Since I bought this car about 3 years back, the fuel gauge has sort of bothered me because it hasnt been acting like I would expect it (or compared to my B7), let me try to explain;
When I fill my tank up to full, the needle will show it as full but it will sit there for a very long time before it drops and when it does it will make a pretty big jump (from full to between 3/4 - Full) and theese small jumps or drops will keep occuring all the way down pretty much, but it seems to become less noticable the lower it goes so at 1/4 and below it seems to act as normal and will go down in a linear fashion to empty.
What I did first of all was to open the tank and clean my fuel gauge sender unit, but that did not fix anything.. I also made sure that the arm wasnt catching on anything inside.
Three days ago I actually swapped the sender unit to a new OEM unit thinking it would fix this, but it seemed to have gotten even worse now.. After I calibrated it (drain tank, put in 8 litres and adjust it in VCDS to hit red mark and fuel warning light) I went and filled it up completely.
Needle only went to 3/4 and very slowly (probably over 30-40 minutes of driving) it climbed to full and started making theese same sudden drops in reading. Most obvious time was when I stopped at the shop and needle was around 90% full and when I came back out and started the car again it only got up to 75%.
I have done the output test in VCDS on the cluster and then fuel gauge needle moves perfectly as it should.
Next step is Im going to open tank again when Im low on fuel to messure both in VCDS and with a multimeter to see if I can find anything abnormal in readings in the full range of the sender unit, but cant do it until I get some more free time on my hands.
Im curious to see if slowly dropping the sender arm actually show any change in Ohm's when reading them in VCDS messurements through the ECU and compare to MM, and if so fuel gauge needle also reacts.
So Im asking if anyone else have any ideas that I can try out once I look into this again, in about a weeks time?
Also, how linear can I expect the fuel gauge to be as fuel goes down? I know the tank isnt symetrical so it will not be 100% linear at all times but could it just be that thoose "small drops" I saw from the beginning was actually within a "normal tolerance"?
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