A6 3.0TDI fuel tank question - Audi Forums
Audi Forum Audi Forum

Auto Insurance

» Featured Product
Wheel & Tire Center

Go Back   Audi Forums > Audi Models > Audi A6, RS6, S6 and 100 Forum > C6 Forum
Register Home Forums Active Topics Gallery / Showroom Auto Loans Garage Search Today's Posts Mark Forums Read Auto Escrow

C6 Forum 2005+ Audi A6, Audi RS6 & Audi S6 (Audi A6 Forum, Audi RS6 Forum, Audi S6 Forum)

Audi-Forums.com is the premier Audi Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old 08-19-2008, 05:39 AM   #1 (permalink)
Newbie
 
Join Date: May 2008
Posts: 13
Gallery: (0)
tecman is on a distinguished road
Default A6 3.0TDI fuel tank question

Hi,

I need to confirm whether this is a problem or not. Let me describe my concern.
I was traveling a lot for last 2 weeks (5000 km) across the Europe and during refueling I spotted following thing.

1. When fuel tank meter was at "red" on R letter, I could put 58 liters of diesel into the tank, when fuel pump stopped for the first time. Fuel computer was showing 0 km on tank when refueling. After refueling, fuel tank gauge doesn't align with "F" (1-2 mm away from F mark), and after 20-30km of motorway driving at 130km/h constant speed, it drops between 3/4 and F marks.
2. Same situation but this time, I'm trying to squeeze as much fuel as possible after first fuel pump stop. I'm able to put 10 liters of fuel more, which ends at 68-70 liters. This time fuel tank gauge goes 1mm past F mark and it will stay around this mark for 80-110km since refueling.

As far as I'm aware, A6 3.0 TDI are equipped with 80 liters fuel tank as standard? Mine car is 2005 - UK specs. If that's correct, why I'm able to fill 60 liters even the fuel gauge says the tank is dry?! I can fill up to 70 liters but fuel pump stops every 0.5-1 liter I tried to put above 60 liters mark?!

Have anyone noticed same thing with their A6 cars with 80L tank?

Regards,
Tecman
__________________
Audi A6 Avant (4F) 2005 UK spec
3.0 TDi Quattro
Retrofitted: Anti-dazzle rear view mirror, DVD Navi, APS+
tecman is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 08-19-2008, 03:46 PM   #2 (permalink)
Newbie
 
Join Date: Apr 2008
Posts: 17
Gallery: (0)
gtiller is on a distinguished road
Smile

Hello Tecman!

Sure enough, the A6 has an 80 litre tank (see attached spec sheet)

When my DIS says Zero Miles - I can only ever get 70 litres into my tank.


... I remember seeing a switch somewhere in VAG-COM saying 70 litre tank, and I am wondering if both yourself and I have the wrong setting, so DIS is telling us we need to refuel too early.


I need to check mine (which I won't be able to do until the weekend unfortunately)


Same as you - the fuel pump at the garage cuts out after about a 60 litre delivery. I have found that this isn't so bad if I pump the fuel slower rather than flat-out.

I have also found that withdrawing the nozzle very slightly makes it easier too.


Regarding the fuel gauge accuracy, I have found that all Audis are bad in this respect (my current Audi is my third one)
Half a tank down on the fuel gauge after a long drive, and I can squeeze between 45 and 50 litres of fuel in. You would expect nearer to 35 litres!

I can only assume this is because the tank is not perfectly square in shape (so the guage is not totally accurate, as the level in the tank goes down) and also that there must be some kind of issue with venting/vacuum in the tank.


I'll let you know my VAG-COM findings... unless you get to your first
Attached Files
File Type: pdf A6 Avant 3.0 TDI quattro Tech Data UK.pdf (54.8 KB, 250 views)
gtiller is offline   Reply With Quote
Old 08-19-2008, 04:02 PM   #3 (permalink)
Newbie
 
Join Date: Apr 2008
Posts: 17
Gallery: (0)
gtiller is on a distinguished road
Default

