Eliminate diesel clatter CDUC, CDUD 3.0tdi

[bx3m]

Thanks for the encouragement! I can imagine it's not a farmacy, especially since I have many town trips. Will definitely do it, but maybe not this week, I have just a couple of (full) days then going on vacation for a week. Will be back to post my impressions

 

[AndyT306]

it's this one i cant get out - bottom right

 

[Tommmygunnn]

it's this one i cant get out - bottom right

View attachment 258765

Yep...that one caused me the most trouble too. I think I came in from top down with a torx bit on a small ratchet extension (to get just past the bulk of the stuff in the way), with the ratchet then coming straight up vertically, . I remember having to push some kind of hose out of the way of the ratchet extension at the same time. I could only make like 1mm turns at a time too. Very frustrating but it can be done..with lots of swearing.

 

[AndyT306]

Yep...that one caused me the most trouble too. I think I came in from top down with a torx bit on a small ratchet extension (to get just past the bulk of the stuff in the way), with the ratchet then coming straight up vertically, . I remember having to push some kind of hose out of the way of the ratchet extension at the same time. I could only make like 1mm turns at a time too. Very frustrating but it can be done..with lots of swearing.

i bought the lowest profile ratchet on amazon it's about 2mm thick and i still can't get it down there

 

[Tommmygunnn]

i bought the lowest profile ratchet on amazon it's about 2mm thick and i still can't get it down there

Hmm that's odd. I remember also trying a torx bit on a long semi flexible extension on the end of a screw driver. Maybe that got it loose. I can't remember exactly as I threw so many tools at that thing. With the flexible extension I came in from the front, slightly bending the extension around all the clutter, and turned the screwdriver while keeping the tension on the flexible extension. The flexible extension I had from a small handheld toolkit. I'll send a pic of the type of thing mate.

 

[Tommmygunnn]

Hmm that's odd. I remember also trying a torx bit on a long semi flexible extension on the end of a screw driver. Maybe that got it loose. I can't remember exactly as I threw so many tools at that thing. With the flexible extension I came in from the front, slightly bending the extension around all the clutter, and turned the screwdriver while keeping the tension on the flexible extension. The flexible extension I had from a small handheld toolkit. I'll send a pic of the type of thing mate.

 

[AndyT306]

cheers, i've ordered something similar... will give it a go

 

[AndyT306]

ordered a plastic one... located onto bolt, wouldn't turn (just twisted itself)

 

[AndyT306]

i'm admitted defeat... managed to get a flexhose onto the bolt in question and it just wont turn most be overtight

 

[bx3m]

Hey guys, I tried to do it earlier, but no luck. First, I was afraid to get this one loose:

Next, I was unable to unscrew the 2 torx the hold the plastic from below... Any ideas on HOW to unscrew them? Also, is it safe to loose this metal bracket? Everything else went fine, even the lower back screw, managed to take it out with an articulate extension + flexible extension, easy peasy The flap on the right was pretty clean...

 

[bx3m]

Hey fellas!
Soooo... I had the car at the repair shop the other day, for something else, but taking advantage of this, I asked the guys to also clean the swirl flap....

Oh My God!! It is truly the difference between day and night! The car is quieter, faster in response and I'm not sure about you, but my consumption went down by 2%! Thank you so much for creating and maintaining this post!!

 

[bx3m]

Guys, what the hell did I do? After a few days when all went perfect, couple of days ago I plugged in the OBD11 and let the IMRC open/close run for a few seconds. Now, the consumption went back to as it was before the cleanup I tried to disconnect and reconnect the plug on it, same result. The car runs smooth, no problem there, but the consumption went back to "normal"
P.S. Please don't ask me why I did this, because the answer is simple - because I'm a dumbass... NOTHING was wrong, still I did it (

 

[bx3m]

Anyone know how to reset the IMRC? Or Perhaps the EGR needs a reset of adaptations? How do I do it? Both VCDS and OBD11...

 

[pelhamsdetailing]

When you say consumption, do you mean fuel consumption? If so, your "2% less consumption" is the smallest of margins. That's barely measurable in the real world. Day to day driving will always vary fuel consumption to some degree. Also, if by IMRC you mean the actuators and the swirl flaps they control, if they were not working you would know about it already. You'd have a fault code and limp mode. In fact, their tolerance is particularly strict.

EDIT: When the engine is cold, you can pop the bonnet, switch the ignition on and see / hear the actuators do a range test, where they go from their default position to fully closed, and then back to open again (which is their default position).

 

[bx3m]

Yes, I mean fuel consumption, but by 2% I mean that it went down from ~9% to 7%, during the 98% same driving conditions - I drive every day on the same route to/from work, at the same times, and the driving conditions are "the same". No, there is no limp mode active, it's just that after the cleaning, the mechanic has reset some adaptations, which I believe it would push the consumption up, and by re-adapting to the new, clean swirl flap had the mentioned result. Anyway, I am going to see him this afternoon and he'll do the same as he did when he cleaned the flap, so hopefully I will have the same result. I will keep you updated as to what he did

 

[20v-quattro]

Just completed this clean on my 2016 3.0 BiTDi and it's made a huge difference, didn't remove the flap altogether but took just half out so it still does something!! However I am unable to alter the EGR stroke using my vcds. All I keep getting is 'value out of range' whether I put +35 or -35 in never mind 50 as some have achieved. Any help or step by step procedure for achieving this stroke change appreciated

 

[20v-quattro]

 

[Audidi]

Just completed this clean on my 2016 3.0 BiTDi and it's made a huge difference, didn't remove the flap altogether but took just half out so it still does something!! However I am unable to alter the EGR stroke using my vcds. All I keep getting is 'value out of range' whether I put +35 or -35 in never mind 50 as some have achieved. Any help or step by step procedure for achieving this stroke change appreciated

Worked fine on my bitdi.
I wouldn’t do this if you have a DPF. My bitdi stopped doing Regens with the EGR adjustment.

