      S2Forum Extremist
                      • Jan 2010
                      • 1164
                      • Home: United Kingdom Current: England

                      #580
                      Maybe pop the MAF in the hose from IC to Throttle Body. That way, any leak would be on the BOOST side do unmeteres air at WOT would not be possible as everything then is under pressure. No vacuum.

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                      • HMS-S6
                        S2Forum Extremist
                        • Jan 2010
                        • 1164
                        • Home: United Kingdom Current: England

                        #581
                        In VCDS my nber 3 in group 000 stops rising at 255 despite the other channels showing true RPM. Is this normal?

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                        • UrS4boy
                          S2Forum Obsessed
                          • Feb 2006
                          • 11859
                          • Country: Canada

                          #582
                          Originally posted by HMS-S6
                          Maybe pop the MAF in the hose from IC to Throttle Body. That way, any leak would be on the BOOST side do unmeteres air at WOT would not be possible as everything then is under pressure. No vacuum.
                          I am quite sure that you can't just arbitrarily move the MAF from an atmospheric pressure, cold air temperature location to a pressurized hot air location and expect that everything will be wonderful without at least some remapping of the ECU.
                          RS2'd 93 UrS4 5 spd sedan
                          94 UrS4 V8 6 spd manual avant

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                          • HMS-S6
                            S2Forum Extremist
                            • Jan 2010
                            • 1164
                            • Home: United Kingdom Current: England

                            #583
                            Originally posted by UrS4boy
                            I am quite sure that you can't just arbitrarily move the MAF from an atmospheric pressure, cold air temperature location to a pressurized hot air location and expect that everything will be wonderful without at least some remapping of the ECU.
                            I did think that too but I do have a spare everything to at least try it. I've been searching for what full load should be expected to be via Google so I can compare mine but all I've come up with is 1.8t engines. Although an entirely different setup. ALL load readings I found at WOT were 180-190% in group 003. Mine is 110%.
                            Like I said, I'm struggling defining where to go with the car without readings from a car that runs correctly. Think I may just have to bite the bullet and buy another car to read.

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                            • twoqu
                              S2Forum Possessed
                              • Sep 2003
                              • 3103

                              #584
                              Originally posted by HMS-S6
                              In VCDS my nber 3 in group 000 stops rising at 255 despite the other channels showing true RPM. Is this normal?
                              Ignore me! Wrong group!
                              Last edited by twoqu; 30 December 2014, 20:32.

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

                                #585
                                Originally posted by HMS-S6
                                The lambda isn't used at all at WOT on a stock ecu.
                                I've checked a few times now, the continuity from ECU plug to the MAF pins which all come up with zero resistance. You're right though unmetered/incorrectly metered air is exactly how the car FEELS even. Plus, the figure at idle is text book. This is why o could really really do with a *control* car reading before heading down the wrong path blindly again.
                                But have you cleaned the ECU connector?

                                S2 Coupe 3B Project


                                Ur quattro restoration

                                S2 Avant

                                Boost is the new rock and roll!
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