ADU-Engine wont idle properly (Misfires, dont run on all cylinders)

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  • vism
    S2Forum Fanatic
    • Jun 2007
    • 97
    • Current: Norway

    #1

    ADU-Engine wont idle properly (Misfires, dont run on all cylinders)

    Hi everyone

    I have a problem with a ADU (RS2)Engine. The whole engine has been rebuilt, with custom JE-Pistons and new rods.

    The problem is that when idle (900-2000RPM) it wont fire on all 5 cylinders (it sounds as it doesnt fire on all cyl. But maybe it does.... not comfirmed)

    Doesnt sound good and is probably getting way to much fuel. Misfires alot. about -0.1 - 0 Bar vaacum on idle.

    From 2000RPM and up however, everything is running fine, and it runs as it should.

    The only fault i can see is from Vag-Com:

    "00515 - Camshaft Position (Hall) Sensor (G40)
    01-00 - Signal Shorted to Plus
    00515 - Camshaft Position (Hall) Sensor (G40)
    30-00 - Open or Short to Plus"


    The hall sensor has been changed and checked. Also, the timing has been checked multiple times and looks correct.. The head is from a 3B engine with a new hall sensor fitted in front. This also looks correctly placed compared to a ABY head.

    Any ideas? All suggestions welcome..
    Last edited by vism; 2 June 2008, 21:33.
    '91 Audi S2 Coupe
    '85 Audi 80
  • andyg plym
    S2Forum Freak
    • Nov 2006
    • 4646
    • Country: England

    #2
    you say rebuilt? does that include ALL coilpacks? i know even a worn coilpack will still idle fine and will show up under load, but you never know

    Comment

    • andyg plym
      S2Forum Freak
      • Nov 2006
      • 4646
      • Country: England

      #3
      whoops!!! misread!! after 2000rpm its all fine? problem at idle?

      Comment

      • vism
        S2Forum Fanatic
        • Jun 2007
        • 97
        • Current: Norway

        #4
        Yep, thats correct. The strange part is that the problem never occours over 2000RPM, if the coil pack is the problem, wouldnt it be the other way round? (Fail on higher RPM?)
        '91 Audi S2 Coupe
        '85 Audi 80

        Comment

        • andyg plym
          S2Forum Freak
          • Nov 2006
          • 4646
          • Country: England

          #5
          Originally posted by vism
          Yep, thats correct. The strange part is that the problem never occours over 2000RPM, if the coil pack is the problem, wouldnt it be the other way round? (Fail on higher RPM?)
          yes you are right.....had the same thing myself recently

          Comment

          • denniselbows
            S2Forum Maniac
            • Mar 2007
            • 740
            • Country: United Kingdom

            #6
            is the throttle position sensor positioned correctly? i had problems with that which cause similare symptoms as you discribe i would thought it would bring up a fault code though.clear the fault codes and recheck to see if anything else comes up
            never set your expectations to high that way you are never disapointed

            Comment

            • WabTheKing
              S2Forum Fiend
              • May 2004
              • 2567
              • Country: United Kingdom

              #7
              agree with above sounds like tps isnt set right

              Comment

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

                #8
                Originally posted by vism
                I have a problem with a ADU (RS2)Engine. The whole engine has been rebuilt, with custom JE-Pistons and new rods.

                The head is from a 3B engine with a new hall sensor fitted in front. This also looks correctly placed compared to a ABY head.
                I'm confused. Just what is it about this engine that makes it an RS2 ADU? The crank bearings?
                RS2'd 93 UrS4 5 spd sedan
                94 UrS4 V8 6 spd manual avant

                Comment

                • Bram
                  S2Forum Fiend
                  • Aug 2006
                  • 2582
                  • Country: Netherlands

                  #9
                  Are you sure you have set the cam timing correctly? If I remember correctly the HALL sensor reads the signal until a certain RPM and above that it does not use the signal anymore from the HALL. But I am not 100% sure, so if somebody can verify this?

                  Comment

                  • madpugger
                    S2Forum Extremist
                    • Sep 2007
                    • 1901
                    • Country: Scotland

                    #10
                    I think it is after 4000 rpm and only on WOT that it stops using the hall.

                    Le Mans 2012
                    Nurburgring 700
                    1995 S2 Avant

                    Comment

                    • oleab
                      S2Forum Hobbyist
                      • Nov 2007
                      • 10
                      • Country: Norway

                      #11
                      Originally posted by UrS4boy
                      I'm confused. Just what is it about this engine that makes it an RS2 ADU? The crank bearings?
                      It is the motronic ECU, the injectors, the cams, the maf...
                      Just a modified ADU with other words.

                      Comment

                      • vism
                        S2Forum Fanatic
                        • Jun 2007
                        • 97
                        • Current: Norway

                        #12
                        Originally posted by UrS4boy
                        I'm confused. Just what is it about this engine that makes it an RS2 ADU? The crank bearings?
                        Block, wiring, turbo, intake, manifold? It is a ADU-engine with a 3B head, SCAT rods and JE-pistons.
                        Last edited by vism; 3 June 2008, 12:04.
                        '91 Audi S2 Coupe
                        '85 Audi 80

                        Comment

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