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WHAT JUST HAPPENED ?????

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by white.akita, Nov 29, 2011.

  1. white.akita
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    white.akita Member

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    I was driving down the motorway in my 2002 a4 1.9tdi quattro avant at around 80mph for around 30 minutes, i slowed to leave the motorway but when i then tried to accellerate there was a violent vibration through the whole car and the car was struggling to accellerate.
    this lasted for a few mile but then completely dissapeared and the car drove perfectly for the remaining 20 mile home even when i was redlining the car trying to replicate it.
    im thinking maybe a diff has completely disintegrated inside or some sort of prop shaft problem, can anyone shed any light on what may of caused this ?
    #1
  2. marktdisport
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    marktdisport Active Member

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    you'd certainly know if your diff blew m8 when you say struggling to accelerate do you mean lack of revs ?? holding back ?? or revving ok just not performing ??
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  3. white.akita
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    white.akita Member

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    by struggling to accelerate i mean it was like the wheels where seizing solid and the engine was fighting against them, but i forget to add when coasting at any speed the car was fine it was only when i went to accelerate that the extremely violent vibrations began.
    it felt like the cogs inside the diff were binding or that a drive shaft was not aligned properly.
    #3
  4. boya
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    boya Member

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    The mother in laws passatt 1.9tdi done something similar the other week, apart from her esp light was flickering as it was happening, turned out to be a injector.
    #4
  5. marktdisport
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    marktdisport Active Member

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    i was thinking more towards missfire issue !!! but just wanted to understand a bit more of the holding back
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  6. white.akita
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    white.akita Member

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    There was no warning lights on the dash at all, i dipped the clutch and the engine revved freeley and the car rolled freely, just under acceleration the problem occured
    #6
  7. Tooks
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    Tooks Member

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    Unit injector wiring harness in the cylinder head?

    Happened to my 1.9tdi A3 quattro, felt like you describe.

    It was intermittent at first, especially when the engine was hot, but eventually became permanent.
    #7
  8. jbcalvin
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    jbcalvin Member

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    CV joint? That's what happened to me earlier this year and sound similar......
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  9. swarcup
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    swarcup Active Member

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    dmf playing up?
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  10. white.akita
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    white.akita Member

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    If it was the harness making the car run so badly wouldnt i have a dash warning light on?
    if it was cv joint how would it now be fixed and i thought it would of pulled badly to one side?
    Again possibly dmf but how did it fix itself?
    it was shaking very very violently on acceleration.
    Last edited: Nov 29, 2011
    #10
  11. beachbuggy
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    beachbuggy Active Member

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    Water in the injection system. When did you last change the fuel filter or drain the filter of water?

    Either that or you went into limp mode.
    #11
  12. white.akita
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    white.akita Member

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    I have not touched the fuel filter in the 3 month i have had the car but i did order 1 a couple of days ago and should be here tomorrow, i will change it asap.
    #12
  13. jbcalvin
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    jbcalvin Member

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    with regards to the CV joint failing, it did it a couple of times to the missus on her way home, but once she stopped and got out of the car and I drove it it felt fine before completely failing on a motorway trip 10 days later.......

    It was a torn gaitor so the grease was leaking out slowly.....
    #13
  14. simon.m
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    simon.m Active Member

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    how do you drain the fillter ?
    #14
  15. beachbuggy
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    beachbuggy Active Member

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    there is a white cap on the bottom of the filter, you unscrew it and it drains out all the water. As water is denser than diesel it sinks to the bottom. If you get too much water in the filter, under high loads it can draw water in and cause rough running.

    Other than that I would take a bet on it going into limp mode, and that goes away when you turn the engine off and restart it.
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  16. white.akita
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    white.akita Member

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    i have changed the fuel filter and the same fault has just come back.
    i have a feeling it is fuel starvation but could be wrong.
    when i changed the fuel filter there was little fuel in it but the car had been running fine for the few days before i changed it, should the fuel filter have been full of diesel ?
    anybody got any other ideas what it could be ?
    im guessing tandem fuel pump or pick up pump in tank, when i switch the ignition on i cant hear the in tank fuel pump , should i be able to ?
    #16
  17. BlackQuat
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    BlackQuat Active Member

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    Fuel filters are normally filled with diesel.
    Can't offer much more than that though sorry.
    #17
  18. unitzero
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    unitzero Member

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    I had a very similar situation on my bora tdi, really jerky and no acceleration. Esp light did start to flash too. Turned out to be intermittent misfiring in one injector caused by the loom/harness. £35ish iirc from the dealers / tps and took about an hour to replace.
    #18
  19. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    It does sound injector/loom related. The loom issue is a common one on the 1.9's.
    #19
  20. white.akita
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    white.akita Member

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    I also have a lumpy idle again so i will look into getting the injector loom.
    Will audi know what i mean by injector loom? Anyone help with a part number?
    #20
  21. white.akita
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    white.akita Member

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    after a bit more research on the injector harness it seems like they rarely need replacing and that a clean up with contact cleaner should fix them.
    i will do just that on saturday and see what happens.
    #21
  22. Tooks
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    Tooks Member

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    I really would advise replacing the loom, for how much they cost. You've got to do more than half the job to just clean the contacts anyway?

    When I swapped mine out, the wires were hard and brittle compared to the new one, and the electrical resistance was much higher in the old one.

    The loom sits in a harsh environment, and not replacing it would only lead to uncertainty should the fault recur.

    It may not be the loom, but I would always have doubts about it by just cleaning it, and it may lead you to replacing other parts unnecessarily if the fault is still there following a cleaning attempt.

