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2002 1.8T Boost

jayorme Aug 30, 2011

  1. jayorme

    jayorme Member

    Hiya Guys,

    Owned my 2002 Audi A4 1.8T Sport since April. The car is in excellent condition and used every day.. Car runs great and is nippy enough but I am 100% sure I am getting no boost. Just seems like a NA car (I've owned two standard 1.8Ts Golfs in the past)

    I've replaced the MAF and DV but there is no difference.

    Reading up on Forums I am now looking at Cleaning the Throttle Body (although this only seems to help with idle) and looking at the N75 valve and the WasteGate Actuator.

    Anyone know a good way to test these parts to see if they are broken?

    I have had the odd EML but currently all clear.. I know, I need to get them read and will get this done in the near future.

    Any Help appreciated

  2. hades-

    hades- Well-Known Member VCDS Map User

    to save you money
    get it pluged in 1st
    to save just swapping parts
  3. warren_S5

    warren_S5 Moderator Staff Member Moderator VCDS Map User

    I've read somewhere on the net taht if you remove the vacuum line from the N75 to the wastegate actuator you basically disable the wastegate actuator - the wastegate will not open. The boost should be higher as it is no longer being limited. If you go WOT (Wide open throttle) you run the risk of overboosting and running lean or detonating, so drive the car with the hose disconnected, but do NOT under any circumstances go full throttle.

    If you remove the line and are able to achieve the correct amount of boost (whilst being careful not to overboost) then it may be a bad N75.

    If you remove the line and it runs the same then you have a wastegate problem, turbo problem, or a large boost leak.

    Even if you don't have a CEL, check the codes first before you do anything else. Not all codes trigger a CEL. Could be soft limp mode or something.
  4. jayorme

    jayorme Member

    Cheers Guys.. Will try the Vacuum line test tonight.. No worry about over boosting.. I'll pop it off and if I even feel the slightest boost I'll be a happy man and reconnect before replacing the part.

    Has anyone purchased a VAG COM cable from Ebay? Does the 2002 Audi have the 16 Pin Connector?

  5. jayorme

    jayorme Member

    Just completed Warrens idea and disconnected the top vacuum pipe from the N75.

    For the 1st time since purchasing my car in April I felt the Turbo and it pulled well :)

    Cleaned out the throttle body and re-connected the pipe and the cars running well now but no boost again.

    At least the test seemed to prove the turbo is ok :)

    Has anyone had these symptons with there car? Was it the N75 at fault or another reason (soft limp mode?)

    I've ordered a VAG COM cable but wont arrive till later this week.

  6. MDA

    MDA sploorer

    hope you get it sorted fella
    mines a 2002 1.8T it pulls from about 1900rpm and pulls like a train :)
    run a couple of tanks of v power through it when you have it sorted
    runs even better
  7. docurley

    docurley Moderator Staff Member Moderator

    It sounds like the N75 to me.
  8. Alan H

    Alan H Need a V8 or Bi-Turbo.......

    I had the same problem. I think it was about £40 from the stealers...

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