Fuel Gauge - BMW Forum

4griswalds · 07-20-2005, 06:50 PM

While running some errands today, I checked to see how many miles I had left on 1/4 tank. Showed about 98 miles and since I was only going to be driving 5-6 miles, thought "no problem". Within 15 minutes and only 4 miles driven in stop & go traffic I was shocked to see I was down to 73 miles remaining and the mileage was decreasing every 2-3 seconds as I drove.(68 miles now) I thought I must be leaking fuel, but when I checked, that wasn't the case....whew! When I started to drive again the miles started adding up again until I was back up to 93 miles in reserve!!! WHAT? I decided to get some gas to be on the safe side and when I drove away from the station........I started losing miles again, FAST! Anyone have any ideas what that's all about???? Thanks

///M Power · 07-20-2005, 07:25 PM

That's weird. I know on my OLD e34 OBC it shows my miles left on the tank but doesnt fluctuate much. MAYBE in the e46/e90 (whichever you have), it depends on acceleration and gives you the estimated miles at the given rpm/speed you are running at. Is this the first time you paid attention to it?

Bear · 07-20-2005, 09:06 PM

A bad fuel sending unit (in the tank) will do what you are seeing.

nathan56989 · 08-10-2005, 08:24 PM

This is made to change. in stop and go it will go down in mileage when on the highway it will go back up. it takes a calculation of the fuel level and your driving habbits. ( meening that if someone drives with the accelerator pedal on the floor they won't get as much miles out of a tank as someone that light throttles the vehicle) As for the reserve message I'm not sure about that one.