quattro100

I am still having problems filling my car with gas. It is the strangest thing and never happened for the first 10 months I owned the car. It will only allow me to add 3/4 of a gallon at a time and the lever clicks off. I tried many times at different places. What is strange is I dont have the usual release of gas pressure when I remove the gas cap and I hear it backing up when filling. Is there a tube in the pipe that goes to the fuel tank that may be blocked? Any ideas? Help!!!

PaulW

Sometimes (like once in a very long while), I have the same problem, always thought it was just the pump....but I don't have it now, it's been months since it happened.

Maybe a vent is clogged or a check valve not opening?

KMU

the gas cap loose, it turns on the check engine light on after the car runs. That means the computer has a sensor input to let it know if a leak exists. The first generation OBD2 systems had a solenoid on the charcoal canister that closed on start-up, and the computer recognized when a short vacuum was applied and didn't drop(as I remember). I would think think there is a solenoid that's open(allowing some venting) when the key is off, and closed when running. I would check the operation of that solenoid and the line(s) to it. I don't know if Audi's operate the same, but many manufacturers do.

Always Overcharged

these go into the evap system and if one is blocked or the evap cannister is crook it may be the cause.
Do you have vagcom-if so try scanning the evap and check measuring blocks.
Thyere is also a little tube in the tank that connects to the fuel pump assembly but this doesnt usually affect filling -only gas supply to the pump under 3/4 full

rhann

I just got a 2000 A8L used and am having the same problem. Did you ever find a resolution? Should my Audi dealer be able to fix this?