Announcement

Collapse
No announcement yet.

Boost issue - Logic check

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Boost issue - Logic check

    Hi Everyone,

    I need to some input from others to see if my logic makes any sense.

    I have a 1995 urS6 AAN and I've recently asked my mech to repair a boost leak for me on a connector that kept on jumping off. After I got it back I felt that there's little to no boost and from a basic visual I couldn't see any obvious issues on the pressure side of the plumbing. The display value (absolute) barely reaches 1.3 so effectively I have almost no boost at all...

    I don't have a boost leak tester yet (still need to make one) but I'm fairly confident that the issue isn't on the pressure side.

    Here's why I think that;

    When I drive it I can barely hear the turbo (relative to before). I use to be able to actually hear it clear as day. That coupled to the fact that no pressure is registering on the display makes me think that the turbo doesn't spool...a boost leak would've made a noise at least. Currently the car feels NA and sounds NA.

    The AF doesn't appear to be rich either and I'm thinking that if the turbo doesn't spool much and the ECU only fuels for what the MAF measures (effectively NA pressure levels) fueling wouldn't be off by much.

    Thus my logic takes me to the wastegate...I'm thinking the wastegate stays open (I doubt it a mechanical issue such as dirt or grime) because of the n75 perhaps? Or the line going from the n75 to the wastegate that is suppose to keep it closed...

    I haven't checked the n75 plumbing arrangement yet but hopefully the mech didn't mess with that.

    I can swop out the n75 if need be but I'd like to understand the symptoms for future knowledge.

    Any input/ideas on my logic here?

    Appreciated any advice.

    Regards
    Corrie






  • #2
    I think if it was boost leak it would spool up then violently cut out feels horrible

    Comment


    • #3
      Take a look at this post: https://www.s2forum.com/forum/techni...ne#post2125291

      Comment


      • #4
        I’d check that the N75 is connected up correctly before you start chasing other options

        Comment


        • #5
          With age and wear the wastegate might not be able to hold boost giving the feeling of NA not letting the turbo spool, you can remove the WG cap and see if there is to much play in the shaft sideways.

          Comment


          • #6
            Thank you for the input. I'm checking the wastegate and n75 this weekend. I have noticed that the pipe that goes to the wastegate appears not to fit perfectly tight but I'll replace that one in any case also just to be sure.

            Comment


            • #7
              Any fault codes??

              Comment


              • #8
                Tried scanning tonight but it seems my 2x2 is problematic. Going to pick up a new one on Saturday. Will post findings after a scan.

                Sent from my SM-S908E using Tapatalk

                Comment


                • #9
                  Check the plug on the N75, it might not be fully plugged in. Carefully pull back the rubber boot and look for broken wires.
                  Check the same with MAF plug.
                  Check for leaks in the vac line from inlet manifold to ECU, best to do this with a Mightyvac or cycle pump with football inflator from the IM end.
                  Last edited by newsh; 20 August 2022, 09:01.

                  S2 Coupe 3B Project


                  Ur quattro restoration

                  S2 Avant

                  Boost is the new rock and roll!
                  sigpic

                  Comment

                  Working...
                  X