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lack of power. Any idea?

Discussion in 'A3/S3 Forum (8L Chassis)' started by mattstead, Nov 5, 2003.

  1. mattstead
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    mattstead New Member

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    [Nov 5, 2003]
    Hi there, I'm trying to help a friend diagnose a problem on his 2000 A3 1.8 Quatrro T Sport (70K miles) and hope that you can help. Car drives great and really flies up through the gears, but every so often (possibly getting more frequent), if he drops it down a gear for an overtake etc (particularly 5 to 4, and 4 to 3), then there is very little power and the car is very flat (particularly around 4K rpm) and fails to gather speed, so he just has to change back up.

    Having read some other posts I'm wondering about N75 valves, Diverter Valves, coil packs, etc, etc ?????? Please can someone help?

    Thanks.

    Matt.
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  3. jesters3
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    jesters3 Active Member VCDS Map User

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    [Nov 5, 2003]
    Morning,

    Could be the cluth or is that fine. If it were coil packs it would be dead, cambelt change soon for the A3 though. Hmm, do a search on the forums to see if that brings anything up. Or wait for the dudes to get their brains in gear.

    Cheers and welcome to tbe boards.
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  4. AlexStanley
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    AlexStanley Member

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    [Nov 5, 2003]
    It's too early in the morning yet /ubbthreads/images/graemlins/wink.gif

    A warm welcome from me too, Matt
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  5. benk
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    benk Member

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    [Nov 5, 2003]
    Again, from other posts on here I would have been tempted to say MAF but I would expect that to affect the changing up through the gears as well... from what I remember, a bad MAF usually means low power from 4000 revs up?
    Time for that morning cuppa..
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  6. Highlander
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    Highlander New Member

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    [Nov 5, 2003]
    Sounds similar to a problem I had a few years ago with a 1.8 T Sport. There was a problem with the throttle position feedback to the ECU. I had a new throttle body fitted under warranty and it cleared the problem up.

    Donald
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  7. Administrators
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    Administrators Administrator Staff Member Administrator

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    [Nov 5, 2003]
    Post revo trial? /ubbthreads/images/graemlins/tongue.gif
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  8. mattstead
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    mattstead New Member

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    [Nov 6, 2003]
    I've heard mention of the DV, but what does it do, and where is it / what does it look like.

    Thanks,

    Matt.
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  9. RichA3Turbo
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    RichA3Turbo ...Watching you! Staff Member Moderator

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    [Nov 6, 2003]
    [ QUOTE ]
    mattstead said:
    I've heard mention of the DV, but what does it do, and where is it / what does it look like.

    Thanks,

    Matt.

    [/ QUOTE ]

    DV... Right...

    Well the turbo runs on exhaust gas right, so its spins as long as gas is going through it. Petrol engines have a throttle, so when the throttle is closed, without a DV, the turbo has nowhere to push the air, so the pressure builds up and stalls the turbo, which would mean that it would not kick back in again after a gear change til about 4000rpm. The DV (diverter valve) does exactly that... it diverts the air so that the turbo keeps spinning, but only at a certain pressure. So when you close the throttle, the pressure between the throttle and turbo builds up, and the DV opens, vents the air back into the system just after the airbox, and keeps the turbo spinning! Simple!

    Now the old OE DV's are ****! and regularly fail, so an aftermarket DV would be a wise move (or the latest revision of the OE version) Aftermarket DV's include Forge, AmD, Bailey and Stratmosphere!

    Hope that helps!

    Rich
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  10. viper
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    viper Member

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    [Nov 6, 2003]
    i think its the clutch on the way out,
    see the problem i had was when i punch the accel'tor the engine would rev but not move. took it to a garage who said the clutch was slipping cost me £388 for new 1.

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  11. Gambba
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    Gambba Active Member

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    [Nov 6, 2003]
    [ QUOTE ]
    viper said:
    i think its the clutch on the way out,
    see the problem i had was when i punch the accel'tor the engine would rev but not move. took it to a garage who said the clutch was slipping cost me £388 for new 1.



    [/ QUOTE ]

    No I agree with Rich DV sounds like a good option, and MAF as a possible second amognst other things. This doesn't sound like clutch, as a slipping clutch allows revs to continue to rise quicker than normal, as there's no load, but with no gain in acceleration. Easy way to check clutch is handbrake on a nd try and pull away if car sinks down when clutch is released slightly (without throttle) then clutch is most likely fine.
    #10
  12. mattstead
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    mattstead New Member

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    [Nov 8, 2003]
    Right, thanks for the suggestions, I think a new DV valve will be fitted just to be on the safe side. Yesterday the car went to the local Audi dealer who kindly offered to replace the "air density meter" (I assume that this is the same as the airflow meter I used to have load of problems with on my 205gti? Is this the same as the MAF?) for a cool £300 !! , my local Euro car parts place said more like £150, but then told me that I could easily clean it first with petrol or carb cleaner. Now, if it's like my old 205GTI, then I can do this no problem, but what does it look like and where abouts is it / any tips / photos etc.

    All advice greatly recieved.

    Thanks.
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  13. mattstead
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    mattstead New Member

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    [Nov 8, 2003]
    What a great forum, just done a search on MAF cleaning and found exactly what I want.

    Thanks.

    #12
  14. Mike.M
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    Mike.M Well-Known Member

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    [Nov 8, 2003]
    Online HAYNES MANUAL to me!
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