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Slow acceleration - Diverter valve???

Discussion in 'A3/S3 Forum (8L Chassis)' started by ROBS3, Jun 1, 2010.

  1. ROBS3
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    ROBS3 Member

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    Hi Guys,

    Got a quick query...

    I just had my diverter valve replaced at Audi. On the drive home the car seemed fine (all motorway). But when I drove it the following day the acceleration seemed quite 'flat'. It seems ok up to 3k RPM anything over that it just seems flat, as if I'm not getting as much boost, I wouldn't say it's 'slow' but it certainly isn't as punchy as before.

    The car is completely standard, and they replaced the valve for a standard one (not Forge etc).

    Could the lack of acceleration be down to a faulty valve?
    Unfortunately I don't have VAG COM, and I can't get to the garage for a while, but would like to diagnose the issue sooner rather than later.

    Any help or advice would be appreciated.

    Cheers
    Rob
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  2. mark_sarah
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    mark_sarah Limp mode!

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    The DV that was replaced, was it a standard DV?
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  3. ROBS3
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    ROBS3 Member

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    Yeah, the original one was standard too.
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  4. MintyS3
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    MintyS3 Works 60% the time, Everytime.

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    Boost leak?
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  5. jojo
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    jojo S3 Drift King! Staff Member Moderator

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    I would check the hoses around the DV to see if they have blown off, it's common to not do them up tight enough, I've done it myself. Failing that, where abouts are you based? maybe someone local can VagCom it for you?
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  6. ROBS3
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    ROBS3 Member

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    Cheers for the input guys.

    I'm near Hampton Court - Middlesex/Surrey way.
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  7. emery1990
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    emery1990 Active Member

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    Id say check the hoses too, if its happened after the dv replacement, just check all the boost pipes too though.
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  8. ROBS3
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    ROBS3 Member

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    Cheers. I'll have a look over the weekend, and see if there is anything out of place.

    I take it, it would be pretty obvious if something isn't on properly, or where it shouldn't be?
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  9. Dansmith
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    Dansmith Member

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    Is your traction control light stuck on? normally this signals a boost leak!
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  10. leshkin
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    leshkin Speeding in reverse gear

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    I'm in Ascot, Berks and have vag-com, so if you can get to me we can scan/log to see if there are any obvious issues.

    One thing to check is if the new DV is fitted properly.
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  11. ROBS3
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    ROBS3 Member

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    The traction control light hasn't come on Dansmith.

    Cheers leshkin, I'll have a look this weekend, but may have to pop over for a quick scan at some point - cheers mate :thumbsup:
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  12. ROBS3
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    ROBS3 Member

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    Hi guys,

    Sorry to bring up this post again...

    I was just going to book the car into the garage, when it seemed to sort itself out!
    I was over taking a lorry, when the engine made a strange whistling noise (different to the turbo whistle) and the cars acceleration seemed to behave how it used to prior to getting a new diverter valve, changed gear (whistling changed back to normal turbo sound) and just kept accelerating as it always used to. For a couple of days the car was driving like a dream - I was so happy. :yes:

    BUT - when I was driving back from work this evening, I pull onto the motorway, accelerating quite hard, gets to about 4-4.5k revs and it just went flat again (mid acceleration), and it seems to have lost it's edge again :(

    Just wondering if you guys may have an idea what it may be? I guessing this rules out a leaky pipe?

    Cheers
    Rob
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  13. ROBS3
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    ROBS3 Member

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    Anyone?
    Any help would be appreciated :icon_thumright:
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  14. hartey
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    hartey Member

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    Sorry for bump, You get it sorted?
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  15. ROBS3
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    ROBS3 Member

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    Yeah - all sorted now thanks mate.
    It was the N75 valve, causing it to overboost and go into limp mode - but all good now!

    Cheers
    #15
  16. [Dave B]
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    [Dave B] Rrrrrrrr-tech

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    If you don't mind me asking, how much did the N75 set you back and did you ever get it vagcom scanned? Just curious to see if it logged a fault?
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  17. ROBS3
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    ROBS3 Member

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    I think it was around £45. I got a VAG specialist to look at it in the end. I don't know what the actual code was but I believe it was just an overboost error. So we had to try a few bits before diagnosing the N75. We replaced the MAF, boost sensor and tried a different diverter valve, all of which didn't rectify the problem so tried the N75 and ta-da bingo!

    HTH
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