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S3 hesitation on acceleration?

Discussion in 'A3/S3 Forum (8L Chassis)' started by RacingTeatray, Aug 31, 2005.

  1. RacingTeatray
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    RacingTeatray Freezing in Moscow

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    Recently my S3 (BAM engine code) has starting to be a bit hesitant on acceleration. When cold it can be particularly recalcitrant in first. On very low throttle openings in first (eg in crawling traffic) it kangaroos rather embarrassingly. And then sometimes on full-bore acceleration (eg overtaking), it can accelerate at a certain rate and then suddenly the power will surge and the car leaps forward in a manner that suggests there was a slight blockage that has just cleared. It never feels particularly sluggish - it's just this sensation of sudden surge of extra acceleration that can rather catch me out (particularly if I wasn't intending to go any faster).

    Could this be MAF-related (I've never really understood what the MAF problem was so not sure)?
    #1
  2. clarko
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    clarko Member

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    hello mate

    certainly sounds like your maf to me but needs some diagnosis and logging to be sure for certain. Try disconnecting the MAF and see if that improves performance. I run a company called www.vagcheck.com and would be more than happy to have a look at your car - am based SW London - let me know what you want to do.

    cheers

    J
    #2
  3. madvw
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    madvw Active Member

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    dude, this ain't a place to advertise..


    rules:

    Please note that advertisements, chain letters, pyramid schemes, and solicitations are inappropriate on this forum and will be removed without notice. User accounts posting such threads may have their account and/or access to the site restricted

    as for the problem, sounds to me like a knacked throttle potentiometer rather than a maf.
    #3
  4. scoTTy
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    scoTTy Active Member

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    5 out of his last 6 posts have been adverts (ok ones legit).

    Hey but why have rules eh? /ubbthreads/images/graemlins/noidea.gif
    #4
  5. clarko
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    clarko Member

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    nice of you to count scotty - knew i could count on you for support :-/
    #5
  6. imported_bantam1
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    imported_bantam1 Guest

    [ QUOTE ]
    hello mate

    certainly sounds like your maf to me but needs some diagnosis and logging to be sure for certain. Try disconnecting the MAF and see if that improves performance. I run a company called www.vagcheck.com and would be more than happy to have a look at your car - am based SW London - let me know what you want to do.

    cheers

    J

    [/ QUOTE ]

    For free? As in the spirit of the forum?

    Kind offer.

    B.

    P.S. I had a similar sounding problem on a MkIv golf I had and replaced the MAF to no avail. Never did find the root cause but this was only an intermittent fault.
    #6
  7. scoTTy
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    scoTTy Active Member

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    [ QUOTE ]
    nice of you to count scotty - knew i could count on you for support :-/

    [/ QUOTE ]

    Oh sorry. I hadn't been told that you could do whatever you like on here. I'll get back in my box. /ubbthreads/images/graemlins/shutup.gif
    #7
  8. benk
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    benk Member

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    I thought MAF tended to be gradual loss of performance as **** got baked onto the internal wire that is used to measure resistance (based on cooling effect of airflow over the wire I think). I agree that problem is more likely to be something else.
    #8
  9. Khufu
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    Khufu Active Member

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    when my MAF was faulty it caused hesitaion and flat spots. A faulty coolant temp sensor can cause it to run rough when cold too.
    #9
  10. starski4578
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    starski4578 Member

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    I'd just like to say my 99 1.8T quattro has problems exactly as described above especially in first and second gear. Its really getting me down now as ive taken it to awesome gti and they said over the phone it was probably the maf but when i brought it in the said the maf was ok but the engine temp sensor needed replacing. The thing is it has improved slightly but there is still that sudden hesitation of power mainly at low revs which jerks the car and makes you look a fool. Anyone have any suggestions what to do i've taken it in twice now but its not throwing up any error codes in the ECU? PLEASE HELP ME as my friends 1.8T gti is doing me 0-60 and that cant be right /ubbthreads/images/graemlins/cry.gif!!!
    #10
  11. starski4578
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    starski4578 Member

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    If you find out what it is can you let me know as my 1.8T quattro is doing EXACTLY the same thing. I sympathise with you mate! i had the engine temp sensor replaced and the maf is ok also i replaced the dump valve but the problem is still there. /ubbthreads/images/graemlins/cry.gif
    #11
  12. RacingTeatray
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    RacingTeatray Freezing in Moscow

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    What does the throttle potentiometer do?

