Running out of fuel

[MalcQV]

On my Alfa it would get to about 50 miles and then wouldn't give you a range
23 is the lowest on my CLK. I always go full to empty. A full tank (bigger) in the Alfa would to last 1½ - 2 weeks whereas this just a week.

 

[turbopete]

More that the crud gets stirred up though - wasn't referring to the pick up...
Similarly never fill up when a tanker is in there or you've just seen him been

again, another myth. theres very little crud in fuel nowadays anyhow and unless your running some old carb fed 80s model, theres CERTAIN to be a fuel filter between the tank and the engine so it CANT really cause issues (unless the filter hasn't been changed in 100k miles+) the issue many moons ago was bits of crud blocking the jets in carbs. those days are gone by at LEAST 25 years (unless you have some classic or kit car running carbs) and even the handful of bikes still running carbs have fuel filters.

 

[LostKiwi]

More that the crud gets stirred up though - wasn't referring to the pick up...
Similarly never fill up when a tanker is in there or you've just seen him been

But that makes no difference surely. If it did we shouldn't drive anywhere after filling up from a nearly empty tank. Personally I have never had an issue with driving to low fuel levels and I've done it regularly throughout my life.

 

[peterws1957]

I had a Focus the fuel computer of which ran down on a mile by mile basis. It once proved unnervingly accurate when on a very snowy winters day I didn't want to stop on the way home and it turned to zero and the car conked out as I turned onto my drive. Very silly thing to do but I had 5 litres in the garage and I knew from then on I could rely on it to give an accurate reading.

 

[Craiglxviii]

Right... so the reading on a fuel gauge is never linear whatever it might seem.

The bottom end is always drawn out. When it reads zero (and when the low fuel warning is lit) the car will be telling you 40/50 miles (plus a margin which won't be disclosed). Now how far that undisclosed margin will get you is heavily vehicle-dependent, but it's usually another 2-3 litres after the gauge is pegging on zero.

 

[Craiglxviii]

But that makes no difference surely. If it did we shouldn't drive anywhere after filling up from a nearly empty tank. Personally I have never had an issue with driving to low fuel levels and I've done it regularly throughout my life.

Look at the pickup inside the tank. It sits around 20-25mm proud. So, the pickup is always taking in fuel from the lower level of the tank regardless of how full it is. That's why it doesn't matter.

 

[John Laidlaw]

Look at the pickup inside the tank. It sits around 20-25mm proud. So, the pickup is always taking in fuel from the lower level of the tank regardless of how full it is. That's why it doesn't matter.

Sloshing sir......

 

[raymondj]

There's a myth as the pickup in the tank is at the lowest point on the tank anyway!

Interesting info

 

[raymondj]

I have been in the same position a couple of times. Once it shows 40 miles I reset the trip knowing I have 40 miles left.
In practice when I filled up some 20 more miles down the road there was at least 5 Ltrs left in the tank. So the reading is very conservative.

Again, good info and thanks

 

[nicholas15]

The range calculation seems to work almost in real time based on the mpg from the current driving conditions. So the range can drop considerably after a couple of minutes heavy right foot and then improve significantly a couple of minutes later if you revert to a steady cruising speed.

Frequently drivingback from London I have arrived home with a greater range than when i set off in London. It still amuses me to see range increase when i start driving on a motorway after in town driving. Five miles in and range has increased by 10 miles. Magic, must be use of the premium fuel.

 

[sonic]

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[sonic]

My E350CDI in Germany a couple of years back. First time I have seen 40C in Germany.


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[JT1]

On mine, (W213) and the last one (R172) and in fact on the one before that - a Volvo C70 - the range is replaced with a "Fill up now" (reserve fuel, whatever) message when it goes below a certain distance remaining (when the fuel warning light comes on)

 

[oigle]

My cars are so old they don't have computers but I did exactly as I suggested and the W124 went for over 60 miles after the warning light came on. Not tried it with the R129 but they are very conservative with their warnings.

I'm sure they are VERY deliberate in their conservative readings. Can you imagine the HOWL that would go up if cars ran out of fuel with the gauge saying it still had some.......safer to be the other way.

 

[EmilysDad]

On mine, (W213) and the last one (R172) and in fact on the one before that - a Volvo C70 - the range is replaced with a "Fill up now" (reserve fuel, whatever) message when it goes below a certain distance remaining (when the fuel warning light comes on)

When my last car went down to 50 miles to go, the display then defaulted to 'range' from whatever it'd previously been displaying .... my Merc doesn't, which IMHO defeats the object.

 

[turbopete]

When my last car went down to 50 miles to go, the display then defaulted to 'range' from whatever it'd previously been displaying .... my Merc doesn't, which IMHO defeats the object.

mine also defaults to range at a certain point (about 40-50 miles left)

 

[LostKiwi]

The Smart defaults to litres left when there are less than 5.5 in the tank.
I've run it down to 0.5 before now...

 

[ajlsl600]

i had a car once 504 saloon that would not run right at high power settings, after about 3 days i found the fuel pick up pipe was not cut at an angle we had driven over some mud and the tank had been pressed up against the flat bottomed pick up pipe, ok at low power as enough just leaked through the gap,but the motor was starved at 120 kph and would not run much above 30 kph . that was a bugger to find. ,saw 8mm circle impression on tank bottom ..............eventually..

 

[John Laidlaw]

again, another myth. theres very little crud in fuel nowadays anyhow and unless your running some old carb fed 80s model, theres CERTAIN to be a fuel filter between the tank and the engine so it CANT really cause issues (unless the filter hasn't been changed in 100k miles+) the issue many moons ago was bits of crud blocking the jets in carbs. those days are gone by at LEAST 25 years (unless you have some classic or kit car running carbs) and even the handful of bikes still running carbs have fuel filters.

Cheers that's me told!

 

[turbopete]

Cheers that's me told!

sorry if it sounded harsh, it wasn't intended. every car petrol or diesel has an in tank strainer. then a fuel filter (some will even have a pre filter, like the 210/202) then some diesels even have another filter where the pipe enters the high pressure pump. on even the most basic set-up, theres at least 2 filters between the tank and the engine. now, back in the days of carbs, many cars didn't have ANY filter (other than a tank strainer which isn't that fine in some cases) and in very rare occasions, a strainer across the feed pipe into the carb. this stopped larger parts, but I remember cars having to have the jets blown through with the airline to clean the carbs out! fords had no actual fuel filter (as in a changeable one, unless they were diesel or fuel injected) for example, so some people fitted them as an addition, if their fuel was coming from a tank at home (farming area) or similar where the tanks could get rust and crud in them over time as the fuel didn't change that often (a tank may last a year or more whereas a filling station will need refilled every few days) so whilst this may have been an issue in the 60s and 70s, (even the 80s to a degree on carb fed cars) fuels are now cleaner (from crud) and stored in cleaner, improved tanks (so less of an issue to start with) then filtered multiple times in the car before use. its also a fact that over time, the aspect of tank safety and environmental pollution has meant that instead of having rusty metal underground tanks at petrol stations that were never changed until it was realised that they were leaking (fuel going out meaning crud could get in) tanks have to be tested after a certain age and bunded (double skinned, basically) so than any leaks are contained in an outer skin.