Audi A6 2.7 & 3.0 TDi EGR & Intake system cleaning info please...

[gupsterg]

Hi Sparker ...

Honest answer still at this moment in a grey area about if this is the fix... not driven car much other than TD of few miles Sun, Mon 6 miles, today off drive to get@van then replace back...

First start is still the worst fluctuations but less erratic, smoother fluctuations, very little engine noise variation for now that mis-fire noise has gone...

What I do know deffo has changed is cold starts ie 8 hrs or more of standing are so less laboured and still not put new battery in yet ...

Going over the old videos of the MVB 03 for EGR at cold idle the mass air readings were in the region of 100 to 200 mg/stroke out between data 2 & 3...

Now it is amazing difference... below is MVB screen shot after TBA cleaned...


Further tests are going to be done on the EGR valve and cooling flap but like you said taking it easier ...

You guys are my online therapy group and if you asked my wife she'd say I need a lot ...

[Cwizard]

MVB readings.jpg3000rpm.jpg

these are some of my readings... just for the heck of it... :-)

[gupsterg]

Your ECU has specified air mass of 258.5 mg/stroke, actual air mass is 334mg/stroke ...

Ref link:- audi 3.0tdi engine measurement blocks

003 Exhaust gas recirculation
1) Engine speed
At idle: 720 ... 820 rpm
2) Specified intake air mass
[mg/stroke]
3) Actual air mass
[mg/stroke]
4) EGR valve activation
[%]

010 Air quantities
1) Actual air mass
At idle: 210 ... 280 mg/stroke
At full throttle: > 1050 mg/stroke
At ambient air pressure 970 ... 1020 mbar
2) Ambient air pressure
[mbar]
3) Actual charge pressure
At idle: 950 ... 1080 mbar
At full throttle: > 2150 mbar
At ambient air pressure 970 ... 1020 mbar
4) Accelerator pedal position
[%]
- With exhaust gas recirculation switched off, e.g. due to
high intake air temperature the air mass at idle may be increased
In this case press the accelerator in short bursts and check
whether the air mass then decreases.
- Additionally check air mass via basic setting of EGR
and turbocharger basic setting.

Now the text in red above is what used to throw me due to lack experience ...

You can check intake air temp with below MVB...

007 Temperature senders
1) Fuel temperature
to 70 °C
2) Oil temperature
Warmed-up: 70 ... 110 °C
3) Intake air temperature
to 75 °C
4) Coolant temperature
Warmed-up: 70 ... 110 °C

EGR gas has other functions as well as adjusting air mass... google for EGR functions...

I will create PDF of test drive log on Sunday and attach to this post later my air mass reading now follow each other in MVB 03 very closely now...

Post 7 has been updated with cleaning process pic & video...

Currently I believe my EGR valve & cooling flap is working correctly i) because MVB's are good now ii) visual checks done linked below...

Link:- Cooling flap check Link:- EGR valve check

I've done a fresh video for MVB's 03, 10, 22 & BM 01 to 06 this morning at very low temps of below 0c...



Above has been the most laboured start after TBA cleaned, battery still old just fitting new today plus the lowest outside temps... will post pic of car later...

[JimC64]

Awesome work Gup and an excellent post as always, thanks so much for sharing

Subscribed to keep abreast of updates.

[gupsterg]

Hi Sparker,

As always cheers for viewing & comments ...

The old manifolds had no where near as much carbon build up on them as those in the pictures.

Were yours the original ones (lower manifolds)? What was service regime?

As you know mine is 2005 with 80K, "Long Life" servicing previous owners now had 2 in 10K... I've even seen a TSB/TPI advise that better fuel (with additives) & oil prevents engine coking... maybe mine more nasty due to "Long Life" servicing...

Awesome work Gup and an excellent post as always, thanks so much for sharing

Subscribed to keep abreast of updates.

Hi Jim,

Again cheers mate for support ... you may recall that phone conversation before I took car in for "the Chain Job" IIRC you had your reservations/suspicions of level of service that may be provided... now it looks like you were right ...
Well Jim next phase has been planned , when action at present no idea ...



