1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Dismiss Notice

Eliminate diesel clatter CDUC, CDUD 3.0tdi

Leighspain1975 Nov 4, 2018

  1. Leighspain1975

    Leighspain1975 Member

    65
    5
    8
    Hi All
    Thought I’d share this with you in case it helps someone......
    Has any 3.0tdi CDUC, CDUD owners who have higher mileage engines notice a more pronounced diesel clatter noise at idle or at low rpm and maybe notice the engine isn’t quite as smooth in low rpm as it used to be ?.
    Here may be your solution?.

    I was desperate to find the solution to this issue and did everything, new injectors, Maf, egr and Dpf cleaning. None of these really worked and it annoyed me that such a nice engine wasn’t as refined as it should be.

    By pure fluke I found the answer in 2 words “Swirl Flap”.....

    Bear in mind that the older 3.0tdi engines has swirl flaps in the intake manifold. The 2nd gen engines don’t. It has one large motorised swirl flap before the manifold with two holes. One for EGR return and other for fresh air. The fresh air hole has a butterfly valve which opens and closes but mainly it’s a low rpm when it’s used to swirl the air into the intake.
    These things fail and can do so without any warning light or error codes. The flap which gets built up with carbon may not be opening properly literally starving the engine of fresh air and too much EGR gases.

    Quick solution is remove the part and remove the butterfly valve, it’s only two screws and the rod can be left in situ so no error codes are thrown when plugged back in.

    Before removing the butterfly valve you can make a quick test. Unlock car open the bonnet, close the door and lock the car. Leave for a minute and disconnect the sensor/motor. The flap will now be fully open and you can test for yourselves if it improves the drivability of the car. It will eventually throw an error code and your Dpf may not regen as a result so if it’s improved I would suggest you remove the butterfly valve.

    You may notice at first that the car pulls away a bit more sluggish than normal but the ecu will rectify this after a few 100kms.

    The second part was to connect VCDS....
    Go to Engine - Adaptation - EGR Correction

    Select 35 mg/stroke as new value. Old value should be 0mg/stroke. This will close the EGR valve more and effectively tells the Maf to read higher fresh air intake you will probably see around 350mg/ stroke at idle with this adaptation. It’s within the parameters of the ECU so no harm will be done.

    Guys give it a try if you think your engine is sounding a bit clattery.
    Would be good to get some feedback if you try this yourselves.

    Cheers
     
    -Ju-, Bobt and martinivw like this.
  2. Avatar

    snack-media
    Advertisement


  3. Daniel J.

    Daniel J. New Member

    7
    0
    1
    I will try this weekend :) My CDUC behaves kinda clattery in cold weather these days, in low RPM and kinda low demands of power. I will report :) First I thought it could be bad DMF, but I have not found a single thread about anyone having a DMF worn out on these newer 3.0 TDIs, mine is only around 70k miles… And this actually makes sense.
     
  4. Leighspain1975

    Leighspain1975 Member

    65
    5
    8
    Yeah,
    Mines be fine since. Wouldn’t say any increase in power but the engine definitely sounds more refined.
    Remember when you do it.... the butterfly will naturally be half open when the engine is off and you can’t get to the screws.
    Disconnect first and then plug in and switch on ignition. The butterfly will move to a closed position and you can then get to the screws.
    Don’t force the butterfly.

    Cheers
     
  5. Daniel J.

    Daniel J. New Member

    7
    0
    1
    IMG_5753.JPG

    Hi,

    I will ask additional questions, I am not native so I need to make sure I understood your description. In the attached Picture - is the description ok? Is the part on the left the motorised swirl flap thing? If so, to test it, I should disconnect the connector on the side of it? If so, I would like to first test it out. So the procedure should be - unlock the car, open the bonnet, close doors, lock the car, wait a few minutes, disconnect the connector on the side of swirl flap housing, start the car and try out? What does not make sense, since you mention the natural position is half open, how can it fully open when disconnected?

    If the test will be ok, the ride improves, then I should remove the black tuby thing and unscrew the flap plate on two screws, let the rod there and connect the housing to the connector again?

    Sorry again :)

    Thank you,

    DJ
     
  6. Leighspain1975

    Leighspain1975 Member

    65
    5
    8
    Exactly correct

    Unlock car, open Bonnet ( Hood ) , close door, lock car, wait a few mins and the. Disconnect.

    Remember.
    Half open is actually fully open. The flap will rotate 90 degrees to fully open position. So the flap will be horizontal and letting full air into the car.

