My fuel gauge acts funny. It goes to zero when the car is off, it goes to max when the tank is full, and then descends plausibly as I burn gas...but stops at 3/8 and goes no lower (except when the car is off). The low fuel light is still working, and is pretty accurate - last time it lit up, a fillup took 19 gallons. The OBC accurately reports the range, too, so I'm pretty sure that whatever is actually measuring the fuel level is functional. Any ideas what it could be? None of my other gauges act funny (except for the occasional leap in my speedo when slowing down to a crawl), so I'm pretty sure it's not the instrument panel capacitors, either.

a lot of the older BMWs had this problem. mine does something similar. well it used to. it would work perfectly when filled, as soon as i got down to quarter of a tank it would fluctuate. one minute show empty, the next show quarter, then half, then empty and so on. my light never worked though.

i've recently had a new fuel system put in. new pump, AFM and o2 censor, i also had the lines cleaned out. and ever since then, it is constantly showing empty. not even the OBC detects any fuel (shows --- range to empty. consumption works fine though). so i'll be taking it back to the workshop to get them to fix it up.

i wouldn't have a clue as to what is causing it sorry, but i'll be paying attention to this thread. there was a guy with an E30 over on eurocca.net who had a similar problem. he said he took out his instrument cluster and cleaned the connections for the fuel gauge and it worked fine. maybe try that?

I'm positive it's something with the gauge itself. Range is accurate, and doing a "lightshow" revealed that the gauge would stumble up to 1/4, hesitate, stumble up to 3/8, stop, and fall back down. It's supposed to rise smoothly, then without hesistation, fall smoothly. At least, that's what the temp and mpg gauges do.

a lot of the older BMWs had this problem. mine does something similar. well it used to. it would work perfectly when filled, as soon as i got down to quarter of a tank it would fluctuate. one minute show empty, the next show quarter, then half, then empty and so on. my light never worked though.

i've recently had a new fuel system put in. new pump, AFM and o2 censor, i also had the lines cleaned out. and ever since then, it is constantly showing empty. not even the OBC detects any fuel (shows --- range to empty. consumption works fine though). so i'll be taking it back to the workshop to get them to fix it up.

i wouldn't have a clue as to what is causing it sorry, but i'll be paying attention to this thread. there was a guy with an E30 over on eurocca.net who had a similar problem. he said he took out his instrument cluster and cleaned the connections for the fuel gauge and it worked fine. maybe try that?

Replacement fuel injectors fixed the same problem for me. Though my light would come on. And I had an O2 sensor put in about 2 months prior, but didn't see any effect on this. Isn't there also a fuel level sensor in the tank that can get dirty or corroded?

throw in a bottle of techron that may fix your problem