6N2 Fuel Sender Problem - FIXED

[937carrera]

The fuel gauge on my red GTi isn't working correctly (it wasn't when I bought it). I have run the tests in VAGCOM and the gauge behaves as it should. The resistance measured by the car is the same as on the multimeter.

I have removed the fuel pump assembly and when out of the tank everything works fine, measuring between 55 and 290 ohms as I move the float. When I put it back in the tank (which is close to full) the gauge reads less than 1/4 tank and back down to 100 ohms.

Am I doing something wrong when refitting the pump back into the tank which is causing the float to jam, or has the float lost it's air pocket ?

[alexperkins]

There's a known issue with the grounding on these

I'll have to check the workshop manual for the procedure

[937carrera]

Thanks Alex,

I had read something similar, but having looked at the wiring diagram it didn't make sense as the connector simply has 4 connectors: a feed & return for the pump, the same for the sender.

I tested the assembly out of the car ( residual fuel and fuse 40 removed) and it seemed to be working fine, that's why I thought it was the installation or float that was the problem, but maybe not.

Grateful for anything else you can throw at me

[937carrera]

Just a quick update:

The problem is fixed.

I decided to remove the float and connecting wire from the pump to make sure that it still floated. That was a good idea, as when I tested it out by placing the float through the hole where the pump was I discovered that the fuel level was actually much lower than I thought. I'll know not to be fooled by reflections that give the impression of a much higher fuel level than is the reality.

Next I used another battery and jump wires to drain the tank from the fuel filter and followed the calibration procedure by putting 7 litres of fuel back into the tank. Before I did I checked the fuel gauge and it showed empty and the low fuel light was on.

With 7 litres of fuel in the tank I then did the adaption to calibrate the needle against the start of the red section on the gauge. After I did that I then read the fuel level in measuring block 2. It showed 7.0 litres and 91 ohms resistance. I have read that if there is less than 7 litres of fuel in the tank it will say 7 litres anyway, so maybe my educated guess was about right.

Maybe there was never a problem and what the previous owner told me about the gauge not working was just wrong, or maybe my cleaning of the rheostat fixed the problem. I'm hoping to get an MOT test done on Saturday, so all I need to do is tax her and go to a petrol station for the ultimate test.

[alexperkins]

Happy days. Was going to say try that but you beat me to it!