    The car's quite low mileage - 31k - but I have managed to rack up nearly 7k miles since it was last serviced in May.
    #12
  13. madvw
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    madvw Active Member

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    It only exists on DBW cars, for obvious reasons. The throttle potentiometer is in the accelerator pedal. It measures how hard you have your foot planted in the pedal, then tells the ecu accordingly.

    When mine went, i lost the ability to pull away slowly, and it was an all or nothing scenario - cause the ecu didnt know how much acceleration i was giving it. The car also wouldn't idle, as it couldn't tell when my foot was OFF the pedal. It was a real nightmare., the car used to jerk when pulling away too.

    They are a complete plug in unit, you get a new pedal, and box, which just plugs in. Mine went at 27k miles.
    #13
  14. starski4578
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    starski4578 Member

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    Just got off the phone to audi and they have quoted me £350 for the potentiometer as she said its part of the throttle body, does anyone no anywhere else i could aquire one cheaper. The car has done 40K so by the sounds of it this could be at the heart of the flat spots and hesitations.
    Its really frustrating because its not always noticable, the worst time is in the morning while the engine is cool.

    One thing i forgot to mention my fan will go on and off every couple of seconds even from cold.
    You can see the lights dimming at night as it keeps kic /ubbthreads/images/graemlins/noidea.gifking in and out...
    #14
  15. Khufu
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    Khufu Active Member

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    thats not right! sounds like the temp sensor in the radiator is faulty.
    #15
  16. starski4578
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    starski4578 Member

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    I just had the engine temp sensor changed but is there another one thats just for the radiator?
    Cheers
    #16
  17. RacingTeatray
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    RacingTeatray Freezing in Moscow

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    It almost feels like I have a dirty batch of fuel but having driven nearly 1200 miles last weekend which chewed through the best part of 3 tanks of super-unleaded, that seems unlikely.

    Car says it wants a service in 2.5k miles time so almost wonder if it's worth taking it in early? But seems odd as has only done 7k miles since the last service which was in May. Ok so I've been racking up the miles but they've been mostly motorway miles so am surprised how short the interval is.

    It's still under manufacturer's warranty so should be ok if anything needs replacing.
    #17
  18. fasteddie
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    fasteddie Member

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    interesting, i have a hestitation around 5000rpm but only in 4th or is it 5th, a high gear anyway. i did have the MAF checked by AUDI stealer and it checked out fine, any ideas??
    #18
  19. AL_B
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    AL_B Active Member

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    Similar ongoing problems with my S3, as most people on here know. Hesititation around 4000 rpm, more reproducable when the car is cornering, which is wierd.

    Not going to say anymore about it in this thread, as I have discussed my cars problems in many threads now - so I don't want to clutter this one up.

    But, its a common problem this hesitation thing, and could be caused by a variety of things. Best thing to do is do a search on "Power problems" or "hesitation", both here and on other forums like tt-forum.co.uk etc. There are lots of folk who have been or are in the same boat.

