Eliminate diesel clatter CDUC, CDUD 3.0tdi

+robster+a7+tdi

Registered User
an obd eleven view for folk not familiar
i used output test imrc to sweep the valve shut then disconnected the plug before it went to open again ( 15 secs open / 15 secs closed/ repeat)
then refitted and cleared code after it was cleaned and flap removed -- all good

also egr correction i changed via adaptations i think ( cant mind)
Menu LI
Egr correction changed
Sub menu LI
Submenu1 LI
Egr correction
Menu LI Egr correction changed Sub menu LI Submenu1 LI Egr correction just seen these on my phone tonight but did the job a couple weeks ago maybey it was basic settings
 
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sspt41877

Registered User
there is a locating peg on left at swirl flap motor mount, also underneat there is a bracket mount torx screw just on right of egr metal flange

Yes as above, once the jubilee clip is moved out of the way you can get access to it down the right hand side.
Just to add the car sounds sooo much smoother and more responsive now, if it wasn't for this thread I'd never have known :icon thumright:

Thank you both. I'll have another go tomorrow.
 

sspt41877

Registered User
Managed to get the black pipe off and the swirl flap housing and plastic pipework were all caked in the black stuff. All cleaned off and also decided to remove the butterfly flap before reassembly. The car definitely seems to run quieter, smoother and more responsively. My car's a 2012 model with 112k. Thank you OP :icon thumright:

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fourwhls

New Member
I cleaned all the sludge out of my intake yesterday. I drove it this morning and something is not right.

It drove great for a few blocks, then something went wrong. It's now barely idling and the RPM is surging. It I touch the throttle, it falls on it's face and dies. It's dumping fuel. Cloud of smoke when I apply any throttle.

Should I need to re-calibrate anything after this cleaning? Mine was pretty well clogged, but not any worse than the pictures in this thread.

I had to drive the Q7 back to the house and grab another vehicle and get to work. Just looking for things to look at when I get home this evening.
 

RussJ

Registered User
Check that you've reconnected all the plugs and there aren't any air leaks. Mine didn't need any recalibration.
 

Leighspain1975

Registered User
Sounds like your lacking air.

have you made sure all connectors have been connected back Correctly ?.
Anything blocking intake ?. Rag or something ?

do you have VCDS ?.
 

fourwhls

New Member
Sounds like your lacking air.

have you made sure all connectors have been connected back Correctly ?.
Anything blocking intake ?. Rag or something ?

do you have VCDS ?.

I think so, but I'll double check when I get home this evening. Only connectors I remember disconnecting was the TPS and Swirl valve motor.

I don't have VCDS, but I do have OBDeleven
 

fourwhls

New Member
Just had my wife shoot me a picture of the engine bay and I saw what I did wrong. I forgot to tighten the clamp on the hose pre-throttle body. As soon as the turbo went into boost, it blew it off. This will be an easy fix.
 

Leighspain1975

Registered User
That’s fine with Obd11
run a scan and you’ll probably get errors for the TPS and swirl flap Valve. clear the faults and switch Car off and On again and check faults again.
If nothing appears start car and check engine.
Only thing I can think of is you haven’t connected TPS connector properly. If that’s stuck shut or partially closed it will cause the problems you are describing.
 

Leighspain1975

Registered User
With the swirl flap valve disconnected you will certainly see a higher Maf value because if you disconnect with the engine running you’ll here the EGR shut. To be honest I didn’t notice much difference mapping out the EGR less power if anything. But that swirl flap can cause all types of clatter.
 

mikeav6

Registered User
I planning to do this in the next week or so as I tried it but didn’t have the right tools to get access to all the bolts. However, i have tried disconnecting the swirl flap connector and it is incredible how much quieter it is. Other than a potential check engine light, would leaving it disconnected for a week or two matter until I remove the butterfly?

Can’t see why it would affect DPF as this is based on how full it is and whether it is hot enough to regen isn’t it?


Sent from my iPhone using Tapatalk
 

Leighspain1975

Registered User
The only consequence this will have will be the EGR being shut off. The car will run great but you may have issues with DPF regeneration because the engine senses a fault.
 

