VEMS cold start issue

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

    #16
    It's more intelligent than that, it will iterate between the two numbers to get an enrichment figure.

    150 seems a lot of extra fuel at 80C to me.

    Start followed by stall is as you say, ASE, fiddle with this, but you really only get one try per day when properly cold.

    Comment

    • Tom_
      S2Forum Extremist
      • Oct 2007
      • 1301
      • Country: Czech Republic

      #17
      Originally posted by prj
      Also, this might be painfully obvious, but do make sure that VEMS is showing the correct coolant temperature and the sensor is not knackered.
      As no amount of tuning the cold weather bins will save you if the sensor is telling the ECU the engine is at 40 degrees, when actually it's freezing outside.

      Btw, in case it's useful for someone, stock 2.2T Motronic cranking enrichment, which I've needed to tweak only extremely rarely:
      Code:
      -33C 1800%
      -20C 838%
      0C 363%
      10C 238%
      40C 125%
      94C 100%
      prj Could those values be recalculated to bigger injector values? As those values are from the stock 2.2 engine with stock injectors (around 300cc maybe?, so with 980cc injectors those values will be 3x smaller than with stock injectors?
      Audi Coupe Quattro 2.3 20V

      Comment

      • le mans
        S2Forum Enthusiast
        • Nov 2013
        • 165
        • Country: New Zealand

        #18
        This is the stock warmup map:
        Screenshot 2025-01-07 223207.png

        Comment

        • Tom_
          S2Forum Extremist
          • Oct 2007
          • 1301
          • Country: Czech Republic

          #19
          What axis is what? Also those values are % of how much fuel is added against the normal fuel?
          Audi Coupe Quattro 2.3 20V

          Comment

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

            #20
            Those values alone are useless to you, because you don't know how it works. Also this is warmup enrichment and not cranking fuel.
            Read my post that I made back in 2013, which has the cranking values fully calculated... If you want to calculate the warmup factor, then this is an additive, not a multiplicative map. 128 means add 100% of the fuel. So you could say that 128 = 200% and 256 = 300%

            Axis is blatantly obvious.

            Also your question about injectors makes zero sense. These are fuel enrichment values, they have nothing to do with injectors whatsoever, as the injectors are linearized elsewhere. Both in Motronic and in VEMS.

            I really recommend doing some learning and reading instead of playing excel calculator with your engine. At the moment you don't understand the basics of how the engine and the engine management works, which is evidenced by some of the absurd questions. You will never learn this from forums ever, reading literature and having a lot of patience is required to get anywhere.
            http://tuner.ee - http://www.facebook.com/tuner.ee

            Comment

            • varia
              S2Forum Maniac
              • Mar 2009
              • 821
              • Current: United States

              #21
              Originally posted by prj
              Those values alone are useless to you, because you don't know how it works. Also this is warmup enrichment and not cranking fuel.
              Read my post that I made back in 2013, which has the cranking values fully calculated... If you want to calculate the warmup factor, then this is an additive, not a multiplicative map. 128 means add 100% of the fuel. So you could say that 128 = 200% and 256 = 300%

              Axis is blatantly obvious.

              Also your question about injectors makes zero sense. These are fuel enrichment values, they have nothing to do with injectors whatsoever, as the injectors are linearized elsewhere. Both in Motronic and in VEMS.

              I really recommend doing some learning and reading instead of playing excel calculator with your engine. At the moment you don't understand the basics of how the engine and the engine management works, which is evidenced by some of the absurd questions. You will never learn this from forums ever, reading literature and having a lot of patience is required to get anywhere.
              Good to see you back !!!!
              sigpic

              Comment

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

                #22
                Originally posted by varia

                Good to see you back !!!!
                Hey, thanks... Would not say I'm back, but I have some subscriptions still active on a few threads.
                http://tuner.ee - http://www.facebook.com/tuner.ee

                Comment

                • booested4door
                  S2Forum Enthusiast
                  • Feb 2015
                  • 120
                  • Country: United States

                  #23
                  Originally posted by prj
                  Those values alone are useless to you, because you don't know how it works. Also this is warmup enrichment and not cranking fuel.
                  Read my post that I made back in 2013, which has the cranking values fully calculated... If you want to calculate the warmup factor, then this is an additive, not a multiplicative map. 128 means add 100% of the fuel. So you could say that 128 = 200% and 256 = 300%

                  Axis is blatantly obvious.

                  Also your question about injectors makes zero sense. These are fuel enrichment values, they have nothing to do with injectors whatsoever, as the injectors are linearized elsewhere. Both in Motronic and in VEMS.

                  I really recommend doing some learning and reading instead of playing excel calculator with your engine. At the moment you don't understand the basics of how the engine and the engine management works, which is evidenced by some of the absurd questions. You will never learn this from forums ever, reading literature and having a lot of patience is required to get anywhere.
                  what are some of these books and avenues to learn this stuff? I need to learn this also. Please and thank you

                  Comment

                  • le mans
                    S2Forum Enthusiast
                    • Nov 2013
                    • 165
                    • Country: New Zealand

                    #24
                    One option here: Online Car Modification Courses | BUILD.TUNE.DRIVE
                    They also upload some info free to youtube.

                    Comment

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