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a3 tdi multiple problems!! (doing my head in now please help)

Discussion in 'A3/S3/Sportback (8P Chassis)' started by gizm0, Mar 29, 2011.

  1. tdi-man

    tdi-man Well-Known Member

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    what do you mean ???




     
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  3. a8 tech back

    a8 tech back Member

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    just enter some data for the shop name and equip number as some controllers will not allow coding etc if the vcds has no data filled
     
  4. tdi-man

    tdi-man Well-Known Member

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    ok will do put vcds lead away now raining here.....

    use to work on an old 812.4 lead
     
  5. tdi-man

    tdi-man Well-Known Member

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    if i pull vacuum pipe of egr dia and seal end of pipe with bolt as a temp measure will that shut egr of ?????





     
  6. a8 tech back

    a8 tech back Member

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    If its only at idle then disconnect the air mass as this will shut egr off but mil will come on
    You can blank the egr to test it but this will put the mil on for egr through put to small
    You mentioned the remap and egr off solution also
    If you just wish to eliminate egr the try either the airmass disconnect or egr blank
    Please note without seeing the problem I must advise you that if its not excessive it may not be a major problem but just the combustion process causing the lumpiness due to egr bounce (dirty air)
    If disabling egr sorts it out then your left with the fact that you will have no N0X regulation and you are polluting the atmosphere.
    I'm not one to preach just highlighting the point
    Let us no how it goes
     
  7. tdi-man

    tdi-man Well-Known Member

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    ok many thanks for that ive been looking for answers to this probelm for ages.

    is egr bounce a common fault ??

    just updating brakes this week then will think about the remap and egr blank of in map.

    i will try air mass disconect over the week end and see what happens.
     
  8. a8 tech back

    a8 tech back Member

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    reading this again I have thought of another possible cause

    So you feel there may be some engine issue?

    We need fuel pressure and max airflow plus throttle position correct fuel and coolant readings as theses are all affected by resistance then any deviation could cause incorrect response

    ie idle at the pedal is 0.5 volt and full throttle is 4.5 volt leaving .5 volt either end for fault recognition feedback

    Possible woffle but throttle pedal readings may be a possible

    As it start first time then the pressure is fine but is the air or throttle response correct

    The throttle position can be reset if I recall also you could check the mvb for throttle position end stops at the accelerator peddle

    so if the pedal readings match in the engine ecu and dsg and the gear recognition is correct check rpm input in the box and this could eliminate engine related problems and highlight the mechatronic rpm input or clutch flare up

    If this is bllocks then ignore me lol
     
    #87 a8 tech back, Apr 5, 2011
    Last edited: Apr 5, 2011
  9. a8 tech back

    a8 tech back Member

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    yes egr bounce is consequential of the process for reintroducing burnt air although the ecu knows its coming into the combustion process its like drinking a nice pint and near the end you get a few floaters lol
     
  10. tdi-man

    tdi-man Well-Known Member

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    another idea is what what happen if you turn the alan key setting up in the tandem pump ?
     
  11. a8 tech back

    a8 tech back Member

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    Lost me there, the only alan key i recall is the port to check the fuel pressure
     
  12. tdi-man

    tdi-man Well-Known Member

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    oh was told you can turn the presure up and down by adjustment on tandem pump ?

    not sure if this would put fueling up ?
     
  13. a8 tech back

    a8 tech back Member

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    not aware of this
     
  14. tdi-man

    tdi-man Well-Known Member

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    ok i will ask chap tomo and post info...
     
  15. chris11122

    chris11122 Member

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    My tick over is getting worse - left work at lunchtime and it was all over the place.

    Left to come home tonight and my tick over raised itself to 1000RPM - weird.
     