Just been moochig through the Ross Tech Wiki

17 Instrument Cluster


Coding
????***: Options
+0001 = Quattro (Standard)
+0002 = w/o Driver Information System (DIS)
+0004 = Vehicle with Clutch (NO Automatic)
+0008 = Second Tire Size Pair
+0016 = Tire Pressure Monitoring
+0032 = Adaptive Air Suspension
+0064 = Advanced Frontlighting System (AFS)
+0128 = Adaptive Cruse Control (ACC)
+0256 = 70-Liter Fuel Tank (only Front-Wheel-Drive)
+2048 = Switch Option for Bord Computer Levels (MY 2006+)
xxxx?xx: Country
0 = Germany
1 = Rest of World (Left-Hand-Drive)
2 = USA
3 = Canada
4 = Great Britain
5 = Japan (Left-Hand-Drive)
6 = Arabian States
7 = Australia
8 = Rest of World (Right-Hand-Drive)
9 = Japan (Right-Hand-Drive)
xxxxx?x: Seatbelt Warning (3-6 = MY 2005+ only)
0 = No Seatbelt Warning
1 = Seatbelt Warning (EU-NCAP)
2 = Seatbelt Warning (NAR Old)
3 = Seatbelt Warning (NAR New)
4 = Seatbelt Warning (EU-NCAP incl. Passenger)
5 = Seatbelt warning (NAR Old incl. Passenger)
6 = Seatbelt Warning (NAR New incl. Passenger)
xxxxxx?: Illumination
0 = Needles OFF and Scales OFF (Term. 15 ON / Term. 58 OFF)
1 = Needles ON and Scales OFF (Term. 15 ON / Term. 58 OFF)
2 = Needles OFF and Scales ON (Term. 15 ON / Term. 58 OFF)
3 = Needles ON and Scales ON (Term. 15 ON / Term. 58 OFF)
gtiller is offline   Reply With Quote
Old 08-20-2008, 04:06 AM   #4 (permalink)
Newbie
 
Join Date: May 2008
Posts: 13
Gallery: (0)
tecman is on a distinguished road
Default

Quote:
Originally Posted by gtiller View Post
Hello Tecman!

Sure enough, the A6 has an 80 litre tank (see attached spec sheet)

When my DIS says Zero Miles - I can only ever get 70 litres into my tank.


... I remember seeing a switch somewhere in VAG-COM saying 70 litre tank, and I am wondering if both yourself and I have the wrong setting, so DIS is telling us we need to refuel too early.


I need to check mine (which I won't be able to do until the weekend unfortunately)
Hello Mate,

Good to hear you again.

It looks like I'm not alone with this "problem". I saw 70 liter tank coding when studying ross-tech wiki, when changing MPG to L/100km on my car, but I didn't pay attention, whether it's coded or not. If you are right, it means that the value 256 is added to 4 first digits, and that would explain why fuel gauge shows empty when you consume 60-70 liters of fuel.

I'll connect VAG today and we will see if your theory is right. I hope it's right!!

Because of this issue, I wasn't able to set record of 1000km on one fuel tank as I was scared that I'll run out of fuel on motorway. I did 900km from Dunquerke up to south Berlin ring, but stopped for refueling when reserve light came on and there was 30 km left on the tank. I was surprised at the pump, that I could put 60 liters of fuel when I had first pump stop! At least 15 liters for use which could give me easily 200km more on the tank.
I was cruising from UK to Poland at 150km/h speed for most of the trip and I did 6.6L/100km (42mpg) with 3 people on board and loaded trunk.

Regards,
Tecman

Ps. APS+ project completed with 100% success
__________________
Audi A6 Avant (4F) 2005 UK spec
3.0 TDi Quattro
Retrofitted: Anti-dazzle rear view mirror, DVD Navi, APS+
tecman is offline   Reply With Quote
Old 08-20-2008, 03:02 PM   #5 (permalink)
Newbie
 
Join Date: Apr 2008
Posts: 17
Gallery: (0)
gtiller is on a distinguished road
Default

Yes, I get between 600 & 625 miles to a tank on a long run (depending upon how fast I drive)

90% of my driving is on the motorway.


I can get an absolute maximum of 73 litres of fuel in - that is from full to the brim (I can see the fuel lapping around the flapper valve at the neck of the filler) to when the DIS is telling me zero miles.

However, if i top up the tank when the needle is on 1/2 tank, I can get about 40 litres in.

1000 kilometres is 621 miles, so that would be about right with your finding too!
gtiller is offline   Reply With Quote
Old 08-21-2008, 03:18 AM   #6 (permalink)
Newbie
 
Join Date: May 2008
Posts: 13
Gallery: (0)
tecman is on a distinguished road
Default

Quote:
Originally Posted by gtiller View Post
Yes, I get between 600 & 625 miles to a tank on a long run (depending upon how fast I drive)

90% of my driving is on the motorway.


I can get an absolute maximum of 73 litres of fuel in - that is from full to the brim (I can see the fuel lapping around the flapper valve at the neck of the filler) to when the DIS is telling me zero miles.

However, if i top up the tank when the needle is on 1/2 tank, I can get about 40 litres in.

1000 kilometres is 621 miles, so that would be about right with your finding too!
I've checked my Instrument Cluster coding last night, and unfortunately I didn't have 70 liters tank coded (+256).

Mine Instrument cluster was coded as 2053XXX, which translates to:

+0001 = Quattro (Standard)
+0004 = Vehicle with Clutch (NO Automatic)
+2048 = Switch Option for Bord Computer Levels (MY 2006+)

When I added +256, the fuel tank needle dropped down for a second and restored its position again. Miles on tank dropped from 175 to 165. I've switched original coding back.