Leighspain1975

Registered User
Dpf needs MAF readings and EGR readings to be correct to initiate a regen.
With the swirl connector removed it will cause higher Maf reading because the EGR will be shut off.
 

mikeav6

Registered User
Thanks - why would the EGR be shut off ? When it senses a fault with the Swirl Flap does it close the EGR?


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Leighspain1975

Registered User
They are all connected in a computer sense. Removing the swirl connector increases the MAF reading which in turn will create an EGR error forcing it to stay shut 100% of the time
 

Leighspain1975

Registered User
Removing only the butterfly valve tricks the computer that the Maf is running fine leaving the EGR to function.

but leaving it for a few days won’t cause any major issues and the Dpf will know it needs to regen once it’s all connected again
 

mikeav6

Registered User
Ok great. Think its probably best to suffer the noise for another week or so then rather than risk damage. Appreciate the insight


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damyan90

New Member
Hey, I found this topic by accident but it actually helped me with loss of power diagnosis.
I own 2014 bitdi and had a look last week into the swirl flap and had to clean it of course. It has original 120k kms and it looked like never cleaned before.
After that the car felt lighter, power came back and noise was definitely lower.
Today I again heard the loud noise and had a problem with power on low rpms. Disconnected the flaps and sound is back to normal. Little less power but the ECU has to adjust I guess?

If I understand correctly:
1) Removing the flap mechanically and leaving the connector ON is fine
2) Adjusting EGR values with VCDS is just an additional thing which might help with all the "dust" going back into the engine and the intake manifold?
3) My swirl flaps are basically broken since from time to time they block themselves causing the issue with power and generating higher rattling noise?
4) Isn't that all connected with the software upgrade after the VAG dieselgate? I found such info on Polish FB group that people started observing much higher engine noise after the service software upgrades at Audi's and coming back to the previous version of it solves all the arrised issues.
 

+robster+a7+tdi

Registered User
Ive been lucky and never heard the "clatter" and loss of power which i guess is this flap being partially or totaly jammed / failed shut and suffocating the air intake to say what looks like a 60% inlet restriction and forcing the remaining 40% inlet diameter available through the tangenial inlet path or swirly bob port whatever blah blah for the whole of the rev range where fuel timing and IQ are changed to suit the opening ( which doesnt happen ) so basically its suffocated and all out of whack??

The main reason i removed mine was to see if i could get a bit more induction noise to compliment my k&n filter and my muffler delete but car still sounds stock unless it (very rarely) goes into dpf regen where it gives a nice exhaust note.... so trial and error on the cheap really

Been running mine for over a year now with the runner control flap removed but put it back together yesterday
pictures show the results in about 14 months use.
Not major mileage (5k)as this is a second car but like to put the foot down when using it , its still pretty clean / just a light misting of oil from the pcv return into engine....no excess soot from egr mixed through that is a credit to offsetting the egr stroke settings from my obdeleven

All back together i have noticed better low down torque with this fitted as it was intended from factory in my opinion so i am happy knowing it is clean and fault free back to factory spec

i would probably remove it again temporarily if the motor went faulty saving me a few quid until i could be ***** replacing it. But by looking at the built up soot blockage on some of these members pictures i would hazard a guess that is the reason they jam / fail

pictures are of strip down before cleaning and refitting flap.
20 minute job to take apart and refit on a yearly basis if needing cleaned
 

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Alwayslate

New Member
Just cleaned and removed my flap also. Shout out to the original OP who posted this!

I've done the disconnect test and I really noticed a reduction in clatter in low RPM. So proceeded to take off and clean. However now that it's all back in with the Flap removed, I find that it is not as refined as when I did the disconnect test!

I'm thinking it could be related to the EGR valve itself, as from what I've picked from other posts is that disconnecting the swirl motor actually also shuts off the EGR. So planning to do another disconnect test to see if it runs as quiet as it did with the first test. If it runs better again then I guess I need to do something about the EGR, I don't have VCDS/OBD11 as of yet.

Another possibility and question is how tight should the EGR clamp be? I've done it as in attached photos but wonder if that is too tight/loose?

