Engine running at last but issues....

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  • 20Vcqdriver
    S2Forum Maniac
    • Jun 2007
    • 829
    • Country: United Kingdom

    #1

    Engine running at last but issues....

    After 6 months I have now got my beast fired up and running. However there are issues I need help with. The car ticks over perfectly and opening the throttle gently is no issue, but quick opening of the throttle has the engine almost stalling, quick shut off of the throttle returns the the engine to perfect tickover without problem. This is done whilst the car is on the drive, not had the car on the road yet. Is this something that will clear after a good road run as this is the first start up after install? Also still have the old fuel in the tank from 6 months ago, will this affect things?! All help appreciated.
    Attached Files
    1986 Coupe q - 2281cc 3B, chargecooler, 2.75" exh & downpipe, ported head, water injection, CGR box, modified MD357 turbo, 440cc injectors, high power coil.
    2004 A4 2.5TDi convertible, re-mapped to 180bhp
    2011 A5 sportback 3TDi-Backbox delete, remap
  • Mark Halligan
    S2Forum Fiend
    • Jul 2003
    • 2001
    • Country: England

    #2
    Try giving it a drive (to the nearest petrol station), and let the ECU re-learn its mixture values and see how it goes from there on?

    Edit: nice engine bay
    Mark - Modded

    Comment

    • 20Vcqdriver
      S2Forum Maniac
      • Jun 2007
      • 829
      • Country: United Kingdom

      #3
      Thanks, it will not be easy to drive as it is and have no MOT or tax at present which doesn't help. Will try a trip out late tonight though.
      1986 Coupe q - 2281cc 3B, chargecooler, 2.75" exh & downpipe, ported head, water injection, CGR box, modified MD357 turbo, 440cc injectors, high power coil.
      2004 A4 2.5TDi convertible, re-mapped to 180bhp
      2011 A5 sportback 3TDi-Backbox delete, remap

      Comment

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

        #4
        Originally posted by 20Vcqdriver
        The car ticks over perfectly and opening the throttle gently is no issue, but quick opening of the throttle has the engine almost stalling, quick shut off of the throttle returns the the engine to perfect tickover without problem.
        Sounds like either the Mass Air Flow (MAF) meter or the throttle position sensor (TPS) are either sick or the connections to them are in need of cleaning. I suggest that at the very least you disconnect each one and clean the contacts (using something from the local electronics supply store) and then reconnecting them.

        If that doesn't work, I would see if you can borrow a known to be good MAF and TPS and seeing if that is the cure.
        RS2'd 93 UrS4 5 spd sedan
        94 UrS4 V8 6 spd manual avant

        Comment

        • 20Vcqdriver
          S2Forum Maniac
          • Jun 2007
          • 829
          • Country: United Kingdom

          #5
          help

          Have taken it round the block and it will not have any sudden throttle changes or half load. If sitting on the drive at 2000rpm you can feel the boost building in the concertina hose after the intercooler, but the engine sounds uneven, splutters, misses and after 30 secs starts running very rich with black haze out of the exhaust. Knock throttle shut and it instantly ticks over perfectly and the black haze dissapears.
          Think I need an expert and so intend on getting to Tim Cooper of Renn-Tech ASAP. Hope it is something simple!?
          1986 Coupe q - 2281cc 3B, chargecooler, 2.75" exh & downpipe, ported head, water injection, CGR box, modified MD357 turbo, 440cc injectors, high power coil.
          2004 A4 2.5TDi convertible, re-mapped to 180bhp
          2011 A5 sportback 3TDi-Backbox delete, remap

          Comment

          • Heat Seeking Missile
            S2Forum Maniac
            • Jul 2007
            • 658
            • Home: United Kingdom Current: Wales

            #6
            I have a working MAF and not too far from you if thats any help. It isn't perfect but did work ok.

            Mark
            '93 Brilliant Blue Audi S2 Avant - Broken again.
            '98 Tahiti Blue Rover 216SE Coupe
            '96 Arktiksilber Metallic BMW 525td (E34)
            '01 Dark Green Jeep Grand Cherokee 3.1LTD
            '97 Polar White Vauxhall Vectra 2.0Di LS
            '96 Alpine White Peugeot 306 XLDt

            Comment

            • stiglet
              S2Forum Extremist
              • Aug 2007
              • 1264
              • Country: United Kingdom

              #7
              Do 3B's have hall senders??

              If this was a 7A i would say hall sender for sure.