 

[20v-quattro]

Worked fine on my bitdi.
I wouldn’t do this if you have a DPF. My bitdi stopped doing Regens with the EGR adjustment.

Hi,
Would a lower value, say -10 still allow regens but provide some improvement to the build up again. Or is a clean something I'm going to have to do every 20k miles?!

 

[Audidi]

Hi,
Would a lower value, say -10 still allow regens but provide some improvement to the build up again. Or is a clean something I'm going to have to do every 20k miles?!

Any reduction in the operational angle of the EGR valve should help reduce coking up of the valve but it may not be enough of a benefit to avoid having to clean it. Audi seem to cause the EGR to **** itself after the last recall for Nox issues.

 

[20v-quattro]

Any reduction in the operational angle of the EGR valve should help reduce coking up of the valve but it may not be enough of a benefit to avoid having to clean it. Audi seem to cause the EGR to **** itself after the last recall for Nox issues.

I'm off to see my friendly Audi specialist on Thursday so will see if his proper Audi equipment can adjust this value and see what I can get away with before it affects regens. Thanks for info

 

[bx3m]

@20v-quattro - any news on the EGR adjustment?

 

[20v-quattro]

@20v-quattro - any news on the EGR adjustment?

Still not been able to adjust it. Were later cars stopped from being able to adjust due to the emmisions issue?

 

[bx3m]

That might actually be an issue. My car also has the dieselgate software installed, so perhaps this is the reason why I also cannot adjust this value...

 

[gary_a4_quattro]

Huge shout out to the OP for the information ( and the rest of the Audi-sport community )

My newly acquired Allroad BiTdi started to develop 2 subtle issues;
1) as the the engine was warming up, at the point of approaching’ normal ‘ running 90°C temp, a misfire or uneven rpm experienced at low throttle demand ( eg maintaining 30mph ) also resulting in the gearbox swopping between gears unnecessarily.
2) lack of refinement as mentioned in the other posts , sounding like an old clattery diesel on light acceleration- this went away on higher throttle demands.

As off on holiday today, thought I’d take a quick look after finding this thread yesterday. Image is before cleaning obviously
Considering the relatively low mileage of the car (34K) I was surprised by the dramatic amount of deposits in the swirl flap/inlet runner housing, the short inlet pipe with the EGR return and into the inlet manifold. Due to restricted time available, it was a clean of the swirl flap assembly ( leaving in the butterfly) , accessible bit of the inlet manifold and the delivery inlet.

Outcome: all issues gone, large increase in refinement, low down lag improved. Probably the most rewarding hour I’ve spent on a car in a long while !

Finally for those who’ve found a challenge to get to some of the more awkward position screws, this little set from tool company Bahco has help me on some many occasions:

Bahco 2058/S26 1/4" Drive Ratchet and Socket Set 26 Pcs

Bahco 2058/S26 1/4" Drive Ratchet and Socket Set 26 Pcs The Bahco 2058/S26 is a compact, pocket sized socket bit set with 26 pieces. Contains 18 different types of bits and 5 small sockets ranging from 6 - 13mm. The set is supplied in a plastic carry case with sponged lining that is labelled...

www.powertoolworld.co.uk

Others styles of this set are available, Bosch do a similar iirc , but can only comment on how robust the Bahco set is for such a small tool. Obviously it’s not gonna undo a seized M10 bolt, but those awkward to get to jobs, it’s been great.

will update if I decide to take the inlet manifold off for a proper clean and see how much crap there is around the inlet valves etc……

 

[Oggie]

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

Hi
Massive thanks for the initial post, an invaluable bit of information to what seems to be an issue we are all facing.
Unfortunately I came across it a little late in my diagnosis flow chart.
I have a 2013 a6 c7 bitdi and had already cleaned the flap motor and got some improvement but several months later the problem returned. I tried unplugging the flap motor and was amazed to find how smoothly the car ran but after a day the orange eml came on.
This identified the problem part so I’ve purchased a secondhand part to see if this resolves things.
Does anyone know if any settings will need altering when fitting this secondhand part?

 

[J10NMM]

what about something similar for the 2.0TDI

 

[pelhamsdetailing]

Hi
Massive thanks for the initial post, an invaluable bit of information to what seems to be an issue we are all facing.
Unfortunately I came across it a little late in my diagnosis flow chart.
I have a 2013 a6 c7 bitdi and had already cleaned the flap motor and got some improvement but several months later the problem returned. I tried unplugging the flap motor and was amazed to find how smoothly the car ran but after a day the orange eml came on.
This identified the problem part so I’ve purchased a secondhand part to see if this resolves things.
Does anyone know if any settings will need altering when fitting this secondhand part?

I personally did not need to calibrate it or have a part that was calibrated out of the factory. Plug and play, and was important that I fitted it electronically and mechanically, and then test it. If I tested it plugged in but not mechanically fitted, it wouldn't operate properly and act as if it was jammed. It was bought on ebay, new, based on the part number. My car was a 2007 A5 3.0TDI (CAPA) with an older ECU firmware.