# How far have you pushed your fuel tank?



## Uber Commuter (May 26, 2017)

I drove home late last night and totally forgot I was low on fuel... Light came on 2/3rds of the way home with 30 miles to empty; unfortunately the closest diesel station I'll use is ~25 miles from my house...

Hit the road this morning keeping a close eye on it; could have stopped at a station 10 miles from home but their diesel is always 10-15 cents higher than anywhere else so I don't really trust the turnover. As the car was pretty well warmed up by then and I was still looking at ~15 miles to empty, I decided to go for it.

I hit "---" empty about 5 miles from the station, but made it in and put almost 15.9 gallons in the tank... :rofl:

So how far has anyone else pushed their diesel? :angel:


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## Doug Huffman (Apr 25, 2015)

*Never even seen reserve. Not worth the risk.*

*Reserve*
After the reserve range is reached:
>> A message is briefly displayed on the Control Display.
>> The remaining range is shown on the computer.
>> When a dynamic driving style is used, such as when corners are taken rapidly, engine functions are not ensured.

The message appears continuously below a range of approx. 30 miles/50 km.

*Refuel promptly*
At the latest, refuel when the range drops below 30 miles/50 km; otherwise, engine functions are not ensured and damage may occur.

BMW X5 Fuel tank Including reserve of (X5 xDrive35i, X5 xDrive35d) approx. 2.1/8, US gal/liters Approx. 22.4/85. IOW reserve at 20 gallons.


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## Uber Commuter (May 26, 2017)

I used to do it regularly with my Golf, and went as much as 50 miles beyond "0 miles to empty" on that car, but I don't really plan to do that with the F30. As I said, was just tired last night and forgot until the "30 miles to empty" warning popped up.

I was just curious if anyone else ever pushed it.


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## jfxogara (Oct 26, 2012)

After driving on "empty" for ten miles I once got 16.635 gallons in the tank. You can see it in my Fuelly entry for January 20, 2017. Many tanks over 16 gallons. Don't recommend though due to fuel's role in cooling the lift pump.


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## jck66 (Nov 28, 2017)

Have taken my 535d down to zero a couple of times and put 17.3-17.9 gallons in (nominal 18.5 gallon tank capacity) so I reckon there's a half gallon left at zero DTE. Coming from VW diesels, I understand the role that the fuel plays in cooling the in-tank pump so I don't like to take it that low, but sometimes circumstances dictate differently.


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## Autoputzer (Mar 16, 2014)

I reset my trip odometer and the on-board computer's (OBC's) MPG when I fill the tank. That way I can easily calculate how much fuel I've burned since I refueled (miles/MPG). I also keep track of the gas pump MPG vs. the OBC MPG. On average, my gas pump MPG is 1.5% better than the OBC MPG. So, I adjust my OBC MPG (multiply it by 1.015) before I do my fuel burned calculation at the gas pump. 

To impress Frau Putzer when she's in the car, I predict how much fuel I will need before I start filling the tank. I'm usually within a couple of tenths of a gallon. Her response is usually "Meow, meow, meow, meow...," which is Catese for "I'm ignoring you."

The miles-to-empty is based on the reading of the fuel gauge and your recent MPG. I'm not sure of the exact definition of "recent." The fuel gauges reading has a lot of errors, and it gets worse over time. The OBC MPG is more accurate. So, the trip odometer-OBC MPG calculation of fuel burned is more accurate.

Both of my cars have an OBC MPG reading. I live where the roads are straight and the land is flat. So, I'm not worried about starving the fuel pump(s) in a turn or on a hill. I run my tank down to one to 1.5 gallons left.


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## lawlknight (Sep 13, 2016)

Uber Commuter said:


> I used to do it regularly with my Golf, and went as much as 50 miles beyond "0 miles to empty" on that car, but I don't really plan to do that with the F30. As I said, was just tired last night and forgot until the "30 miles to empty" warning popped up.
> 
> I was just curious if anyone else ever pushed it.


On a VW you generally have about a gallon of gas left once it hits 0. I have a 2013 VW Passat TDI and can do around 40 miles after 0. Or if I fill up when it hits 0 it takes 17.5 gallons on an 18.5 gallon tank. The BMW will be about at empty when it says 0. I've driven until 0 and put 22.6 gallons into a 22.5 gallon tank. :yikes:


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## glangford (Dec 11, 2013)

The lowest I've ever gone was down to 1/8th a tank. Usually stop and fill with a quarter left.


