Boost Cut Problems very serious

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  • S2sedan
    S2Forum Enthusiast
    • Aug 2004
    • 189

    #1

    Boost Cut Problems very serious

    I`m having problmes since I did my RS2 mods. All mechanical mods wore made with no problems, but my eletronics are terrible.

    My car was a chipped ABY and had hard boost cuts some times, it came worst when I did the RS2 mods, so I tried to remap it. Chip tuners are terrible in Brazil ( Don´t say: Look after Mihnea, I tried real hard several times... no answer). Now my problems are:

    My are still running under 1.5 bar. I always cuts near 1.4, 1.5 bar . A real bad cut. I higher gears it cuts near 1.3, 1.4 on Wot.
    If I try to manage the boost on my foot, staying near 1.2, 1.3 I have no problem.

    I thought that ABY could run near 1.5 bar. Is there any flow difference when we use the RS2 turbo, so the engine cuts early 1.5 bar, or i have a big problem. I looked for a boost leak, and found nothing. my vaccum is near -0.6, -0.5 on idle.

    And it gots near -0.9.

    I already tried to disconnect my WG and my pressure is about 0.5

    DOES ANYONE HAVE AN IDEA WTF&%# IS GOING ON WITH THIS DAMN CAR ?????????????????????????
    S2 Limo sold !!!
    M5 E34 with some mods in the garage
    sorry, but much happeir now !
  • Mihnea
    S2Forum Extremist
    • Jul 2003
    • 1288
    • Home: Belgium Current: United Kingdom

    #2
    Bad chip.

    I know I have been terrible answering emails, but if you want a fix, let me know it.

    Mihnea
    '98 Silver Grey 2.7T S4, dual 2.75" turbo back exhaust with no cats, FMIC, BIG injectors, 10 Bar motorsport fuel pump, modded RS4 turbos, tubular exhaust manifolds, custom intakes, RS4 MAF, Bilstein PSS9, H&R ARBs, 19" BBS CH, custom remap, 511 BHP/505ft-lbs

    www.MRCTuning.com
    info@MRCTuning.com
    Workshop Directions

    Comment

    • Greg_S
      Administrator
      • Jul 2003
      • 12430
      • Country: United Kingdom

      #3
      sounds like you probably have a boost leak that needs to be rectified before you go any further.
      Greg

      S2Forum.com Administrator & Webmaster

      '93 Coupe with a few tweeks

      Comment

      • S2sedan
        S2Forum Enthusiast
        • Aug 2004
        • 189

        #4
        Mihnea, I really need help ASAP !!!
        .......

        About the leak, Once I had a Real big one, and the car never cuts, so why It cuts now ???
        S2 Limo sold !!!
        M5 E34 with some mods in the garage
        sorry, but much happeir now !

        Comment

        • Mihnea
          S2Forum Extremist
          • Jul 2003
          • 1288
          • Home: Belgium Current: United Kingdom

          #5
          S2Sedan: pressurize the intake to make sure there are no leaks at all. If there aren't and the problem is still there, email me again, I'll be at home today and tomorrow, then again at the end of the week, and I should be able to get back to you and do you a chipset.

          Cheers,

          Mihnea
          '98 Silver Grey 2.7T S4, dual 2.75" turbo back exhaust with no cats, FMIC, BIG injectors, 10 Bar motorsport fuel pump, modded RS4 turbos, tubular exhaust manifolds, custom intakes, RS4 MAF, Bilstein PSS9, H&R ARBs, 19" BBS CH, custom remap, 511 BHP/505ft-lbs

          www.MRCTuning.com
          info@MRCTuning.com
          Workshop Directions

          Comment

          • S2sedan
            S2Forum Enthusiast
            • Aug 2004
            • 189

            #6
            Ok, I will try to do that. Tell me one more thing, when the MAP cuts the boost it cuts like on ignition, like a overboost protection or it only drops the boost ?

            thank for your fast reply this time !


            You got an e-mail !!! ..
            S2 Limo sold !!!
            M5 E34 with some mods in the garage
            sorry, but much happeir now !

            Comment

            • Mihnea
              S2Forum Extremist
              • Jul 2003
              • 1288
              • Home: Belgium Current: United Kingdom

              #7
              Originally posted by S2sedan
              Ok, I will try to do that. Tell me one more thing, when the MAP cuts the boost it cuts like on ignition, like a overboost protection or it only drops the boost ?

              thank for your fast reply this time !


              You got an e-mail !!! ..
              There's 2 cuts available in the motronic M2.3.2: maximum MAF exceeded or maximum boost exceeded. MAF will cut the fuel pump (no more engine) for a second, then use less loss. boost will only cut boost and then start rising again...

