7A hesitation/flat spot

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  • Error404
    Super Moderator
    • Mar 2007
    • 19789
    • Country: United Kingdom

    #31
    RE the TPS it could be the indexing of the range against actual throttle opening, i.e the TPS is telling the ECU porkie pies.
    Panthero Coupé quattro 20vt
    Indigo ABY coupé
    Imola B6 S4 Avant

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    • stocious
      S2Forum Maniac
      • Jul 2012
      • 838
      • Country: Ireland

      #32
      What condition are the plug leads, you mentioned you were checking plugs/spark , could be they have broken down more aafter being disturbed
      1991 S2 3B Coupe, KW v1, solid sub frames, poly bushed, chipped, about 260 ish

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

        #33
        Yes and the weather has got damper, start it up in the dark and see if you can see any sparks. Look around the top of the coil and the single lead from coil to dizzy.

        S2 Coupe 3B Project


        Ur quattro restoration

        S2 Avant

        Boost is the new rock and roll!
        sigpic

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        • goodall
          S2Forum Maniac
          • Jul 2008
          • 810
          • Country: Northern Ireland

          #34
          Nice fresh morning today, started the car let her idle for 3 mins and took her out the road, first mile faultless across the rev range but started to give bother after that, stopped the engine disconnected the maf and started her went a mile up the road engine behaved just the same with the same flat spots and hessitation. So my assumption from this is the maf is bad and isnt couping with the underbonnet heat once the engine is warm

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

            #35
            Did you check for sparks in the dark?

            S2 Coupe 3B Project


            Ur quattro restoration

            S2 Avant

            Boost is the new rock and roll!
            sigpic

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            • Error404
              Super Moderator
              • Mar 2007
              • 19789
              • Country: United Kingdom

              #36
              I think I have a 7A MAF if you need one
              Panthero Coupé quattro 20vt
              Indigo ABY coupé
              Imola B6 S4 Avant

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              • goodall
                S2Forum Maniac
                • Jul 2008
                • 810
                • Country: Northern Ireland

                #37
                Nope I was out for few drinks last night so didnt get the chance but to night must get a go at doing it.

                How much for the MAF my spare didn't seem to fix the issue but it had the A suffix where as my car didn...

                Not sure just how much I want spend to get the 7A running right as have a AAN just sitting

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                • Error404
                  Super Moderator
                  • Mar 2007
                  • 19789
                  • Country: United Kingdom

                  #38
                  I'll check the p/n as i think it might be the A variant. You can have it for the cost of post mate if it helps, its no use to me but I didn't want to just bin it
                  Panthero Coupé quattro 20vt
                  Indigo ABY coupé
                  Imola B6 S4 Avant

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                  • goodall
                    S2Forum Maniac
                    • Jul 2008
                    • 810
                    • Country: Northern Ireland

                    #39
                    Cheers, don't have a TPS too? Ill PM about the MAF

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                    • goodall
                      S2Forum Maniac
                      • Jul 2008
                      • 810
                      • Country: Northern Ireland

                      #40
                      Checked the plug leads, some gentle sparks around the cap from the leads and odd spark against the cam cover/manifold but not sure if so bad should be concerned?

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                      • Kieron20V
                        S2Forum Extremist
                        • Mar 2008
                        • 1505
                        • Home: England Current: United Kingdom

                        #41
                        If it runs the same with the maf disconnected I wouldn't say the maf is the problem. With it disconnected it should run ok but down on power as it's just on assumed failsafe values.

                        If you've got sparks jumping from the leads to various bits of the engine then I'd say your leads are knackered and you found your problem.

                        Sent from my HTC One X+ using Tapatalk 2
                        1994 URS4 Avant RS2+

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                        • goodall
                          S2Forum Maniac
                          • Jul 2008
                          • 810
                          • Country: Northern Ireland

                          #42
                          I have a set of silicone leads off a KV that I might try see if can fit down the head recess then... Failing that alittle oil along the origionals might help I guess at least to see a improvement

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

                            #43
                            Originally posted by goodall
                            Checked the plug leads, some gentle sparks around the cap from the leads and odd spark against the cam cover/manifold but not sure if so bad should be concerned?
                            You should have no visible sparks at all. If the leads are breaking down as it seems is the case, then WD40 sprayed on might give you a few minutes of clean running..

                            S2 Coupe 3B Project


                            Ur quattro restoration

                            S2 Avant

                            Boost is the new rock and roll!
                            sigpic

                            Comment

                            • goodall
                              S2Forum Maniac
                              • Jul 2008
                              • 810
                              • Country: Northern Ireland

                              #44
                              Changed the leads this morning, still same problem. Will check tonight see these silicone leads are leaking at all too... I'll try and get some to hold the camera so can get a video later to post as itll help me see the exact instances too

                              Its annoying me as I took the car along a section of road that I absolutely love this morning and its wet so perfect for quattro but with the engine kicking like this I can't get as fast as Id like and even if I could she would likely throw me of the road with the sharpness of the misfire

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                              • goodall
                                S2Forum Maniac
                                • Jul 2008
                                • 810
                                • Country: Northern Ireland

                                #45
                                Tested the fuel pump this evening, got 175ml in 10 seconds, so 1050cc/min. This was done by directing the outlet the fuel pressure regulator into a Pyrex jug and activating the pump manually. However the injector in on a 7A are rated at 120cc in 20 seconds so 360cc/min or 1800cc/min total but I doubt the duty cycle is high enough to mean my pumps the issue and Id expect the pump to cause the car to sort of cap in power not come and go in surges...

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