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Over-boost? Is this normal...?!

Discussion in 'A3/S3 Forum (8L Chassis)' started by nick4501, Sep 2, 2010.

  1. nick4501

    nick4501 Member

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    Hi guys.

    Since going stage 1 on my 1.8T A3 and fitting a Forge DV (with yellow spring), I've noticed that if I change gear during high boost, with my foot completely off the accelerator before doing so, the rev counter goes UP! Is this the DV recirculating the boost back into the system? Is it normal or do I have some sort of leak?...I can't image it is doing my clutch any favours...
     
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  3. rusty s3

    rusty s3 Member

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    do a vag-com scan and i bet it will tell you the clutch peddle switch is gone.
     
  4. danger S3

    danger S3 Member

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    I had this problem with my AMK too, the clutch switch on mine was well nackered but I also replaced the DV, N75, MAF, temp sensor and cleaned the throttle body
    I did them all individually and they all made a bit of a difference and now its sorted
    my N75 and temp sensor showed up as intermittent faults on vcds so replacing them was a no brainer and the MAF and Dump valve i replaced cause i figured after 100k miles they could do with it

    start with the clutch switch as its only about a tenner
     
  5. XFi

    XFi Active Member

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    Have this on mine but no fault codes... :(
     
  6. DJ_Troopa

    DJ_Troopa K1 Driver

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    I have this too and so do many others on here. There was a huge topic on this covered quite a while back now. I replaced the clutch switch but did nothing really lol. I've changed my MAF since then because i had to but that didn't make a difference either as some people have mentioned.
     
  7. stoneys3

    stoneys3 Member

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    same
     
  8. nick4501

    nick4501 Member

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    Well it's a brand new DV and I have just replaced the temp sensor, so can't be either of those to blame. Where can I get a clutch switch from online? Are they easy to fit?

    I'm pretty certain that I have 1 or more splits in my breather pipes, as it idles lumpy and seems to intermittently lose boost, so maybe that could be partly to blame?

    I've ran a VAGCOM check and it only reports the good old secondary air intake problem...
     
  9. sportstractor

    sportstractor Chugger

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    A vac leak can cause this but clutch swtich is the common one
     
  10. danger S3

    danger S3 Member

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    I ordered the clutch switch from Audi and went and picked it up. its fairly easy to change although a wee bit fiddly
     
  11. Dane

    Dane Had an 8L S3, a B5 RS4 now I have a B8 S4

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    I did alot of work on this last weekend.

    The clutch switch was replaced when my clutch pedal snapped. This did not cure the over revving.

    I had a new gearbox fitted and 20 miles later speedo stopped working, during this time the car didn't over rev.

    I get the speedo working and it starts over revving by quite alot, this suggested to me that the problem was electrical.

    No fault codes showed up, so i thought for £11 its worth trying another clutch switch, this didnt work either :sadlike:

    As I had two switches i thought what the hell I'll take one apart and see if i can figure out how it works and whether I can sort it out. Turns out its a fairly simple mechanism but my god is it fiddily! On both switches the black 'plunger' that moves as you use the pedal wasn't correctly attached to the simple sliding switch inside, so even thought the plunger was moving there was no actual switching happening. I correctly aligned the plunger with the sliding switch and hey friggin presto! over revving is 90% sorted (it now jumps by no more than 100 revs as opposed to around 800).

    I have no real experience of doing anything like this before but once you actually open it up its quite obvious what needs to happen. So if the new clutch switch doesnt work when fitted to the car take it apart get everything in the right place and you might have more luck.
     
  12. Lee172

    Lee172 GT3071

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    I will have to give it a go as mine does this slightly. My mate had a mapped s3 before which did this, he was trying to figure it out for months before he sold it. Would you say it was normal to do it by 100 revs?
     
  13. danger S3

    danger S3 Member

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    mine still does it by about 100 revs now compared to the 800 or 900 it did before so I would say that's normal or at least acceptable
     
  14. Dane

    Dane Had an 8L S3, a B5 RS4 now I have a B8 S4

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    :iagree:Im happy that it only over revs by a 100 its not really that noticable compared to what it was. And now its alot better I run the risk of having to fiddle around for another few hours and end up making it worse again so im not touching it lol.
     
  15. nick4501

    nick4501 Member

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    So the clutch switch is a dealer-only part? Does anyone have the reference code for it?
     
  16. Dane

    Dane Had an 8L S3, a B5 RS4 now I have a B8 S4

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    I got mine from TPS, I spoke to a local dealership and they said thats where they would get the part from anyway so I just went to them direct. I think the part number is 6q0927189 but TPS found it with my Chassis number and a brief explanation.
     
    #15 Dane, Sep 3, 2010
    Last edited: Sep 3, 2010
  17. nick4501

    nick4501 Member

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    Awesome. Thanks mate. Just out of curiosity, do Audi dealers get all of their parts through TPS?...Can you get things like specific Audi breather pipes, etc direct from them and dodge the extra price that the dealership will bolt on?
     
  18. Dane

    Dane Had an 8L S3, a B5 RS4 now I have a B8 S4

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    No worries,

    I've not had to replace any breather pipes (yet) and I'm not sure whether Audi get all of their parts from TPS but I imagine TPS or GSF would be able to get hold of what you need. Some one will be along to confirm but just ask what ever company you go with.
     

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