And lastly, I've managed to shear off two of the small torx screws that hold the motor housing and wondering if that is an issue now? Photos attached.

Now I'm actually thinking of just selling the car and buying a petrol for an actually smooth engine!
 

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Audidi

Useful idiot
Want to test this 50mg/stroke on the EGR on my bitdi.
It should be -50 or 50 to close the EGR more?
 
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Alwayslate

New Member
Ive been lucky and never heard the "clatter" and loss of power which i guess is this flap being partially or totaly jammed / failed shut and suffocating the air intake to say what looks like a 60% inlet restriction and forcing the remaining 40% inlet diameter available through the tangenial inlet path or swirly bob port whatever blah blah for the whole of the rev range where fuel timing and IQ are changed to suit the opening ( which doesnt happen ) so basically its suffocated and all out of whack??

The main reason i removed mine was to see if i could get a bit more induction noise to compliment my k&n filter and my muffler delete but car still sounds stock unless it (very rarely) goes into dpf regen where it gives a nice exhaust note.... so trial and error on the cheap really

Been running mine for over a year now with the runner control flap removed but put it back together yesterday
pictures show the results in about 14 months use.
Not major mileage (5k)as this is a second car but like to put the foot down when using it , its still pretty clean / just a light misting of oil from the pcv return into engine....no excess soot from egr mixed through that is a credit to offsetting the egr stroke settings from my obdeleven

All back together i have noticed better low down torque with this fitted as it was intended from factory in my opinion so i am happy knowing it is clean and fault free back to factory spec

i would probably remove it again temporarily if the motor went faulty saving me a few quid until i could be ***** replacing it. But by looking at the built up soot blockage on some of these members pictures i would hazard a guess that is the reason they jam / fail

pictures are of strip down before cleaning and refitting flap.
20 minute job to take apart and refit on a yearly basis if needing cleaned
Nice work, any chance you could let me know how tight should the EGR clamp be when installed? I've done it as in attached but not sure if that's too tight or too loose? Thanks.
 

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Audi Bremer

Audi A6 C7 4G 3.0 TDI CDUC 326hp 750 NM Stage 2
Just did this on my 37k 2015 SQ5. I'd guess it was 50% clogged up. Surprised how soft and easy it was to clean off with a bit of carb cleaner and an old scraper. I wondered if the plastic inlet manifold was also affected? Has anyone gone the whole hog and checked this out as well?
yeah I did it last night. Just wanted to chek the EGR but when i'll looked with the flashlight into the intake manifold it was also clogged in there :/ So I took the intake manifold of and cleaned it. Also did the swirl flap delete, runs also smoother and much better idle.
 

AndyT306

Moderator
Staff member
Moderator
I need to have a go at this, just ordered a long allen key T30 to get that 4th bolt out at the back!
 

Audidi

Useful idiot
I reverted the changes I made to reduce the operation of the EGR. It does reduce the amount of regens. Not good if you do short runs.
 

AndyT306

Moderator
Staff member
Moderator
attempted to do this a couple of days ago, can anyone help in how in god's name you remove the far bottom bolt from the swirl flap housing? I can't get in there with anything
 

nothingness

Welcome to the layer cake, son

MattyV5

Registered User
what are peoples thoughts on this sound? It’s an A7 but pretty sure they are the same engine? (I posted in A7 forum but not sure that’s as readily viewed as the A6 forum) hope that’s ok!

 
attempted to do this a couple of days ago, can anyone help in how in god's name you remove the far bottom bolt from the swirl flap housing? I can't get in there with anything
It is a little tricky. I'll be looking at this on Saturday, I might take a few pictures. Before I tackle it for real I thought I would make sure I could get to all the screws with the tools I have. I had to cut down an allen key to slacken that particular screw. The rest seem straight forward.
 

ixiux

New Member
One of the best post ever found. Not easiest one to find on google :)
The car 2013 Audi A6 C7 Avant 3.0 TDI 230 kw (biTDI CGQB).
Symptoms: when idling and accelerating on cold engine misfire starts when revs go up. On warm engine this symptom disappears. Also misfire happen time by time when cruising on low rpm. Sometime engine misfiring when gear goes up.
All injectors was tested and one restored. When it not helped started to think about air supply and EGR problems. After plans to delete DPF and EGR tryed last call to google something less radical and BINGO - this post :)
Two hours of dirty hand work and all problems disappeared. Engine runs smooth now. I chose to clean a swirl flap and intake pipes and delete flap. Made no correction on EGR adaptations because all cleaning process are very simple to repeat after couple of years.
Thanks for this solution because it saves a lot of money and time of problem research.
 