    But if you do get it sorted, please post what fixed it.
    #19
  20. starski4578
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    starski4578 Member

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    Finaly i think ive put to rest the hesitation problems. After taking it to a well known GTi dealer in manchester twice , only for them to tell me the engine temp sensor had to be replaced which to be fair helped a little.But the lag was still noticeable. They told me it wasnt the MAF...having read lots of suggestions on this forum i unplugged the maf and the car ran silky smooth and put a smile back on my face. Thanks for the advice, i have now ordered a new maf. Can anyone tell me if it will cause any damage buy having it unplugged and if not then why is it there!!!!
    Cheers /ubbthreads/images/graemlins/woohoo.gif
    #20
  21. Khufu
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    Khufu Active Member

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    your engine could run lean in the worst case and burn out a valve but i'd reckon that would be an extreme case only. There is a current sent across a wire in the MAF, the faster the air passes over it the more current is required to maintain the same resistance. This is measure and converted to air speed entering the engine. (More or less LOL)
    #21
  22. RacingTeatray
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    RacingTeatray Freezing in Moscow

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    My local Audi dealer over the phone have suggested over the phone that it could be either the MAF, the temperature sensor or a sticky throttle body (is this the same as a potentiometer?).

    They want it in for inspection to identify the fault but indicate that the cost will be covered by the warranty as for the moment the car still under original factory warranty rather than the approved used warranty (it's not 3yrs old until end of the year).
    #22
  23. starski4578
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    starski4578 Member

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    cheers for the head banging explanation khufu! got me scared now might leave it plugged in till the new one arrives!!
    #23
  24. RacingTeatray
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    RacingTeatray Freezing in Moscow

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    My car is going in for an inspection on Wednesday so shall update with any findings.
    #24
  25. imported_Stewart
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    imported_Stewart Guest

    [ QUOTE ]
    Finaly i think ive put to rest the hesitation problems. After taking it to a well known GTi dealer in manchester twice , only for them to tell me the engine temp sensor had to be replaced which to be fair helped a little.But the lag was still noticeable. They told me it wasnt the MAF...having read lots of suggestions on this forum i unplugged the maf and the car ran silky smooth and put a smile back on my face. Thanks for the advice, i have now ordered a new maf. Can anyone tell me if it will cause any damage buy having it unplugged and if not then why is it there!!!!
    Cheers /ubbthreads/images/graemlins/woohoo.gif

    [/ QUOTE ]

    How much was the MAF m8?
    #25
  26. starski4578
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    starski4578 Member

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    The Maf cost 90 after vat from audi thats with taking my old one in too! argh!
    #26
  27. RacingTeatray
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    RacingTeatray Freezing in Moscow

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    Right well Docklands Audi tell me the MAF was faulty and it's been replaced under warranty so all should be well when I collect it this evening. I shall let you know.

    On the separate point I mentioned about the oddly short service interval - the mystery is solved and it's a shocker for the franchised dealer who sold me the car (who shall remain nameless)!

    It transpires that when I bought the car in May (approved used note!), it wasn't serviced after all, despite me being assured by the salesman that it had been and there being a corresponding stamp in the book. The 9,300 miles "reset" reading on the indicator at the time was purely coincidental and apparently this led somebody to think it had been serviced and so they stamped the book.......and told me when I bought it that yes it had just been serviced. Apparently.

    This came to light this morning when Docklands Audi, when asked about the short service intervals, pointed out that the car hadn't been serviced since April 2004. Which was something of a surprise. So I've just kicked up a fuss, mentioned that I'm a lawyer, mentioned the words "negligent misstatement" and listened to the ensuing squeaks of fright at the dealership. This is a particular perk of being a lawyer which has to be prefaced with the words "I don't mean to be difficult but I'm a..." for maximum effect.

    Anyhow I've settled for them performing a full-on long-life service next week for free and hopefully that'll be the end of it. I suppose I could have made their life harder but frankly no harm has been done if they now service the car as it is still within the acceptable variable servicing interval.

    But generally v poor form for a franchised dealer
    #27
  28. scoTTy
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    scoTTy Active Member

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    In case you weren't aware they've got the worst reputation that I'm aware of. /ubbthreads/images/graemlins/crazy.gif
    #28
  29. RacingTeatray
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    RacingTeatray Freezing in Moscow

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    Who do? I didn't name the dealership at fault so far as I can tell.

    Anyway having collected my car this morning, it's now running beautifully and smoothly so it seem the MAF was to blame.
    #29

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