Wgfv disconnected but still get 1.5 bar boost

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

    #1

    Wgfv disconnected but still get 1.5 bar boost

    So been laid up all week with chicken pox and sat pondering about the car and its niggles etc

    Still not getting 2 bar boost as I should, been thinking fuel pump related as that's one of the last things I've yet to upgrade.

    Anyway, went out tonight and thought I'd disconnect the wgfv to see what mechanical boost I was getting, expecting 0.4 bar it still boosts to the same @ 1.5 bar.

    Only time I've heard of this I'd when the wgfv has been bypassed with a crappy bleed valve !

    Anyone had this before ?
  • AndyP
    S2Forum Zealot
    • Feb 2004
    • 6049
    • Country: England

    #2
    Take the wastegate cap off and see what spring you have in there.
    sigpic
    1991 Audi S2 3B - 2.5 Stroker engine
    1997 A6 2.5TDi quattro avant - C4
    1976 RD250E / 350LC cafe racer

    Comment

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

      #3
      Standard mate I've recently seen it

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      • Acidburn
        S2Forum Obsessed
        • Jun 2007
        • 13459
        • Country: United Kingdom

        #4
        could be a leak around the wgfv, what are the hoses like?

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        • AndyP
          S2Forum Zealot
          • Feb 2004
          • 6049
          • Country: England

          #5
          Originally posted by andyg plym
          Standard mate I've recently seen it
          Did you check the diaphram too?
          sigpic
          1991 Audi S2 3B - 2.5 Stroker engine
          1997 A6 2.5TDi quattro avant - C4
          1976 RD250E / 350LC cafe racer

          Comment

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

            #6
            Yes all new vacuum pipes boost leak tested a while ago (only to approx 1 bar as we found a leak elsewhere !)

            Diaphragm on inspection seems fine, the wg was off when I pulled the engine a few months ago and all appeared to be working, freely moving etc

            The cars done approx 90k

            Comment

            • driftin jo
              S2Forum Fiend
              • Sep 2007
              • 2222
              • Country: United Kingdom

              #7
              When the WGFV's fail they normally fail open so you get mechanical boost, they have been know in rare circumstances to fail closed or partly closed, which could explain what is happening.

              The only way to be sure is try another WGFV, is the someone near you you can borrow one from to test.

              Comment

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

                #8
                His is probably just plugged in the wrong way round.

                Try running direct hose from turbo to wastegate to confirm.
                http://tuner.ee - http://www.facebook.com/tuner.ee

                Comment

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

                  #9
                  @prj who is exactly is "his" ?

                  If you are referring to me I can assure its plumbed in correctly, after 9 years and 10 s2's you sort of remember

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

                    #10
                    Well, just run a direct line to the wastegate to check...
                    If indeed everything is correct and nothing is leaking then the n75 should be stuck in some intermediate position.
                    http://tuner.ee - http://www.facebook.com/tuner.ee

                    Comment

                    • AndyP
                      S2Forum Zealot
                      • Feb 2004
                      • 6049
                      • Country: England

                      #11
                      Try putting 12v to the WGFV terminals or use VCDS output test if you have it. If it works you'll hear it clicking, if it's seized you won't.
                      sigpic
                      1991 Audi S2 3B - 2.5 Stroker engine
                      1997 A6 2.5TDi quattro avant - C4
                      1976 RD250E / 350LC cafe racer

                      Comment

                      • Rusty
                        Super Moderator
                        • Jun 2004
                        • 18953
                        • Country: United Kingdom

                        #12
                        Originally posted by prj
                        Well, just run a direct line to the wastegate to check...
                        Cheers'en, AndyC
                        1994 ABY Coupe - Projekt Alpinweiss

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