Lexi_R

Registered User
Hey, old thread but new problem for me. As I read, everyone succeeded, but I've been sitting on the problem for 1 hour and I can't solve it.
Can someone explain how the screw on the LEFT was removed? There's no way I can access it. Everything else went easily of course, but it looks like I can assemble it without cleaning :)

Screw
 

YorkieTom

Registered User
.What a pig of a job that was, very messy and awkward but what a difference it has just made. Removed and cleaned, kept butterfly valve in place and car feels much happier. Feels much smoother through the range, quieter and feels quicker at low RPM. Some may be placebo but definitely feels like a nice improvement.

I accidentilly snap the oil dipstick guide right at the end after everything was back in place. Is this an easy part to replace as other models they usually twist or snap into place. If anyone has a part number for C7. 5 bitdi that would be great.
 

AndyT306

Moderator
Staff member
Moderator
.What a pig of a job that was, very messy and awkward but what a difference it has just made. Removed and cleaned, kept butterfly valve in place and car feels much happier. Feels much smoother through the range, quieter and feels quicker at low RPM. Some may be placebo but definitely feels like a nice improvement.

I accidentilly snap the oil dipstick guide right at the end after everything was back in place. Is this an easy part to replace as other models they usually twist or snap into place. If anyone has a part number for C7. 5 bitdi that would be great.

any chance you could show me which tools you used to remove the bottom back bolt?

submit a parts request on here to Crewe Audi, they'll help you find the part number
 

YorkieTom

Registered User
I used a few different tools all just using a torx bit. Mainly a small ratchet with torx bit, plus sometimes little extensions to reach some bolts. One or two I used a straight screwdriver with torx bit. Not sure which bolt you mean exactly, but lastly I removed the two bolts holding the EGR pipe at the left side to remove the entire EGR, rather than trying to remove the two bolts at the right as one seems impossible to get to. Feel free to send photo of the bolt if you're stuck.
 

bx3m

New Member
One of the best post ever found. Not easiest one to find on google :)
The car 2013 Audi A6 C7 Avant 3.0 TDI 230 kw (biTDI CGQB).
Symptoms: when idling and accelerating on cold engine misfire starts when revs go up. On warm engine this symptom disappears. Also misfire happen time by time when cruising on low rpm. Sometime engine misfiring when gear goes up.
All injectors was tested and one restored. When it not helped started to think about air supply and EGR problems. After plans to delete DPF and EGR tryed last call to google something less radical and BINGO - this post :)
Two hours of dirty hand work and all problems disappeared. Engine runs smooth now. I chose to clean a swirl flap and intake pipes and delete flap. Made no correction on EGR adaptations because all cleaning process are very simple to repeat after couple of years.
Thanks for this solution because it saves a lot of money and time of problem research.
Hey! Got the same engine, found this topic and thinking of doing the same, even though I don't have any of your symptons, but just as preventive work. Any special issues during the process? Why did you remove the flap entirely?
 

YorkieTom

Registered User
Hey! Got the same engine, found this topic and thinking of doing the same, even though I don't have any of your symptons, but just as preventive work. Any special issues during the process? Why did you remove the flap entirely?
I did mine last week without really having the symptoms. Just over 100k miles and it was all pretty clogged up so clean as many of the parts as you can get to. Its a very messy job but cleans up easy enough with carb cleaner, toothbrush and flathead screwdriver etc. The car definitely responds much smoother at low rpms and generally feels more responsive so worth doing for sure. Most difficult bit is just getting to some of the bolts but I did it with basic ratchet and torx bits.
 
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