If there is a problem, I'd suspect fuel tank overfilling valve...


Regards,
Tecman
__________________
Audi A6 Avant (4F) 2005 UK spec
3.0 TDi Quattro
Retrofitted: Anti-dazzle rear view mirror, DVD Navi, APS+
tecman is offline   Reply With Quote
Old 08-24-2008, 03:08 PM   #7 (permalink)
Newbie
 
Join Date: Apr 2008
Posts: 17
Gallery: (0)
gtiller is on a distinguished road
Default

Had a look on VAG-COM this afternoon.

My instrument module is coded as follows:

Address 17: Instruments Labels: 4F0-910-***-17.lbl
Part No SW: 4F0 910 930 A HW: 4F0 920 980 M
Component: KOMBIINSTR. M73 H15 0630
Revision: 01000000 Serial number: 4PX34ZR55
Coding: 3073413
Shop #: WSC 00411 210 66327

3073 is to include the hidden value +1024 Vehicle Symbol Avant/Wagon

When you have a door or the tailgate open, do you see a saloon or an estate on your DIS?

If you see a saloon, you need to add +1024 ... you will then see the display is switched to a nice picture of an estate!

A6 3.0TDI fuel tank question-1-17-instrument-cluster.jpg


Regarding the fuel tank issue - I found some bits and pieces under the adaptation that need to be looked at... it looks like we can configure/calibrate the settings, which means better accuracy!!!

See Here:

A6 3.0TDI fuel tank question-2-adaptation-ch3.jpg

A6 3.0TDI fuel tank question-3-adaptation-ch29.jpg

A6 3.0TDI fuel tank question-4-adaptation-ch30.jpg

A6 3.0TDI fuel tank question-5-adaptation-ch31.jpg

Two more attachments in the next post (limited to five per post :-( )
gtiller is offline   Reply With Quote
Old 08-24-2008, 03:12 PM   #8 (permalink)
Newbie
 
Join Date: Apr 2008
Posts: 17
Gallery: (0)
gtiller is on a distinguished road
Default

Last two screenshots:

A6 3.0TDI fuel tank question-6-adaptation-ch32.jpg

A6 3.0TDI fuel tank question-7-adaptation-ch33.jpg


I think we need to do some homework on this little lot!

The Ross-Tech wiki is down at the moment, but when it's back up, we need to start there!
gtiller is offline   Reply With Quote
Old 08-25-2008, 02:15 AM   #9 (permalink)
Newbie
 
Join Date: May 2008
Posts: 13
Gallery: (0)
tecman is on a distinguished road
Default

Hi,

I knew about mpg calibration in Instrument Cluster and currently have 115 value. I didn't know about other stuff.

Does it make any sense to you? Which values to change to adjust it? What is the "wet calibration" ?

I'll check the car symbol on my DIS, but my DIS is mono one, so I don't think it make any difference.

Regards,
Tecman
__________________
Audi A6 Avant (4F) 2005 UK spec
3.0 TDi Quattro
Retrofitted: Anti-dazzle rear view mirror, DVD Navi, APS+
tecman is offline   Reply With Quote
Old 08-25-2008, 12:00 PM   #10 (permalink)
Newbie
 
Join Date: May 2008
Posts: 13
Gallery: (0)
tecman is on a distinguished road
Default

Following your findings, I've modified mine instrument cluster like that:

channel 29 (default 141), modified to 144 (+075L)
channel 30 (default 128), modified to 144 (+4 L)
channel 33 (default 128), modified to 144 (+4 L)

in theory it should give me +8.75L more on the gauge. We will see how it will go.

I did some tests on ch29 and 30, by decreasing it to minimum value of 100 (96 is documented as minimal, but it didn't accept the coding), and gauge moved from F to middle of 3/4 and F, so it looks like you have found the proper way of calibrating the gauge reading!

Yesterday I filled up the tank with 70 litres of diesel (63 to the first pump stop). Before filling, it was near reserve bar, but reserve light didn't come on. I'll try to refill again about the same time. It should be more fuel going into the tank than before (circa 9L more).

Ps. I have monochrome DIS, and +1024 coding didn't do anything on my instrument cluster.

Regards,
Tecman
__________________
Audi A6 Avant (4F) 2005 UK spec
3.0 TDi Quattro
Retrofitted: Anti-dazzle rear view mirror, DVD Navi, APS+
tecman is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply

  Audi Forums > Audi Models > Audi A6, RS6, S6 and 100 Forum > C6 Forum


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Powered by vBadvanced CMPS v3.2.2

All times are GMT -5. The time now is 11:42 AM.




Garage Plus vBulletin Plugins by Drive Thru Online, Inc.

Content Relevant URLs by vBSEO 3.3.2