              Comment

              • Azman
                S2Forum Possessed
                • Sep 2005
                • 3205
                • Country: United Kingdom

                #8
                Nope other than on the dizzy. Would suggest that there is quite a boost leak somewhere. Mine did what you are describing when it blew a hose of the turbo. CHeck all the boost lines and vaccum lines matey then give it another whirl. Also check the timming marks are spot on, not an easy job I know and it means taking the front off again. Other thing would be most def the maf (but it would run better tahn you are desribing) and the TPS.
                My guess is boost leak.
                Dark Grey Avant
                RS2 FARB
                Powerflex Front wishbone bushes
                Alloy Subframe Bushes

                Comment

                • S2central.net
                  Retired OG Mod
                  • Jul 2003
                  • 16590
                  • Country: Northern Ireland

                  #9
                  DOuble check timing and for air leaks before spending any mo money...

                  Checked all the ECU fuses and ground straps ?

                  TPS or MAF are candidates for sure - see if you can borrow spares.
                  Paul Nugent
                  Webmaster http://S2central.net
                  Administrator http://S2forum.com

                  1994 S2 Coupe ABY - aka Project Lazarus
                  2001 A6 allroad 2.5TDi - family tank
                  2003 S4 Avant 4.2 V8 - daily burble

                  Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

                  There are only 10 kinds of people that understand binary - those that do, and those that don't

                  Comment

                  • 20Vcqdriver
                    S2Forum Maniac
                    • Jun 2007
                    • 829
                    • Country: United Kingdom

                    #10
                    Originally posted by Heat Seeking Missile
                    I have a working MAF and not too far from you if thats any help. It isn't perfect but did work ok.

                    Mark
                    Might be worth trying. But must be something I have done as this engine was running perfectly in the S2 before it was transplanted into mine. Thanks for help so far, let you know how I get on.
                    1986 Coupe q - 2281cc 3B, chargecooler, 2.75" exh & downpipe, ported head, water injection, CGR box, modified MD357 turbo, 440cc injectors, high power coil.
                    2004 A4 2.5TDi convertible, re-mapped to 180bhp
                    2011 A5 sportback 3TDi-Backbox delete, remap

                    Comment

                    • pixsaudisex2
                      S2Forum Possessed
                      • Sep 2004
                      • 3110

                      #11
                      Well done on getting all of this in there.. i would aso be tempted to check for leaks with boost pipes as they cause problems very close to what you are discribing.

                      Comment

                      • Heat Seeking Missile
                        S2Forum Maniac
                        • Jul 2007
                        • 658
                        • Home: United Kingdom Current: Wales

                        #12
                        Originally posted by 20Vcqdriver
                        Might be worth trying. But must be something I have done as this engine was running perfectly in the S2 before it was transplanted into mine. Thanks for help so far, let you know how I get on.
                        Drop me a PM when you want to borrow it and we'll arrange something

                        Mark
                        '93 Brilliant Blue Audi S2 Avant - Broken again.
                        '98 Tahiti Blue Rover 216SE Coupe
                        '96 Arktiksilber Metallic BMW 525td (E34)
                        '01 Dark Green Jeep Grand Cherokee 3.1LTD
                        '97 Polar White Vauxhall Vectra 2.0Di LS
                        '96 Alpine White Peugeot 306 XLDt

                        Comment

                        • martinjs
                          S2Forum Possessed
                          • Jul 2003
                          • 3205
                          • Country: England

                          #13
                          Try it with the MAF unplugged.

                          Comment

                          • 20Vcqdriver
                            S2Forum Maniac
                            • Jun 2007
                            • 829
                            • Country: United Kingdom

                            #14
                            half sorted

                            Thanks everyone and especially Mark "heat seeking missile" who provided the MAF to replace my duff one. By the time the MAF was changed I had double checked all the plumbing and wiring. Only issue now is that it does not feel much quicker than my old 7A engine and am thinking it may still be in limp mode or something or does it just need to be driven for a bit. Cheers.
                            1986 Coupe q - 2281cc 3B, chargecooler, 2.75" exh & downpipe, ported head, water injection, CGR box, modified MD357 turbo, 440cc injectors, high power coil.
                            2004 A4 2.5TDi convertible, re-mapped to 180bhp
                            2011 A5 sportback 3TDi-Backbox delete, remap

                            Comment

                            • Heat Seeking Missile
                              S2Forum Maniac
                              • Jul 2007
                              • 658
                              • Home: United Kingdom Current: Wales

                              #15
                              Glad to have been of some help. I dont know how your ECU was installed or even which one you're running but maybe its still saved the original fault from the ropey MAF sensor and just needs re-setting. I'm merely guessing now I'm afraid.

                              Mark
                              '93 Brilliant Blue Audi S2 Avant - Broken again.
                              '98 Tahiti Blue Rover 216SE Coupe
                              '96 Arktiksilber Metallic BMW 525td (E34)
                              '01 Dark Green Jeep Grand Cherokee 3.1LTD
                              '97 Polar White Vauxhall Vectra 2.0Di LS
                              '96 Alpine White Peugeot 306 XLDt

                              Comment

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