How much fuel left when Reserve light comes on?

[Clan]

Originally Posted by dcr69

I did my first proper tank refill yesterday on my D4 FWD Manual.

I am used to computers that fib as to how much fuel is left (my Toyota would say I had a range of 20 miles when I could put on 55 litres in a 60 litre tank).

Anyways, being dumb, and making a 70 mile motorway journey, I ignored the Reserve light (which came on at around 50 miles left) and went off the trip computer telling me the range left.

When it got to 20 miles left I decided to leave the motorway and get to a fuel station.

On the slip road (uphill) the range went from 20 miles left to "---" and stayed like that for 2 miles to the petrol station.

I was expecting to get about 65 litres into the fuel tank.

I actually managed to put in 73.08 litres - definitely NOT something that I am proud of
Bear in mind the tank is officially 70 litres, plus the plumbing from the filler cap.

Incidently, I managed 777 miles on the tank and averaged 48.33mpg with a mix of
- about 500 miles on the motorway, locked in cruise control at 56mph - an indicated 58 mph on the computer - hey, they always overestimate, but GPS never lies
- about 200 miles on decent windy A-roads, speeding.
- the rest around town

So, from here on I will search for a fuel station when the reserve light comes on.

Has anyone ever run out of fuel, or run the fuel levels so low they got more than 73 litres in?

Your Fuel Gauge is the only device which tells you how much FUEL is left in the tank , It is a precision moving coil Instrument and very accurate especially near the empty end ...

[fleming164]

I spent quite a few years driving a car with a seemingly non-linear fuel gauge so have always compared how much fuel I can get in when I *think* it is almost empty to the quoted size of the tank.

Having said this, my 2.0D S40 can be a tad unpredictable. I first ran it to --- and drove approx. 10 stop start miles before a fill up and only managed to squeeze 46 litres in a 52 litre tank!

Last month we were travelling in France and armed with this knowledge and wanting to find a specific brand of fuel we skipped a couple of service stations and pulled into a garage after driving with --- for about a mile or so and I managed to fit 50 litres in!

I generally fill up with ~60 miles remaining as it seems to plummet disproportionately quickly after that!

[Fursty Ferret]

I've had about 20 miles past the -- and flashing red light on my V60, including an engine stop and start. Unpleasant whining noise from the lifter pump and main fuel pump though.

[Grimble]

Have regularly filled up over 75 litres (to the brim).
I find that I can get up to 6.5 litres more in to the tank from the fist click of the fuel lever.

As most of my journeys are similar, I rely on the trip counter quite a bit as well as the gauge. Can always get over 700 miles on a brimmed tank.

[Electronix12]

Originally Posted by Clan

Your Fuel Gauge is the only device which tells you how much FUEL is left in the tank , It is a precision moving coil Instrument and very accurate especially near the empty end ...

Not sure I agree with you here. Gauge on mine below 10%ish is making assumptions IMO.

I’ve had it go to —- after 650 miles and almost 800 miles with the MPG on all the trips in the same range (I.e 45-47). Result being I fill up anywhere between 65 and 76 litres.

I’ve had it go from 60 miles remaining to nothing overnight on the level...

In cases where I’ve been doing motorway miles up until empty I get heading on for 800.
If I do motorway miles then start doing stop start stuff after reaching 10% it quickly drops to empty, yet I then only fill up ~70 litres...

Not ran out yet!

[Clan]

Originally Posted by Electronix12

Not sure I agree with you here. Gauge on mine below 10%ish is making assumptions IMO.

I’ve had it go to —- after 650 miles and almost 800 miles with the MPG on all the trips in the same range (I.e 45-47). Result being I fill up anywhere between 65 and 76 litres.

I’ve had it go from 60 miles remaining to nothing overnight on the level...

In cases where I’ve been doing motorway miles up until empty I get heading on for 800.
If I do motorway miles then start doing stop start stuff after reaching 10% it quickly drops to empty, yet I then only fill up ~70 litres...