              Mihnea
              '98 Silver Grey 2.7T S4, dual 2.75" turbo back exhaust with no cats, FMIC, BIG injectors, 10 Bar motorsport fuel pump, modded RS4 turbos, tubular exhaust manifolds, custom intakes, RS4 MAF, Bilstein PSS9, H&R ARBs, 19" BBS CH, custom remap, 511 BHP/505ft-lbs

              www.MRCTuning.com
              info@MRCTuning.com
              Workshop Directions

              Comment

              • S2sedan
                S2Forum Enthusiast
                • Aug 2004
                • 189

                #8
                after the cut, the car can´t get over 0.5 - 0.6 bar it cuts again, and all the time it tries to raise the boost again.

                cheers eduardo.
                S2 Limo sold !!!
                M5 E34 with some mods in the garage
                sorry, but much happeir now !

                Comment

                • Mihnea
                  S2Forum Extremist
                  • Jul 2003
                  • 1288
                  • Home: Belgium Current: United Kingdom

                  #9
                  MAF cutout then, it could be due to a leak, but not necessarily, a bad chip will do the same. If that's the case, a Unichip won't fix the problem, as it would have to hardwire the fuel pump relay so the ECU doesn't shut it, plus boost control would have to be manual, unless you can live with boost that goes up and down.

                  I don't know if you really want that, as if you hardwire the fuel pump relay, it won't shut itself in case of an accident, and you may get caught on fire...

                  Mihnea
                  '98 Silver Grey 2.7T S4, dual 2.75" turbo back exhaust with no cats, FMIC, BIG injectors, 10 Bar motorsport fuel pump, modded RS4 turbos, tubular exhaust manifolds, custom intakes, RS4 MAF, Bilstein PSS9, H&R ARBs, 19" BBS CH, custom remap, 511 BHP/505ft-lbs

                  www.MRCTuning.com
                  info@MRCTuning.com
                  Workshop Directions

                  Comment

                  • S2sedan
                    S2Forum Enthusiast
                    • Aug 2004
                    • 189

                    #10
                    Is it the same as overboost protection ???

                    eduardo
                    S2 Limo sold !!!
                    M5 E34 with some mods in the garage
                    sorry, but much happeir now !

                    Comment

                    • S2sedan
                      S2Forum Enthusiast
                      • Aug 2004
                      • 189

                      #11
                      Or a fault MAF, because it was not doing when the car came from the garage, i changed the WG Spring for the original one and one day suddenly my S2 start doing it !

                      MAF
                      Bad Chip
                      Boost Leak

                      ??????
                      S2 Limo sold !!!
                      M5 E34 with some mods in the garage
                      sorry, but much happeir now !

                      Comment

                      • quattroamm
                        S2Forum Addict
                        • Dec 2003
                        • 306
                        • Country: United Kingdom

                        #12
                        overboost

                        Originally posted by S2sedan
                        Or a fault MAF, because it was not doing when the car came from the garage, i changed the WG Spring for the original one and one day suddenly my S2 start doing it !

                        MAF
                        Bad Chip
                        Boost Leak

                        ??????
                        have you tried replacing solenoid valve (follow pipe from wastegate)
                        1991 90 quattro 20v sport 450 bhp
                        Rs2 engined ur quattro sold
                        11 golf tdi

                        Comment

                        • S2sedan
                          S2Forum Enthusiast
                          • Aug 2004
                          • 189

                          #13
                          I think If solenoid valve try to send more boost than it should, my gauge will show.
                          S2 Limo sold !!!
                          M5 E34 with some mods in the garage
                          sorry, but much happeir now !

                          Comment

                          • S2sedan
                            S2Forum Enthusiast
                            • Aug 2004
                            • 189

                            #14
                            I`m starting to think that i have a faulty MAF, my idle sometimes get strange, very slow to come down from 1100, difficult to start, and i`m getting really really low mileage with my tank. my multimeter is rich most part os the time.
                            Any idea ???
                            S2 Limo sold !!!
                            M5 E34 with some mods in the garage
                            sorry, but much happeir now !

                            Comment

                            • Erikb
                              S2Forum Maniac
                              • Jul 2004
                              • 648
                              • Country: Netherlands

                              #15
                              I also have the same problems. I cleaned my MAF with carb cleaner, and changed the lambdasonde. It has improved, especially the mileage. Still the idle is strange and after a cool down periode of approximate 2 hours it is hard to start.
                              Getting everything sorted out for my 5++ hp project

                              Comment

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