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Rotational knock

Discussion in 'A3/S3 Forum (8L Chassis)' started by rustynlc, Oct 2, 2013.

  1. rustynlc

    rustynlc Member

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    Hi folks, as the title suggests I have a 'rotational knock'. Basically when traveling at slow speeds I have knock comeing from the front of my car, it seems to be passenger side, it's there when I accelerate when I brake and when I turn, it kind of sounds like a chugging train, :
    the car: audi a3 1.8t Quattro, iv checked for tyre rubbing and found nothing, iv jacked the car up and span the wheel can see the brakes binding in any position on the brake disks, there is slight play if I rock the tyre horizontally as if checking bearings and it is literally 3 mill play, iv bought a set of wheel bearings to fit from tps could this play be busted bearings? Any ideas on what else to check, o and I'm replacing the bearings as a matter of course, it's had lots of work to keep it tip top and stacks of audi service history up to date, the front drop links (stabiliser bars) had recently been replaced front and back due to excesive play, so figured maybe the bearings took a bit of pounding, greatful for any input/ideas on what to check, iv also sourced a transfer box, hopefully the squeal that I have above 20mph+ will then be irradiated,
     
  2. Lavis89

    Lavis89 Well-Known Member
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    Had this exact same problem on my 1.8t quattro, get the haldex serviced! (oil and filter), never thought it would have made such a difference.
     
  3. JohnM100

    JohnM100 Well-Known Member
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    If it is mainly on turning and sounds fast compared to wheel speed then have a look at the inner & outer CV joints. If the noise is there in a straight line then more likely to be something else.
     
  4. Jason.s

    Jason.s Active Member

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    Mine does this on pull away forwards and reverse but when rolling at speed it goes. On coast town its started to make a slight ticking sound at lower speeds.

    Mines coming from the drivers side and when it knocks as you pull away you can feel it in the pedals.
     
  5. rustynlc

    rustynlc Member

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    It's mainly going straight, aaccelerating and let of and it appears, I may service the haldex, any ideas on the easiest way to change the oil/filter? I was thinking cv joints but its mainly in straight lines
     
  6. rustynlc

    rustynlc Member

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    This knocks slows when the car slows, and remains when I'm coasting at speed! Not sure we're it what to throw money at?
     
  7. rustynlc

    rustynlc Member

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    A quick update, seems if I turn left the noise disappears, but turn right it becomes more prominent, :/ really starting to bug me now, got ever so slight play rocking wheel at quarter to three angle on front wheels, ever so slight play at six ok clock position, so do people think this is maybe linked to wheel bearings or maybe inner cv joints
     
  8. Sham101

    Sham101 Member

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    check the sub frame bolts on the front one might be loose
     
  9. rustynlc

    rustynlc Member

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    Hi sham 101 I will check the sub frame bolt first thing, thanks for the reply
     
  10. rustynlc

    rustynlc Member

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    Basically the knocking noise has stopped, it's now a constant rumble, the interior shakes and rattles, occasional slight shake in te steering wheel can be felt but not all the time, very rarely, I'm an on call firefighter and I went out earlier to respond to a shout jumped in and noticed the rumbling on route to the station, once I got to the station I jumped out and could smell......fart! A real eggy smell, I got back after the call out and proceeded to drive home and the rumble was still there along with the car feeling like the brakes were randomly being applied, it almost felt like random superstitious misfire, the car idles fine, iv check all the obvious with regards to the rumble, drop links, flat tyres, suspension mounts, bushes, and for the eggy smell I'm puttin it down to the cat, could these problem be linked? Any ideas on what to check? As I said the random hesitation misfire is strange because its under load while moving but stationary if I hold it at different stages on the rev counter it doesn't mis or hesitate, gettin confused and annoyed now! Any help or tips would be greatly accepted, many thanks folks
     
  11. Sham101

    Sham101 Member

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    i had same prob on mine replaced all the bolts from tps cost me £15 worth doing it
     
  12. Sham101

    Sham101 Member

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    check if front wheel nuts are tight?
     
  13. rustynlc

    rustynlc Member

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    Yeah front wheel nuts are torqued to 120nm as told by mr Haynes! Looks like ill be booking off call! :(
     
  14. Sham101

    Sham101 Member

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    have you checked them
     
  15. Sham101

    Sham101 Member

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    ?
     
  16. Vex182

    Vex182 Guess what I drive...

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    Sounds like wheel bearings. No play in the lower ball joint? What about perhaps a loose brake calliper?
     
  17. rustynlc

    rustynlc Member

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    Yeah iv checked them sham101. And hi vex182 iv checked brake calipers all seem fine and secure, iv got slight play when I rock drivers side front wheel horizontally, this to me suggests track rod ends, but I suppose it could point towards wheel bearings.
     
  18. rustynlc

    rustynlc Member

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    Loosing the will to live! Now iv discovered that upon accelerating the car randomly stutters and splutters, not all the time but randomly, starting to think this cars a lost cause! Perseverance is the key I suppose
     
  19. mattyboy199

    mattyboy199 Active Member

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    I bet its the power steering pipe on the drive shaft !
     
    Pubemammal likes this.
  20. rustynlc

    rustynlc Member

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    Mattyboy199 any more info on your post? What side should I looking? And is this in relation to the hesitation?cheers for your post bud,
     
  21. Tooks

    Tooks Active Member

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    Sounds to me like you've got at least two issues going on?

    Knocking sounds etc shouldn't be linked to misfires and/or funny smells, it could be you've got a coil pack on the way out?

    Re the knocking, you shouldn't have any play in any of the suspension components. 3mm is a lot!