  16. gizm0

    gizm0 Member

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    ok guys so ive just replaced the second coolant sensor, the car started fine right untill it got up to full temperature then it struggled again :(. but i noticed that when the climate control is switched off the engine judders really bad, but when i switch it on its perfectly fine and the engine runs like normal. so its confusing me a little now as to what it can be as surely it would be doing it all the time either with or without the climate control on?

    any help appreciated. cheers

    Dan
     
  17. gizm0

    gizm0 Member

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    Ok guys so ive just replaced the second coolant sensor, the car started fine right untill it got up to full temperature then it struggled again :(. would you guys say its a new starter motor now or could it be something else?

    Also i noticed that when the climate control is switched off the engine judders really bad, but when i switch it on its perfectly fine and the engine runs like normal. so its confusing me a little now as to what it can be as surely it would be doing it all the time either with or without the climate control on?

    Any help appreciated. cheers

    Dan
     
  18. a8 tech back

    a8 tech back Member

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    turning the a/c starts a chain of command

    from the top of my head

    a/c signals to j519 then to engine ecu to boost the idle to allow extra load demand and the alternator monitors this via a df signal pulse width modulation to the engine ecu

    adjust the base idle to the higher value

    poor warm starting

    possible cranking rpm below 250 rpm caused by increase wear on the starter or high resistance on the starter cables or battery which in turn stops the injectors opening because the engine ecu does not recive the correct rpm speed

    also poor tandem pump residual pressure

    check with vcds the engine cranking speed when warm
     
  19. gizm0

    gizm0 Member

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    Ok that doesn't mean much to me lol I'm not that technically minded :(.
    What do you think would solve the problem of the rough idling when the aircon is off?

    Would you say replacing the starter motor would fix the struggling to start when hot?
     
  20. gizm0

    gizm0 Member

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    Ok that doesn't mean much to me lol I'm not that technically minded :(.
    What do you think would solve the problem of the rough idling when the aircon is off?

    Would you say replacing the starter motor would fix the struggling to start when hot?
     
  21. NHN

    NHN Retrofitter - Audi - VW - Skoda - Seat
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    I'd go with new/replacement starter for warm issue, usually old starter suffers from heatsoak of the gearbox, as its fairly simple to change, then do yourself, as cost of replacing in labour with audi would be same as the part, I've done both my cars & the difference in starting was vast.

    Now as we're on a forum, we're speculating, so nobody can guarantee your issues are this, but based on fair few others, new starter can only be a positive step anyway.

    Gizmo, before clicking POST again, wait a little bit longer as you keep double posting.
     
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  23. gizm0

    gizm0 Member

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    Yeah I'm just asking on here as I know there's some very kNowledgeable people on here :) and alot of people have had the idling problem so trying to gain from their experience of what solved it.

    Sorry about the double posting I am only clicking it once but I'm viewingon my phone so it must be that.

    How would I adjust the base idle? Is this a proper fix or just a shortcut way out?

    Thanks
     
  24. gizm0

    gizm0 Member

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    ok so i've just fitted a new starter motor in the a3 to try n fix the starting problem and...nothing! :( if anything its got worse :( and obviously its still juddering :'( any more advice please guys?

    thanks in advance
     
  25. NHN

    NHN Retrofitter - Audi - VW - Skoda - Seat
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    Urmmm thats interesting, so ok give us a list of what you've done so far please.
     
  26. gizm0

    gizm0 Member

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    ok....not a lot really but, new injector wiring loom, new coolant temperature sensors and now new starter motor, new fuel filter, cleaned out EGR valve and thats about it i think.... any ideas? :(

    EDIT: oh and a new throttle body

    iv read about it being a the battery? is it worth getting it tested?
     
