Fuel gauge dies/drops to nothing Xantia hdi

[andy5]

My tank (series 2 HDI SX) holds more than 65 litres - in fact I just broke my fill record, 77.73 litres. Range on tankful 700 to 900+ miles.

So if yours is similar you may have been still around 1/4 full when you added 57 l

[Harlequin]

Depending on your driving style, that could be showing as correct anyway. The 2 litre HDi gets 60mpg on a run so 65 litres is over 800 miles to a tank

[ashy90]

Well mine seems to get 42.5mpg pretty much all the time.

So when it took 57.5 liters of fuel to fill it up, there could have been more than 7.5 liters of fuel remaining in the tank?

[Harlequin]

60 is on a motorway, does drop for `extra urban`

[ashy90]

Yesterday I checked the resistance of the two new pumps and they are pretty much identical. So now I am thinking there wasn't actually anything wrong with the first new pump (PWM).
Moving the float arm through its full range they both measured pretty much the same at their min and max and had no dead spots that diddnt read etc.
.346 (empty)
.050 (full)

So I am thinking either I had a float problem, or there was just way more fuel in the tank than I thought (which means it holds considerably more than 65l)

The reason I mention the float........the float on the original faulty pump (with dying fuel gauge) faced a different way and the arm was a different shape, to both of the new pumps (both new pumps were the same however).
The first new pump (PWM) actually had a damaged/chipped float, so I swapped over the float from the original faulty pump to the new one then fitted it. So I wonder if it was this, the old float (facing a different way) on the new pump that was causing it to over read.

Time will tell with the new Bosch pump fitted!

[myglaren]

My C5 is a 65L tank and I can get 72L in it, maybe more.

[admiral51]

Being an old git and with a very healthy disregard for official figures can i just say this given the recent emission problems by a number of manufacturers.

Prior to the introduction of digital MPG figures being available in car if a car was tested ( assumption it was full ) for media reports then they would fill it up on return, check the mileage against fuel used and come up with a MPG figure.
Now if the manufacturer states it holds 65 litres, it was full when you started and you filled it up on return, you base your figures on that info.
Now if it holds 80 litres your MPG figures are going to be a little bit out, but we trust the manufacturers right

[ashy90]

I was working the mpg out by seeing how many miles I have covered and how many litres of fuel used.
I always fill it to the max until the pump cuts off (once) and then rest the trip. When I fill up I look at how much fuel it has taken to fill it up.

[myglaren]

I was working the mpg out by seeing how many miles I have covered and how many litres of fuel used.
I always fill it to the max until the pump cuts off (once) and then rest the trip. When I fill up I look at how much fuel it has taken to fill it up.

I have run a spreadsheet for that since 2007 - actually before, but dumped it when the Accord went in favour of a C5.
Depressing reading.