    If you decide to remove completely you’ll need to do what I said before. But the testing is very easy to do first.

    Let me know the results

    Thanks
     
  7. Daniel J.

    Daniel J. New Member

    7
    0
    1
    Ah, fine. I thought half open means like 45 degrees. This explains everything.

    This actually looks pretty damn easy.
     
  8. Leighspain1975

    Leighspain1975 Member

    65
    5
    8
    Yeah it’s a piece of cake to try it out.

    Drive the car a little while too to allow the fuel / air adjustments to take place too. It may start a little lazy but while suddenly pick up and run much better.

    I also find the engine idles much better too. The engine sounds more happy.
     
  9. Rhyso

    Rhyso Well-Known Member

    1,791
    470
    83
    [​IMG]

    [​IMG]
     
  10. Leighspain1975

    Leighspain1975 Member

    65
    5
    8
    Mine looked the same. Filthy and clogged but I think the motor in mine wasn’t opening properly either.
    Amazing to think all this filth comes from the Egr return.

    I have closed my EGR to minimal allowable settings.

    Vcds UDS protocol ....

    Select Engine, Adaptations, EGR Correction. Should be at 0.0mg reduced mine to -50mg
     
  11. Rhyso

    Rhyso Well-Known Member

    1,791
    470
    83
    Mine is mapped out via my remap :D
     
  12. Avatar

    snack-media
    Advertisement


  13. desertstorm

    desertstorm Moderator Staff Member Moderator VCDS Map User TDi quattro Audi A4 Audi Avant Owner Group

    7,226
    3,577
    113
    Makes you wonder why they bother with an air filter TBH when they are recirculating so much stuff back into the engine.
     
  14. Leighspain1975

    Leighspain1975 Member

    65
    5
    8
    Why would mine better when the DPF is regenerating?.
    I know it’s doing it because the fans switch on.
    It’s such a big difference too the engine will run quieter, be more responsive and it’s so much smoother.

    Can’t figure it out
     
  15. Leighspain1975

    Leighspain1975 Member

    65
    5
    8
    After the regeneration it goes back to its noisy bumpy self ?.
     
  16. Daniel J.

    Daniel J. New Member

    7
    0
    1
    Hi guys!

    So I tested it out (disconnected the connector, drive around for like 40 miles), I did not notice any difference, so I decided to let it be. I did not even disassamble the intake to clean it, I felt like too lazy this weekend :D

    But thank you for advice anyway!

    DJ
     
  17. Bobt

    Bobt Member VCDS Map User Audi SQ5 Owners Group

    64
    1
    8

    I know this is an old thread but wanted to say thanks for the info, this has made a night and day difference to my SQ, waiting for vag-com lead so I can dial out a bit of the egr sludge
     

    Attached Files:

  18. jetty

    jetty Active Member Team V6 quattro Audi A6 Audi Avant Owner Group Black Edition S-line owners group

    255
    72
    28
    Thanks for reviving this thread Bobt!
    Decided to give it a go over the weekend (seen as Audi spent over a year diagnosing clatter/flutter!)
    Gave it a good clean and installed in the fully open position and unplugged. It almost sounded like a petrol!
    Plugged back in and now runs like a tractor - albeit not as loud as before, so the clean has helped.

    I will probably remove the flap/valve. Tempting to blank off EGR now that I've seen the rubbish going back through the engine....possible MOT problems with that I suppose....

    52k on the clock - CVUA engine.
    IMG_2423.jpg
     
  19. Leighspain1975

    Leighspain1975 Member

    65
    5
    8
    My Pleasure it’s helped.

    it just takes the edge of that clattery vag diésel sound and makes it a little smoother.

    Dont- map out the EGR or put a blanking plate. I tried it with mine and it sounded awful and loss of power too.
    The EGR does help when it’s working properly. But you can use vag to close it of slightly that also helps.

    plus with yours, you’ve got active sound no ?.
    I strongly suggest you get the Cete Automotive sound module. It sound awesome.
     
  20. Leighspain1975

    Leighspain1975 Member

    65
    5
    8
    When you disconnect with the flap fully open it will try and compensate the Maf. Removing the flap and keeping connected will trick the ecu as it thinks it’s still there.
     