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## FredoinSF (Nov 29, 2009)

Autoputzer said:


> To impress Frau Putzer when she's in the car, I predict how much fuel I will need before I start filling the tank. I'm usually within a couple of tenths of a gallon. Her response is usually "Meow, meow, meow, meow...," which is Catese for "I'm ignoring you."
> 
> /QUOTE]
> 
> ...


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## Autoputzer (Mar 16, 2014)

I could see how a FUEL RESERVE warning in Donner Pass would cause some discontent, especially in the winter. You're probably all right until she pulls a fork out of her purse.

Alabama, South Carolina, Tennessee, and Virginia are cheap gas states. Although South Carolina has raised their fuel taxes to pay for all of their potholes. Florida, Georgia, and North Carolina are relatively expensive. From our house to I-85's last exit in South Carolina going north is 497 miles. I can do it if I leave home full and there's no traffic jams in Atlanta.

I wish they'd add "Fuel burned since reset" to the on-board information. Then I wouldn't have to ask Frau Puzter "Divide (X) by (Y)."

One of my goals before we move to the foothills is to get my average tank mileage to 400. I'm currently at 396.95.

My longest tank so far in my 535i was 520 miles, 17.2 gallons (in an 18.5 gallon tank) at 30.2 MPG. I had the nav' system counting down my miles to destination. It was after midnight and the temperature was in the low 20's (F). I'd do the math when I'd stop for food or to piss.

Frau Putzer's annoyed by my MPG and fuel range games. But less so than when I had my M3. My game in that car was to do U-turns mostly with the gas pedal instead of the steering wheel. I'd turn off the DSC and start humming the opening lick from "Song 2" made famous in the Madonna-M5 video, and say "Let me see what I can do... sir."

"Damnit! I hope a cop sees you doing this. I'm going to tell him you do this **** all the time and that you also got weed in the car. Your *** will be spending the night in jail."

https://youtu.be/OK3e4Pe8K1k?t=256


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## Michael47 (May 9, 2014)

In the olden days, when running a diesel out of fuel meant you had to replace your injection pump and all your fuel injectors (think about that for just a moment. I'll wait.), risking running out of fuel was a no-brainer.

Today, however, one might actually get away with doing that. Maybe even twice before serious damage occurs. But given the difficulty of having to refill a quart-sized fuel filter, plus blow most of the air out of the upstream fuel lines, the HPFP, and injectors before you can get it running again, it is still a stupid idea. So the closest I've gotten in the last 16 years of driving diesel has been the twice the low-fuel alert chimed, prompting a visit to the very first diesel pump available, even if only to add 5 bucks worth to insure I get to the NEXT station.


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## graphicjunkie (Nov 15, 2016)

I've read countless articles over time, as well as have had multiple mechanics same the same thing...it's very hard on the fuel system to run it really low. 

Simple rule. I never let it get below 1/4 tank. Period. Usually I fill it at 1/2, simply because Im pulling in to get a Monster or something anyway. Just top off.


Don't be lazy.....take care of your ride, and it will take care of you.


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## Autoputzer (Mar 16, 2014)

graphicjunkie said:


> I've read countless articles over time, as well as have had multiple mechanics same the same thing...it's very hard on the fuel system to run it really low.
> 
> Simple rule. I never let it get below 1/4 tank. Period. Usually I fill it at 1/2, simply because Im pulling in to get a Monster or something anyway. Just top off.
> 
> Don't be lazy.....take care of your ride, and it will take care of you.


There's a theory that electric fuel pumps inside the tank are cooled by being immersed in gasoline in a mostly full tank. They're also cooled by the gasoline that is being pumped. Some fuel tanks may be near the bottom of the tank. But, in my two Nissan's they were at the top of the tank.

There's also a theory that running the tank low will cause the fuel pump to pick up sediment and sent it on to the fuel injectors. That's just wrong. The fuel pick-up is at the bottom of the tank, so it picks up any sediment that if the tanks is full or near empty.

For local driving I run my tank down until the low-fuel light comes on. I've been doing this for as long as I've had low-fuel lights or an accurate fuel gauge (1976 VW Rabbit), over 40 years. The lower the fuel when I refuel, the fewer trips I have to make to gas station-convenience stores. These stores are one of the places I have to cross paths with the dregs of society. So, the fewer times I go there the better. I also try to hit these places in daylight and in the mornings if possible, when the dregs are more likely to still be sleeping off the previous night's meth, crack, or booze.

I bought gas after dark tonight (435 miles, 17.1 gallons in an 18.5 gallon tank on my 535i). I had a 9mm Glock in my coat pocket while doing it, though. I could have gone another 12 miles home, and bought gas tomorrow morning. But the station I went to in town has a very generous Pump #8. My gas pump MPG was 3.7% higher than the OBC MPG. 1.5% of that I'd attribute to OBC error. The other 2.2% was free gas, and the gas I had to pay for was $0.10/gallon cheaper than near my house.