Not ran out yet!

I'm going by the many different volvos I've driven under low fuel conditions , many times the level has been showing as empty on the gauge and sometimes slightly below ! I've never run out either … Even my 340 is very conservative , I think if you do run out in a volvo , either there is something wrong with the float or you have been foolish ... Remember the fuel gauge is the only thing to look at .

[Baxlin]

What’s a reserve light?😇

I never let mine get below a quarter full, having once been let down by an inaccurate fuel gauge.

My JZR doesn’t have a fuel gauge, nor a reserve facility, so I reset the trip each time I fill up, and judge by the miles covered.

[AndyJudge]

I try not to let mine get to the point where the light comes on.
When it does I disregard the Miles to empty & try to refuel within the next 10 or so miles.

Is it really worth risking actually running out ? I did once many years ago during a baking hot summer on the Isle of Wight. The 6 mile round trip hike to get fuel & back to the car wasn't pleasant in the slightest.


By many years ago I'm saying 30 so before the age of widespread mobiles & in the days of more optimistic fuel gauges.

[nu11eaf]

Originally Posted by dcr69

I did my first proper tank refill yesterday on my D4 FWD Manual.

I am used to computers that fib as to how much fuel is left (my Toyota would say I had a range of 20 miles when I could put on 55 litres in a 60 litre tank).

Anyways, being dumb, and making a 70 mile motorway journey, I ignored the Reserve light (which came on at around 50 miles left) and went off the trip computer telling me the range left.

When it got to 20 miles left I decided to leave the motorway and get to a fuel station.

On the slip road (uphill) the range went from 20 miles left to "---" and stayed like that for 2 miles to the petrol station.

I was expecting to get about 65 litres into the fuel tank.

I actually managed to put in 73.08 litres - definitely NOT something that I am proud of
Bear in mind the tank is officially 70 litres, plus the plumbing from the filler cap.

Incidently, I managed 777 miles on the tank and averaged 48.33mpg with a mix of
- about 500 miles on the motorway, locked in cruise control at 56mph - an indicated 58 mph on the computer - hey, they always overestimate, but GPS never lies
- about 200 miles on decent windy A-roads, speeding.
- the rest around town

So, from here on I will search for a fuel station when the reserve light comes on.

Has anyone ever run out of fuel, or run the fuel levels so low they got more than 73 litres in?

I would always trust the low fuel warning light, as it is going off actual fuel level, (usually about 2 gallon) the remaining miles to go will vary depending on how you drive, putting your foot down and it will estimate how may miles you will get driving like that, ease off and drive gently it recalculates and will show a higher miles to empty.
I have ended up with a larger miles to empty than when I set off, as before a trip I was driving in town getting about 25 - 28 mpg but on the longer trip at a steady 60 mph the miles to empty increases as the MPG goes up to around 44mpg.
Adversely after a long steady run the miles to empty can show maybe100 mile to empty as you pull off the motorway but drop dramatically once you join urban roads as your mpg reduces but if you had stayed on the motorway you would get 100 miles on remaining fuel.
It does not tell lies just calculates for conditions at the the time.

GPS mileage does not always give an accurate measurement of miles travelled as some measure from point A to point B in a straight line (miles over ground) so if you are on a road with lots of bends you will travel a greater distance, the indicated speed on some GPS works the same, timing how long it takes to cover miles over ground but it will under estimate the speed on a winding road as you travel further.
The car adometer and speedo will be more accurate.

[cardiomike]

the range left is purely a function of the on board computer mpg and tank estimate. the way a car is driven can determine the range left- ive had a full to the click tank and managed a remaining range from 770 to 1106 miles just by going down hill for a bit.
So.. fuel expands with heat-so depending on when you fill up-you can get more in the tank if its early on a cold morning with cold ground-if its a hot day like lately you might get less. id actually fill up if your a quarter empty if the issue is critical to your journeys.