    My local Audi centre had them in stock, which suggests they are needed more frequently than we think.
    #22
  23. white.akita
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    white.akita Member

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    well i undid the round plug from the harness and sprayed contact cleaner on it then did the same to the plugs going to the injectors, i also squashed the terminals slightly in the harness so they fit tighten onto the injectors.
    so far the lumpy idle has gone,if the main problem does come back i will fit a new harness.
    #23
  24. white.akita
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    white.akita Member

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    well after 2 days the problem has come back.
    i will put a new injector loom on this time, does anybody know it the 1.9tdi and 2.0tdi injector loom are identical ?
    i ask because my local audi dealer does not have any in stock and there are a few for sale on ebay for the 2.0tdi.
    audi quoted me £52.52 for a new loom.
    #24
  25. stu_m
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    stu_m Active Member

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    im going to say no at a guess as they use different injectors for a start
    #25
  26. white.akita
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    white.akita Member

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    i have ordered a injector loom so waiting for it to come.
    the fault happened again today and when i went over a speed bump i heard a loud bang come from the passenger side front wheel area.
    so im now thinking its a cv joint or drive shaft issue.
    can anyone shed any light on what it may be ?
    #26
  27. Grangey.
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    Grangey. Member

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    Mate Im not being funny but this has been going on 3 weeks now and from what ive read youre already ordering parts on a whim/based on forum response. Dont get be wrong forums are very usefull places but this doesnt sound like a little fault like a flashing light or something. Surely its about time you take it to a local garage, explain what youve been experiencing, and get them to give it a look over.

    Hell if you think its a CV joint, put the car through another MOT if youre worried about hourly costs etc as they have to check them during that!
    #27
  28. white.akita
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    white.akita Member

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    No fault codes and it was motd about 5 weeks ago.
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  29. Tooks
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    Tooks Member

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    The bang you heard could be completely unrelated, or part of the problem. It's difficult to describe faults like this on the internet...

    I've just re-read your original posts, and there is nothing you describe in there that would make me think it was a driveshaft or cv joint. Those things are mechanical, and so I would expect them to fail and stay failed until they're fixed.

    The fact you can drive between juddering/lack of acceleration issues just reinforces that thought.

    If you've got noises coming from the front passenger side, then it's worth getting it up on a ramp for a look, as others have said. It could be completely unrelated, but still worthy of your attention in its own right!

    So, if it were me, I'd get the car checked/inspected, change the loom when it arrives and see where you are after that. It's easy to chase your tail with cars sometimes!
    #29
  30. white.akita
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    white.akita Member

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    one thing after another, i must have been parked too close to the kerb and when i reversed i ripped the whole lower front bumper off !
    anyone know of any cheap full front bumpers for sale ?
    #30
  31. white.akita
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    white.akita Member

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    i have changed the wiring loom and the car is no better.
    thinking now maybe injector.
    with the bonnet up i can rev the engine and when it settles to idle i can see the whole engine rocking but seconds later i can rev the engine let it settle to idle and the engine can idle perfectly with no shaking !!
    what the hell is wrong with it !
    #31
  32. white.akita
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    white.akita Member

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    Could it be fuel starvation, i cant hear the in tank fuel pump should i be able to? It starts perfect every time.
    #32
  33. adamss24
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    adamss24 Well-Known Member

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    It looks like the DMF is about to fail...
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  34. T0m
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    T0m Member

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    Matey if I was you stick it into a local Independant VW/Audi garage and get them to give it the once over, whats it going to cost £30 for an hour of there time, you've already wasted over 3 weeks on here as Grangey and a few others have said, its hard diagnosing faults over the net especially intermittent ones like your sort fella.

    I only say that as mine was idling rough the other day took it in and it was a simple valve on the air intake which happened to be sticking, £30 plus £25 to hook it up to diagnostics result and all sorted now.
    #34
  35. white.akita
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    white.akita Member

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    I dont have the cash to pay a mechanic.
    if it was dmf i cant see how it could get so bad where it is shaking the car and no power at all to being ok 10 mins later.
    #35
  36. white.akita
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    white.akita Member

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    Anybody know if i should be able to hear the in tank fuel pump priming when i turn the ignition on?
    #36
  37. Grangey.
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    Grangey. Member

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    Well frankly mate I suggest you start saving as youve already wasted £50 on a loom which wasnt needed and that could have gone toward a machanic who is actually LOOKING at the vehicle rather than looking at text on a screen.

    Honestly, youre wasting your time trying to diagnose such a big fault on a forum and you will WASTE money if anything like you already have, not save it by avoiding a mechanic.
    #37
  38. T0m
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    T0m Member

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    Mate I know money is tight but sorry I agree with Grangey £30 of that £50 you wasted could of given you an hour with a audi mechanic and it would of been money well spent, get it in the garage when you can and let them diagnose the problem then worry when they tell you what it is instead of trying to use a forum to diagnose your problems. I appreciate we are all here to try and help each other and will do our best but it is best you get it looked at if nothing to alay your fears of what the issue is.....

    Nothing pesonal mate, let us know how you get on fella!
    #38
  39. Andy_TDi
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    Andy_TDi New Member

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    You need it scanning for fault codes!! just because there isn't a dash(fault) light up doesnt mean there isn't fault thats stored on your ecu stop messing about with whim's based on your explanations of your fault and get it to a garage if you lived near me i'd scan it for you!
    #39
  40. white.akita
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    white.akita Member

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    Like i have said i have scanned it a few times and there is no fault codes. I will fix it myself. Im not paying main dealers a penny and there are no vag specialists anywhere near me. I also dont trust most general mechanics as they often mis diagnose things wrong that can end up costing punters thousands!
    Last edited: Jan 3, 2012
    #40

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