a6 3.0 tdi quattro

[leslie.capewell]

Hello everyone, need help with fuel tank sender,

fuel gauge has just gone crazy,

sometimes reads full, then drops to mt. and warning light comes on even when half full.

been quoted £600 by stoke audi to fix this , anyone any info that may help me,

is it a diy job or audi main dealer only thing,

many thanks ...les........

[666]

Hi , I cant help you, but mine is also faulty, it shows half a tank when it is empty? the garage has had it on the computer and they can move the gauge to all levels and it shows its ok, they seem to be able to tell how many gallons are in the tank which also shows correct with the gauge?  they want to drive it to see what happened over a longer period and over night? they seem to say its all ok, but it isn't as I ran dry and it was still showing half full.  now what. 

[Tech]

the problem is caused by resistance in the connectors between the two tank senders, inside the fuel tank.  The connectors require cutting out and replacing, along with part of the wiring.  Its a bit of a messy job, and a potentially dangerous one if the correct procedures aren't followed

[666]

Thanks for the reply, don't suppose you have a diagram of what needs to be done or know where I can get one, its back at the garage on Tuesday and they wont have a clue,

[666]

I took the A6 back to the garage and they took it to an Audi expert who simply re programed the two senders to speak to each other and all works fine now, no need for any cutting or changing sender units. thanks all.

I am checking the MPG to make sure its correct but I seem to be getting 42 home to work and 47 on a good run. not bad at all.

[Tech]

Soz, completely forgot to reply to this.  I did not actually have any pictures anyhow. Seems a little implausible what they told you about 'programming the senders to talk to each other'.  The senders have no programmable control units built into them, they are simply potentiometers that send a resistance value straight to the instrument cluster, which makes a calculation on fuel level from the two resistance values.  

 

However, if its fixed, its fixed, so happy days!

[Andya6]

I find your quote on mpg somewhat surprising mine on the motorway will do around the 40 mark urban / town it's looking around 25

[666]

Hi Andya6, I have had some work done on the A6 since I put this posting, its had a new Battery management unit and ECU , to stop the continuous warning lights , its now running great, and I can confirm I am still getting 42-44 on local countryside runs and around 48 on a motorway run on average. I have done the actual reading with full tank and calculate mileage and then refill etc, its ok. It is a 3.0 diesel Quattro s-line. I don't do much sitting in traffic in city centres.

[Andya6]

I've just worked mine out this is made of a list of the fuel amount the cost per litre and the total miles covered over the last 3 months and it works out its averaging ............25.6mpg the car has 81500 miles on the clock it's a Le man auto Quattro I think it should be better than that by far my old 1996 a6 2.6 set are which is used everyday is the same if not better than that !!!!

[666]

Andya6, I have looked up the book MPG and most have it around 40mpg on average, so your 25 is a bit bad. Mine is a 05 V6 tip auto, and has 95k on it now, but for the size of the car and weight over 40 has got to be good but 25 not so, maybe needs a visit to the dealer.