How much fuel left when Reserve light comes on?

[Grimble]

Originally Posted by Spitfire4

Mrs S used to work in a garage, a ford one, and the pumps were checked regularly for accuracy, but when you keep clicking on and off, trying to get a bit more in, some of it is air, so as she used to tell me "you're pumping air not fuel". Touch wood, haven't run out of fuel but try to keep a certain amount in, another nag from Mrs S, telling me it's not good for a diesel as it has to be reprimed whatever that means!

Not sure I believe that first one. The pump in the cabinet is designed to be completely isolated from any possibility of air ingress. The last thing you want in an enclosed space is a combination of electricity, fuel and air. Unless in a combustion chamber of course.

[GMcL]

Page 255 of my manual describes how to prime the system under the heading Empty Tank. It does also explain that the car may need to go back to Volvo for venting.

[wimorrison]

Originally Posted by Grimble

Not sure I believe that first one. The pump in the cabinet is designed to be completely isolated from any possibility of air ingress. The last thing you want in an enclosed space is a combination of electricity, fuel and air. Unless in a combustion chamber of course.

There are many electric pumps that run submersed in may substances that are a lot more volatile than diesel or petrol, even ones that can be used in hazardous areas that have gas or explosives - they simply use brushless motors just like good electric screwdrivers and other high end tools do do now, no sparks to worry about

[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?

But it does lie , in all circumstances except a straight and level road .

The gauge is a precision instrument and is accurate especially at the low end , so when the needle runs off the edge of the scale scale expect to run out any time if it hasn't already that is .

[Grimble]

Originally Posted by wimorrison

There are many electric pumps that run submersed in may substances that are a lot more volatile than diesel or petrol, even ones that can be used in hazardous areas that have gas or explosives - they simply use brushless motors just like good electric screwdrivers and other high end tools do do now, no sparks to worry about

Of course there are, I work in the offshore oil business where we have seriously sized pumps running in hazardous areas, but I believe that the pumps used on forecourt pumps are in the above ground cabinet, rather than submersed in the fuel tank. The point is to keep oxygen away so that there is minimal chance of a combustible mixture coming in to contact with an ignition source. All pump nozzles and car filler tubes are non-ferric for the same reason. Also relevant is the ban on using your mobile when filling up, which given Samsungs recent difficulties, now seems a bit more reasonable. Even a brushless motor has electrical connections.

[wimorrison]

A pump that is submersed in fuel is significantly less likely than a pump running in air to cause a fire of an exposion you require 3 items to be available at the same time.

Fuel, oxygen and heat - if submersed completly then there is no oxygen, therfore no chance of combustion.

The electrical connections do not generate any heat, unlike the spark in a brushed motor - it is this spark that craetes the heat for the combusion to happen in air.

The ban on mobile phones was created to address the analogue 'phones of yesteryear and has simply remained in the digital era - same as the use of 'phones in aircraft

[Grimble]

The ban on phones in aircraft was/is allegedly to do with radio wave interference, not an electrical power issue. Otherwise laptops and music players would also be banned.

I did mention that you needed fuel, air and a source of combustion in my earlier post.

Electrical cables connected to a load can and do overheat, check the one on your domestic iron after half an hour or so of use.

My original point was that you would not be pumping any air into your fuel tank by 'clicking' the pump, as there would be no air in the system in the first place by design, for safety reasons.

[NigelDay]

In post #16 I reported a fill of 75.96 litres, but I now believe this must have included a 10 litre can.
This week, I knew I was running low so had the precautionary can in the boot.
At 730 miles, the '20 miles to empty' disappeared and the red light came on.
I reached the filling station at 736.4 miles (phew !) and filled to the brim with 74.35 litres. So, I reckon the true capacity of the tank is 75 litres, which would tally with 20 miles remaining at 730 miles driven at an average consumption of 45mpg.
As already explained, I don't make a habit of this but filling stations are thin on the ground up here and unplanned trips in the wrong direction don't help.

[ADBS65]

Whilst traveling in France with the family I decided to play Top Gear fuel light bingo to liven up the journey. I was on the motorway and had the benefit of the range left information that the kids were unaware of, a safety net if you like. Anyway I get down to 20 miles left and decide to skip the approaching fuel station as I assumed there would be another within 20 miles. A short distance down th road I am forced to brake for the toll booth, at which point my range goes ----- not perturbed, I think it will come back on when I acceleration away from the booth, err but it doesn't. I exit the motorway as my lad is using maps to find the nearest filling station. On arrival I find its shut down :-( I have been driving some distance now, close on 20 miles! The locals send me toward the next nearest one, TBH I am thinking the worst, however, I literally just make it. I filled up and put 78 litres in, I must have been on vapour! Lesson learned, and I have not played the game since!

[Bigjap]

Originally Posted by RoyMacDonald

If you run out completely Nigel don't expect to be able to just put more fuel in and have it start up again. Happened to my friend and the car has never been right since, cutting out at random intervals. The garage wants to renew the whole fuel system.

Roy

Sounds like a garage that are clutching at straws, He will find if the vehicle has ran dry and sucked all the dregs of the tank onto the strum on the intank pump it will be restricted and will be getting starved of fuel. The filter systems are that fine it doesn't take a great deal to cause a restriction.