In above image is location of EGR Cooler (Blue box), EGR cooling flap (Turq.box) & EGR Valve (Purple box)...

Below is an image I found on ebay showing the ports in EGR cooler...

no because its a 3.0 tdi and the next fault will be egr cooler

Yes MVB's look good for EGR/Mass air but I think I could nail cleaning this with my mates air compressor... if TBA ports can block these seem smaller...
When I viewed EGR connecting pipe whilst doing TBA it had a sooty dry carbon so fingers cross blast of air should do it or pipe cleaners/homemade tool ...

The EGR cooling flap will also be cleaned or replaced... it looks like the cooling flap has a superseded part but EGR valve & cooler not...

[six_or_out]

Hi Gup,

I had the EGR cooler cleaned by Audi a couple of years ago when they replaced the intake manifold (due to the common failure).

A few weeks ago, I cleaned out the whole intake system (both upper and lower sections), the throttle body adapter and the throttle valve. Similar to yours, the two small holes in the adapter were completely clogged and although its a dirty job, it wasn't particularly difficult to clean.

After cleaning it feels like the car is breathing much easier .

Six.

[gupsterg]

After cleaning it feels like the car is breathing much easier .

x2, mate car really feel so much better to drive... I know it may seem to others that how much better could my car drive considering it now got new injectors (x6), throttle & MAF... plus all chains & tiptronic oil done...

But it is amazing ...

A few weeks ago, I cleaned out the whole intake system (both upper and lower sections), the throttle body adapter and the throttle valve. Similar to yours, the two small holes in the adapter were completely clogged and although its a dirty job, it wasn't particularly difficult to clean.

My lower manifolds are original, so are the swirl motors & links... I'm hoping to do all soon ... how did your original manifolds look like? at that time what mileage? what service regime?

Your the second person (third me ) who said they've cleaned throttle body adapter... seems pretty common then IMO...

ATB
Gup

[six_or_out]

There was only one original manifold, the other was from 2009 (replaced by Audi at 90k miles). To be honest there was very little build up on them compared to your photographs. The original one had a few MM of build-up on the flaps. The one from 2009 had minimal build up on it. I used a foaming degreaser, worked a treat

The car has got 144,000 miles on it now and has been on variable servicing since new.


Six.

[gupsterg]

Another query six_or_out & sparker as I'm trying to understand why my manifold/tba would be so coked up...

So six_or_out as you've been on "Long life" servicing as well that throws that out the mix but my car even if same year as yours half the mileage roughly...

So does this further reinforce that "Long life"=motorway driving/higher miles a year and "Interval"=local/lower miles a year...
My injectors were the very first revision until a month ago (059 130 277 S) now are 059 130 277 BD... Link:- A6/C6 injector PROBLEM - Replacement/refurbished injectors possible?

What are yours? have you had replacement ever?

So sparker yours is 2006 Allroad 3.0 TDi...

What service regime? what mileage swirl manifolds done? injector rev/replacement ever?

Thanks in advance guys for input ...

What mileage have you guys decoked the throttle body adapter? how often?

It may seem like data I don't need but could help fellow V6 owners ...

I have also found a TSB/TPI relating to this coking in the TBA (using my VIN data) so it must be common for them to have this documented!

[sparker]

Hi Gup,

Mine is on "Long Life" but while I have owned the car it does have an oil change every year. Original injectors. Cleaned the throttle body adapter when I did manifolds at about 62,000 miles. The holes where dirty but not blocked. Just a case of the holes being a bit bigger after cleaning than they had looked.

I had thought the EGR valve was for recirculating the gasses that build up in the engine (closed breather system) and stood for Engine Gas Recirculation. Obviously, more recently having read on this site the problems with exhaust gas recirculation I now know what they do.
In any case I would assume that if your injectors where at fault for a while then the exhaust gases would be dirtier, sootier and more contaminated, this would then be recirculating through the system and causing your lava flow looking manifold inners.

Does look like a good clean up of your system would be a good idea but thats more work more hassle!