    #104 gizm0, Apr 26, 2011
    Last edited: Apr 26, 2011
  27. a8 tech back

    a8 tech back Member

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    You really need to confirm the problems with some evidence before replacing things

    I would only replace the starter if the cranking rpm was below 250 rpm and in the knowledge the battery is in order plus the engine /gearbox earth and the starter wire

    You need to check the fuel pressure and also the injectors values

    Also check the fuel for soot

    Using vcds check your measured value blocks 13 for injectors and also try and use the advanced mvb feature so you can see fuel, air and coolant temp at the same time and also air volume and egr

    Also include the valve timing reading

    This will show you what's going on because your description points towards low cranking rpm or insufficient fuel delivery/pressure

    I understand its hard but its even harder to explain from a lap top
     
  28. gizm0

    gizm0 Member

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    ok thanks so how do i get vcds? have you got a link so i can buy it?


    also the fuel was black when the filter was changed so it was flushed to clear it up and its a lot better now
     
  29. gizm0

    gizm0 Member

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    could i have fitted anything wrong on the new starter o anything to have made it stugle?
     
  30. a8 tech back

    a8 tech back Member

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    flushing will only remove the current deposits, you need to establish if there is soot present in the fuel which indicates combustion blow pass from pitted cylinder head injector seats or poorly seated injectors/ seals

    nhn sells vcds
     
  31. NHN

    NHN Retrofitter - Audi - VW - Skoda - Seat
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    Thanks A8, yes I do sell the genuine vcds PM if interested.

    Also if a battery is on the menu, then I suggest an uprated version that audi do supply, Varta Ultra Silver Dynamic, fits the 8P perfectly & certainly better than the stock Varta Blue they fit.
     
    #109 NHN, Apr 26, 2011
    Last edited: Apr 26, 2011
  32. gizm0

    gizm0 Member

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    ....and now the ESP light and the power steering light are on :banghead:
     
  33. NHN

    NHN Retrofitter - Audi - VW - Skoda - Seat
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    TBH A8 is very knowledgable, he's right & I dont want to seem like I'm hunting for a sale, but vcds would be helpful atm for you, considering audi's hourly rates would pay for that in 2-3 hours mate.
     
  34. mike foster

    mike foster Fossie
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    If the battery has been disconnected this is normal. drive for a few hundred yards and they should go off.
     
  35. gizm0

    gizm0 Member

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    I understand, and i know it would be worth it, just didnt really want to spend that kind of money at the moment. Are there any places that test them and get all the stats the Vcds give, (apart from Audi obviously) Better still, anyone local that could test it for me :thumbsup:
     
  36. mike foster

    mike foster Fossie
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    Check the VCDS members list in NHN signature
     
  37. gizm0

    gizm0 Member

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    thats a relief as the battery was disconnected.

    thanks
     
  38. NHN

    NHN Retrofitter - Audi - VW - Skoda - Seat
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    Ah you didnt say you'd disconnected battery yet, lol, good call Mike.

    TBH mate which ever garage you go for diag etc will cost you, yes a local vcds member is great, but what happens when you need to do more tests, without being funny people are nice, but when you need it for a prelonged periods & more than once, its a stretch for allot of people as they're busy with family/work etc, of course most are glad to help, but convenience plays a big role here, as I'm sure Mike & all who own will advise & no waiting for results.
     
  39. hollow

    hollow Active Member

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    when car is sat idling open bonnet is engine juddering ?
    if yes look down towards left side where alternator is just below alternator is a tensioner is this vibrating back and fourth ?
    is yes then the pulley on the end of your alternator is knackered the bearing is seized , this can cause starting problems and the shuddering

    the price is 24 quid including vat from tps , but you need a special spline bit to remove it

    are you in south yorkshire by any chance ?
     
  40. gizm0

    gizm0 Member

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    yeah i understand that, i just cant afford that at the minute so ill have to wait i guess

    just been out to check that and the pulley looks fine...unfortunatly :( lol

    no i'm from b'ham mate
     
  41. mike foster

    mike foster Fossie
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    Have to agree - in the long run you will find that you need/want to use it more and more.

    For a one-off test ask someone by all means but sounds to me like you may need continued VCDS help and diagnosis !
     
  42. hollow

    hollow Active Member

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    dont look at the pulley on the alterator , check the tensioner block just below and to the back of it .

    oil in the fuel means that either the tandem pump is knackered or injector seals are
     

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