Tonight I saved about $1.70 on cheap gas in town (but still Top Tier), about $1.00 on free gas from Pump #8, and almost $4 by blending 1/3 87 AKI and 2/3's 93 AKI to make 91 AKI that my BMW requires. I'll also get about $2.30 in credit car rebates (5% on gas purchases). :thumbup:

I've had two electric fuel pumps replaced under recalls: 1992 Nissan Sentra SE-R (B13), and a 2007 Chevy Cobalt SS. I had a mechanical fuel pump fail on a 1969 Jeep Wagoneer at about 50k miles. My other cars, no problem:

1976 VW Rabbit (155k miles, mechanical fuel pump)
1985 Ford LTD (Fox)(103k miles)
1985 Mercury Grand Marquis (Panther) (98k miles)
1996 Nissan 200SX SE-R (B14) (127k miles)
1997 Honda Civic EX (103k miles)
2000 Chevy Silverado 1500 (74k miles)
2002 BMW M3 (115k miles)
2006 Honda Accord EX (142k miles)
2014 BMW 535i (46k miles)

Frau Putzer flamed out (ran out of gas) the Civic once and the Cobalt once, with no lasting effects. Both of those cars have/had low-pressure electric fuel pumps feeding port fuel injectors. Modern BMW's have both a low-pressure and high-pressure fuel pumps. The high-pressure fuel pumps are necessary for direct injection engines (diesel and gasoline).


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## Michael47 (May 9, 2014)

Autoputzer said:


> There's a theory that electric fuel pumps inside the tank are cooled by being immersed in gasoline in a mostly full tank. They're also cooled by the gasoline that is being pumped. {SNIP}
> 
> Modern BMW's have both a low-pressure and high-pressure fuel pumps. The high-pressure fuel pumps are necessary for direct injection engines (diesel and gasoline).


(a) Thank you for your input about gasoline vehicles. Please note that this particular forum is about diesel vehicles, and none of those in your list are diesels, all are gasoline. It is a simple fact that running a gasser out of fuel is an entirely different experience from running a diesel out of fuel, which fact you would not necessarily be expected to know.

(b) Please, by all means, feel free to drive your vehicles however you see fit, and to fill up the go-juice whenever and however it suits you. Your cars, your money, your convenience, your life.

(c) Yes, indeed, diesel BMWs have high pressure fuel pumps and are direct injection engines. This is the heart of the matter, for it is that high pressure fuel pump that suffers most immediately for anyone who runs a diesel out of fuel. Damaging one by such negligence as to run out of fuel is a potentially very expensive proposition.


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## dzlbimmer (Jul 16, 2017)

graphicjunkie said:


> I've read countless articles over time, as well as have had multiple mechanics same the same thing...it's very hard on the fuel system to run it really low.
> 
> Simple rule. I never let it get below 1/4 tank. Period. Usually I fill it at 1/2, simply because Im pulling in to get a Monster or something anyway. Just top off.
> 
> Don't be lazy.....take care of your ride, and it will take care of you.


In order to keep tabs on whose fuel is in my tank, I'll never do a $5 splash except dire emergency (and even then I'd prefer to take the risk of filling the tank). Same goes for filling at half. I almost never fill up before the light comes on unless I am anticipating going into no mans land, have a planned trip that I am preparing for, or I am near a preferred station and getting close to the low fuel light.

Ive coasted into my preferred stations sweating bullets a couple times. Really dislike doing that.


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## jck66 (Nov 28, 2017)

Michael47 said:


> In the olden days, when running a diesel out of fuel meant you had to replace your injection pump and all your fuel injectors (think about that for just a moment. I'll wait.), risking running out of fuel was a no-brainer.


I'm not sure that's strictly true. (My diesel experience prior to my current car is limited to VW products, so use that as a filter for the rest of this post.)

In my younger days, I stupidly ran both 1.6 ID and 1.9 TDI-powered cars out of fuel a couple of times. On these occasions, it just took a fillup and a bit of cranking to get them up and going again. Both cars were running well when I moved them along years later. Neither of these cars had a lift pump in the fuel tank.

Since I moved on to diesel cars with a lift pump I have been much more careful (but also older and less stupid).  I think it helps that there is both an idiot light and a DTE countdown in the later cars...


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## Robert A (May 18, 2003)

I've gone all the way to zero on remaining miles.


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