  21. Bobt

    Bobt Member VCDS Map User Audi SQ5 Owners Group

    64
    1
    8
    Same as yours mine is so smooth with it disconnected but still has noise when connected, initially after cleaning it was very very quiet but has got more noisy. I think it has to be the flap motor not operating the butterfly correctly
     
  22. Bobt

    Bobt Member VCDS Map User Audi SQ5 Owners Group

    64
    1
    8
    Firstly thanks for the info
    when disconnected engine is silent for a diesel but im still getting noise when connected after cleaning which has returned gradually after the clean so im going to remove the butterfly to see if that cures it. Do you think removing the butterfly will effect DPF regeneration or are they any other negative effects of doing this?
     
  23. Leighspain1975

    Leighspain1975 Member

    65
    5
    8
    When you think about it this butterfly flap can cause a world of problems. The sensor is only working based on throttle position and it’s the last sensor before the intake manifold. The ecu has already calculated air and pressure through the Maf and boost sensor and if this is clogged up theirs not enough air but the ecu thinks it’s fine.

    this is why I felt we were getting more clatter and it’s probably due to pinging.

    do you notice the injectors pinging when accelerating and the windows open?. You can hear the sound pinging of buildings and walls.

    however when the Dpf is regenerating you won’t notice it as much because the timing is slightly retarded and actually sounds smoother when regenerating.

    just my two cents.
     
  24. Bobt

    Bobt Member VCDS Map User Audi SQ5 Owners Group

    64
    1
    8
    I was looking at it today and was thinking the same, i went ahead and removed the flap and noise gone while plugged in ! yes i could hear the noise only at low RPM. Yes was quieter during regen and that does make sense why. Thanks again for your two cents im so pleased noise has gone, im still waiting for my VCDS lead to adjust the EGR im also going to look at catch can options
     
  25. Leighspain1975

    Leighspain1975 Member

    65
    5
    8
    Just a quick question...

    Are your injectors Loud?.
    What I mean is when you drive with the window open can you hear the injectors rebounding off walls and buildings ?.
    I had my injectors change a few months ago and it didn’t change the sound at all.
    The weird thing is that when the car is regenerating the Dpf the injector knocking disappears.
    I’m assuming this is probably due to timing being retarded slightly.
    But the noise drives me nuts. Hope it’s not just me....
    Audi and everyone else say it’s normal ..
     
  26. -Ju-

    -Ju- Well-Known Member Team Floret Silver SQ5 owners group VCDS Map User

    3,424
    1,279
    113
    I'm glad I stumbled on this thread as I've thought for a while my 2015 SQ5 has sounded rather more diesel like than I remember at low setting off rpm from time to time. It's actually started to annoy me.
    I'll have a look at the valve tomorrow if I get chance.

    Sent from my SM-N960F using Tapatalk
     
  27. Bobt

    Bobt Member VCDS Map User Audi SQ5 Owners Group

    64
    1
    8
    I did have some injector noise which I sorted by replacing the copper seals,orings and stretch bolts, were your bolts replaced when your injectors were changed ? Were the injectors new or reconditioned.

    Audi said my noise was normal on a health check obviously wasn't because it's sorted now. Are you sure it's an injector and not follower's ?
     
  28. -Ju-

    -Ju- Well-Known Member Team Floret Silver SQ5 owners group VCDS Map User

    3,424
    1,279
    113
    So I took the intake hose off this morning to be greeted with this
    20200525_101340_copy_2268x3024.jpg
    Not very pretty!
    The cars done just over 37k and I thought I was going nad thinking the car was more rattly than I remember.
    So I removed the EGR flap housing and gave it a good clean
    20200525_103458_copy_2268x3024.jpg
    First impressions are night and day different from a quick drive around the block and it's back to how I remembered.
    I know its an old thread but cheers OP for the heads up:icon thumright:
     
    Rhyso likes this.
  29. jbmercapple

    jbmercapple New Member

    7
    2
    3
    I'm going to check my A6 Bitdi. It runs fine but I do think it sound slightly more "dieselly" when I back it out of the garage. Just a quick question, did you have to fit a new gasket / seal, or could you just reuse the old ones?
     
  30. Bobt

    Bobt Member VCDS Map User Audi SQ5 Owners Group

    64
    1
    8
    I'm starting to think it's not just the build up causing the noise ! It's the butterfly motor which isn't operating
    Just clean old gasket and reuse, that's what I did and was fine
     
  31. Bobt

    Bobt Member VCDS Map User Audi SQ5 Owners Group

    64
    1
    8
    My Hex-V2 lead came today so I tried to do this but any change I try to do comes back with error (request out of range)! Can you tell me the method you used
     

Share This Page

Do Not Sell My Personal Information