Fuel guage problems, S2Avant

[newsh]

Been having problems with the fuel gauge and trip computer since I got this car.
I've run out of fuel with the gauge still reading a 1/4 to 1/2 but when filling the tank the gauge does go to the top.
Also sometimes the fuel range on the trip disappears, just blank, the other functions still work. Then last night the chime went off and empty symbol flashed for the first time ever (never did this before even when I'd run out)
So today I opened up the tank, (there wasn't a lot of fuel, pump only half submerged) and got the sensor and float out.
With an ohms meter on the sensor I found that the variable resistance was intermittent so I cleaned it up and bent the spring on the contact to get a bit more pressure. The resistance then seemed to vary smoothly.
Buttoned it all back up and went and put 60 quids worth in.
The gauge now shows almost full but the fuel range is only 75 miles!

Can anyone throw any light on this? Maybe the sensor is more broken than I thought?

[bertman]

I think there is something on S2 central about how to recalibrate with a full tank of go juice.

[newsh]

I think there is something on S2 central about how to recalibrate with a full tank of go juice.

Cheers Rob!
Right I've had a go at that, I pulled the wee plug out and can adjust both gauge and fuel range pots but neither of them have any effect. The gauge shows nearly full and the fuel amount is 175 (17.5 litres).
And sometimes when I switch ignition on the fuel range shows blank.
So I reckon I might have a cluster issue..

[M2ki]

Probably cold solder joints on the cluster. Trip computer is plugged behind the cluster and gets the fuel level signal from the cluster PCB.

[newsh]

Sorted, tried a spare cluster and it all worked so took original cluster apart and cleaned all the contact pins between the various boards. I've now got a sensible fuel reading which is adjustable.

Something Paul missed in the adjustment procedure on S2 Central is that whilst the gauge is adjusted with a 3mm Allen key, the fuel range pot on the back of the cluster is adjusted down the same hole but with a small diameter flat blade or cross point screwdriver or trim tool. You basically need something thin enough to pass through the 3mm hex in the adjuster shaft and still rotate.

[Mikes2]

I'm seeing similar issues on mine. Fuel range is all over the place. Sometimes 700 followed by E. if I drive and park up and then restart, it's often blank. I've got a new sender in the tank

Was it just the long spike connectors you cleaned up ?

Did you resolder any joints ?

[mcandmar]

Something Paul missed in the adjustment procedure on S2 Central is that whilst the gauge is adjusted with a 3mm Allen key, the fuel range pot on the back of the cluster is adjusted down the same hole but with a small diameter flat blade or cross point screwdriver or trim tool. You basically need something thin enough to pass through the 3mm hex in the adjuster shaft and still rotate.

From memory they both adjust with the allen key, i had to unclip to the adjustment pot and adjust it separately on mine to get the computer in the right ballpark.

[LHD_Kid]

No. John's right.

Allen key, then a long thin cross head to go inside for the adjuster on the little circuit board.

I posted about this some years ago... boogered if I can find it though

[Antsa]

I'm having some issues with my fuel gauge as well. When searched for calibration instructions i found this https://www.audifans.net/ftopict-20868.html Still yet to try, but doing the calibration this way you can leave faulty tank float out of the equation.

[newsh]

Good info

Mine is still not right, I did 200 miles yesterday and it was still reading over half a tank.

I'd set the trip and gauge as best I could with the tank brimmed but it was right up the end of the adjustment.


Still at least I'm getting a reading all the time!

[newsh]

Sender part number seems to be 8A0 919 051 C
Think I'll try and buy a new one.

[Mikes2]

I got mine from Tradition. Was around 80 euros

[newsh]

Yep, ordered today

[newsh]

Arrived

[newsh]

And fitted
Great disappointment as it's still the same as before
The gauge reads 1/4 when it runs out of fuel