1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

A4 1.9 TDI Motorway Speed Limp Mode

Discussion in 'Diesel forum' started by inigoj, Jan 22, 2007.

  1. inigoj
    Offline

    inigoj Member

    Joined:
    Dec 4, 2004
    Messages:
    263
    Likes Received:
    0
    [Jan 22, 2007]
    Recently my 97 A4 TDI 110 has started to go into limp mode when accelerating over 80mph.

    There are no problems accelerating uphill etc at lower speeds, just seems to be 5th gear?

    I have just been checking all the hoses and found that the small diameter tube from the inlet manifold to ECU pressure sensor was full of liquid. Could this affect anything?

    I have already changed my maf and boost N75.
    #1
  2. Ads

    Ads

    [Oct 23, 2014]

  3. Caesium
    Offline

    Caesium My BM is fixed!

    Joined:
    May 26, 2004
    Messages:
    4,879
    Likes Received:
    4
    [Jan 22, 2007]
    If the engine went into limp you'd only be able to do about 15-20mph.
    the liquid in this tube, what was it? whatever it was, its certainly not right.
    #2
  4. inigoj
    Offline

    inigoj Member

    Joined:
    Dec 4, 2004
    Messages:
    263
    Likes Received:
    0
    [Jan 22, 2007]
    When i say 'limp mode' i mean it is overboosting and shutting off the turbo.

    It will still accelerate but just as a non-turbo lump.

    Cycling ignition does reset it.
    #3
  5. Mcgough
    Offline

    Mcgough Member

    Joined:
    Oct 13, 2004
    Messages:
    847
    Likes Received:
    0
    [Jan 22, 2007]
    yea my last 130 Q did this when accelerating past 100mph, at exactly 100 it would go into limp mode,

    it went back to audi several times, they changed the Maf, the valve, then re-programmed Ecu, finally replaced Ecu, then eventually found the vane was sticking open on turbo, so they replaced it had no bother after that.

    you still under warrenty??
    #4
  6. Caesium
    Offline

    Caesium My BM is fixed!

    Joined:
    May 26, 2004
    Messages:
    4,879
    Likes Received:
    4
    [Jan 23, 2007]
    Do you mean Wastegate?
    #5
  7. Mcgough
    Offline

    Mcgough Member

    Joined:
    Oct 13, 2004
    Messages:
    847
    Likes Received:
    0
    [Jan 23, 2007]
    ?????i got told Turbo Vane?? thats audi for you make special names up
    #6
  8. mattc83
    Offline

    mattc83 New Member

    Joined:
    Sep 29, 2004
    Messages:
    5
    Likes Received:
    0
    [Jan 25, 2007]
    the tdi have a varable vain turbo. bascally it is little flaps in the exshaust section of the turbo. they move to alter the angle of flow on turbine blades to reduce turbo lag
    #7
  9. Mcgough
    Offline

    Mcgough Member

    Joined:
    Oct 13, 2004
    Messages:
    847
    Likes Received:
    0
    [Jan 25, 2007]
    .......thats the little buggers!!
    #8
  10. Caesium
    Offline

    Caesium My BM is fixed!

    Joined:
    May 26, 2004
    Messages:
    4,879
    Likes Received:
    4
    [Jan 25, 2007]
    I have seen what you mean now, they're lots of small vanes that adjust angle to control flow of exhaust gas onto the turbine blades. This technology does not need a wastgate.

    I'll hold up my hands and say I have never seen this in a turbo, but then again I've only ever had the turbo on a petrol engine apart, and apparently this technology is rare on petrol.

    See here http://www.autozine.org/technical_school/engine/tech_engine_3.htm#VTG
    #9
  11. inigoj
    Offline

    inigoj Member

    Joined:
    Dec 4, 2004
    Messages:
    263
    Likes Received:
    0
    [Jan 25, 2007]
    After towing a car on a very heavy twin axle trailer 500 miles today, my overboosting problem has vanished.

    Infact my car seems more powerful than it did when i first bought it, accelerates well, right through to 5k, pedal to the metal in every gear.

    Does this mean that the problem was a sticky VNT mechanism?
    #10
  12. Mcgough
    Offline

    Mcgough Member

    Joined:
    Oct 13, 2004
    Messages:
    847
    Likes Received:
    0
    [Jan 25, 2007]
    ...possibly. but possibly not apparently mine was sticking in the max/open position which made the car overboost while changing from 4th to 5th.

    possibly you had a diff problem which, now with a bit of italian tune, you have rectified!!!
    #11

Share This Page