    Most common sources of knocking on the A3/S3 in my experience are top mounts, ARB bushes and/or collars, drop links, track rod ends and ball joints. Also, noises can travel, so check rear drop links and rear ARB bushes and the bar itself.

    If it's none of those, then worn drive shaft cv joints are sometimes culprits, and of course badly worn wheel bearings. If you're getting a droning/whirring sound then it could be wheel bearings, if it's more like clicking then could be a cv joint. Sometimes the steering rack can knock too, but doesn't sound like that's the case here.

    I would check your top mounts are secure and eliminate the cause of the play first though. Then I'd get a new coil pack and start to switch them out one by one to see if the misfire goes, assuming you can't get the car scanned with vag-com or similar which should tell you which pack/s are going.
     
  22. rustynlc

    rustynlc Member

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    Tools thanks for the info, iv recently replace the front and back drop links but I shall give the other componants a look tomorrow, a for the faulty coil pack no codes show up on my generic sealed scanner but would vagcom show them?
     
  23. rustynlc

    rustynlc Member

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    #tooks. #as for. And #sealey damn iPhone auto correct
     
  24. rustynlc

    rustynlc Member

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    A local vag modification place called redub ltd are meeting me to scan my car with vagcom in abit so will report back findings,
     
  25. rustynlc

    rustynlc Member

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    Ok, scanned with vagcom, lambda sensor fault, cleared fault code, car now runs sweet as a nut, hopefully fault doesn't come back, one other code popped up, something to do with a sticking flap? But again reset the code and it didn't return, now just to figure out the rotational knock
     
  26. sportquattro

    sportquattro Active Member

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    Rotational knock/rumble sounds like wheel bearings to me, CV joints sounds like more of a click when they are knackered. If you can rock the drivers side wheel 3mm somethings definitely worn/knackered you should not be able to feel any play
     
  27. rustynlc

    rustynlc Member

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    Hi sportquattro, yeah something's definatly worn, cleared the workshop today so going to do the wheel bearings and see if that sorts it, hopefully my poly bushes arrive tomorrow so I can chuck them in aswel,
     
  28. rustynlc

    rustynlc Member

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    A nice quiet at :D I replaced the track rod ends on both side an also week bearings, the car no longer bumps or knocks :), just gotta sort this blasted stutter/judder! Stuck it on vagcom came up with faulty lambda sensor, replaced it with genuine audi lambda sensor and it still the same, not constant but when it starts boy it's annoying! No other fault codes stored??? Any ideas???
     
  29. rustynlc

    rustynlc Member

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    Changed fuel filter aswell......... nothing, still the same?
     
  30. Tooks

    Tooks Active Member

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    Have you checked the coil packs yet? Dodgy ones don't always show up on a scan.

    Have you got a new spare coil pack? It's practically a legal requirement for VAG turbo cars to carry one in the boot at all times isn't it?! :sm4:

    Swap each pack out one at a time and see if the problem goes away. Also check the wiring isn't cracked to the packs. On that subject, did you check the wiring to the new lambda sensor when you replaced it? It's in a harsh environment and prone to going brittle/cracking.
     
  31. rustynlc

    rustynlc Member

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    Hi tooks I did give the lambda wires a brief inspection, all looks fine, I'm going to order a coil pack to start swapping them out to see if that sorts the problem, would coil pack/s failing be an intermittent problem? And I did notice today when I was checking the coil pack wires that the charcoal canister near the washer bottle in the engine bay has a split pipe going to it, obviously not sure if this could cause the problem , but only reason I spotted it is because when the engine starts to judder the motor/valve on the charcoal canister starts to click real loudly.
     
  32. Tooks

    Tooks Active Member

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    Coil packs are witchcraft mate, they really are! The reason I mention it is I had one on my old A4 that only played up when hot.

    I know it's kits more checking, but have you changed the vacuum pipes, particularly the one under the manifold? They perish too on cars of a certain age and cause all manner of running problems.
     
  33. rustynlc

    rustynlc Member

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    No not replaced any yet, I did have a look at the pipes, and the one under the manifold, no obvious signs of perish or damage, I do want to renew my pipes for silicone pipes so maybe will do this sooner than I first intended, I'm not sure of the name of the pipe but at the back of the engine there is a metal pipe section that is near to the turbo, it's around 1"-1"1/2 in thickness it has a small pipe coming of of it that looks as thought it's been rubbing against the heat shield that is cliped around the metal tube, so I'm going to also replace this pipe too
     
  34. rustynlc

    rustynlc Member

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    Juddering from cold now!, no faults logged, slutters and clears above 2500-2700 rpms,
     
  35. rustynlc

    rustynlc Member

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    Just checked all pipes, fuel pressure regulator to inlet manifold was slightly split, replaced it....... Still s***! It's pretty much constant hesitation and stuttering now, but if I keep my foot planted it almost 'pops' past the judder, still no codes logged!
     
  36. rustynlc

    rustynlc Member

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    Aright trying to get to the bottom of this no as it's starting to grate a little! I change sparks, checked wire loom to coil packs, checked for split hoses, replace fpr to intake manifold hose, car still runs s***! Idles lumpy and when I boot the car it struggles but clears, I thought maybe it could be the maf I unplugged it and it still ran s***, iv not long had new coil packs but am thinking maybe i should buy some new ones and give them a whirl! Any other ideas?
     
  37. rustynlc

    rustynlc Member

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    Sorted the hesitation (touch wood) after abit of diagnosis it turnt out to be a failing coil pack! Didn't throw up a code on vg com but after disconnecting the rest of coil packs one by one made the engine struggle more, apart from the offending coil pack, when this was disconnected the engine lumpy was didn't change, replaced this coil and hey presto no more lumpy idle and when I put my foot down the powers back :) cheers for all the helps and tips folks
     

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