[The X Men]

I just had my first fill up today. Computer reads 40 miles to empty and MPG average is around 18. It took 16 gallons to fill the tank and the tank capacity is 18.3 gallons. That mean I had 2.4 gallons left, at 18 MPG, I could have gone another 41.4 miles. Seems like the miles to empty computer was right on the money. Does that mean when the miles to empty hits zero, there is no spare fuel in the gas tank left? What have you guys been experiencing as far as reserve gas in the tank.

[BigKutta]

The miles to empty is a dynamic calculation based on recent driving patterns and condition. you could drive 3/4 of the tank in the city and the indicator would may show you have 50 miles left, and then you hit the freeway and based on this new driving condition, the indicator may adjust to 100 miles. Its dynamic and it changes. In your case it just happened to work out I think.

On to your other point, I have never driven my F10 to zero. I once did that on my MB ML on a highway (scary doing it in a gas guzzling SUV), the indicator showed 0 and I had no choice but to keep driving 2-3 more miles to get to the gas station. i made it so I assume there is reserve gas there, likely the same for the BMW.

I remember when I bought my e46. The Sales rep told me to never run the tank down to the last few drops because that can cause issues with the fuel filter in BMWs. For 10 years now, I have only filled up the tank when the low fuel indicator light comes on, and never before. But i never let it run down to 0 miles. I have never had an issue

[The X Men]

I try to fill up my tank when the miles to empty reads about 50. I understand your point about the mile to empty difference due to recent driving condition.
I posted this because I am a bit surprise to calculate out zero gas reserve when the mile to empty read zero. Usually, on my other cars, the same calculation will yield about 0.5 to 1 gallon left in the tank when the miles to empty computer reads zero. I guess when my 535xi's mile to empty reads close to zero, I better take it seriously.

[10beers]

In my old E90 I took it don to within 10 miles on empty before but like your calculations it filled up as expected so not sure exactly what to expect upon zero?

[psyxologos]

Originally Posted by BigKutta

I remember when I bought my e46. The Sales rep told me to never run the tank down to the last few drops because that can cause issues with the fuel filter in BMWs. For 10 years now, I have only filled up the tank when the low fuel indicator light comes on, and never before. But i never let it run down to 0 miles. I have never had an issue

My E46 (330 ci SE), like many others in the UK always developed an electrics/electronics malfunction if I let it go close to say 10 miles to empty. It was well documented from other users in a E46 forum. Some weird combination of lights would come on, the Sat Nav would start rebooting etc. Freaky stuff...

[konasunset]

I have heard that with any car it is never a good thing to run the fuel tank close to empty because this can potentially harm the fuel filter. Apparently, a lot of "junk" can eventually accumulate at the bottom of fuel tanks.

[BigKutta]

Originally Posted by psyxologos

My E46 (330 ci SE), like many others in the UK always developed an electrics/electronics malfunction if I let it go close to say 10 miles to empty. It was well documented from other users in a E46 forum. Some weird combination of lights would come on, the Sat Nav would start rebooting etc. Freaky stuff...

yeah, I remember this was a concern in the e46 community. I always filled up once the light came on and never had a problem.

One freaky thing did happen to my e46. I drove the airport one cold winter day with the fuel light on as soon as i left home. I was running late so no time for gas, so drove 30 miles to the airport. I left my car in the cold outdoor parking lot for 3-4 days, and when I returned went straight to airport gas station to fill up. The damn gas cap would not twist off. Almost like there was a vacuum built up inside and the thing was sealed shut. I had everyone in the gas station give it a shot to no avail, and to my embarrassment. Finally some dude took out his wrench and twisted it off literally breaking the cap off. Luckily the cap was a cheap replacement. This repeated itself again under cold conditions when I ran the gas too low, but luckily I was able to twist it off, but since then I never let the range go too low (like below 20 miles in the winter). I think the lack of gas and the cold weather really changes the volume and air pressure to cause this condition. Just a FYI for all.

[ace_pilot]

Originally Posted by BigKutta

yeah, I remember this was a concern in the e46 community. I always filled up once the light came on and never had a problem.

One freaky thing did happen to my e46. I drove the airport one cold winter day with the fuel light on as soon as i left home. I was running late so no time for gas, so drove 30 miles to the airport. I left my car in the cold outdoor parking lot for 3-4 days, and when I returned went straight to airport gas station to fill up. The damn gas cap would not twist off. Almost like there was a vacuum built up inside and the thing was sealed shut. I had everyone in the gas station give it a shot to no avail, and to my embarrassment. Finally some dude took out his wrench and twisted it off literally breaking the cap off. Luckily the cap was a cheap replacement. This repeated itself again under cold conditions when I ran the gas too low, but luckily I was able to twist it off, but since then I never let the range go too low (like below 20 miles in the winter). I think the lack of gas and the cold weather really changes the volume and air pressure to cause this condition. Just a FYI for all.

The gas tank vent must have closed off. It's nothing to do with temperature.

Ace

[Jim776]

Originally Posted by The X Men

I just had my first fill up today. Computer reads 40 miles to empty and MPG average is around 18. It took 16 gallons to fill the tank and the tank capacity is 18.3 gallons. That mean I had 2.4 gallons left, at 18 MPG, I could have gone another 41.4 miles. Seems like the miles to empty computer was right on the money. Does that mean when the miles to empty hits zero, there is no spare fuel in the gas tank left? What have you guys been experiencing as far as reserve gas in the tank.

Hmmm...I have never driven to zero but I do take it seriously. In my quest for a BP gAs station I often get down to the last 10 -20 miles

[10beers]

Ok just got back from a lo weekend of driving and can say the mileage to empty is nearly dead on accurate. Drove it down to the last drops in the tank. When refueling it took 66l to refill and capacity is 70l. I had reset consumption during highway section and was getting nearly 30 mpg at the time. I would say it would get to zero prior to actually running out of fuel by about 5 miles under light throttle conditions.

[bongo77]

I always figure the BMW engineers are as conservative as most of their drivers so I have run the car down to zero a couple of times when I've had to.

The remaining miles just shows "--:--" , so I reset the trip meter to zero while I desperately look for a petrol station. I've had almost 20 miles past zero before.

Note that I do not recommend this practice at all- and I fully agree with the other comments about not dragging up detritus from the tank into your filter.

It's just that you shouldn't worry unduly when you're down to your last 10 miles- you're not quite running on vapour!

[arnsbrae]

Originally Posted by bongo77

I always figure the BMW engineers are as conservative as most of their drivers so I have run the car down to zero a couple of times when I've had to.

The remaining miles just shows "--:--" , so I reset the trip meter to zero while I desperately look for a petrol station. I've had almost 20 miles past zero before.

Note that I do not recommend this practice at all- and I fully agree with the other comments about not dragging up detritus from the tank into your filter.

It's just that you shouldn't worry unduly when you're down to your last 10 miles- you're not quite running on vapour!

Me too in an E60 520d. Twice. Hope I never do it again...