Fuel Economy.

[Welly]

I have a tip - when embarking on a 'test mpg' run then reset the fuel computer and let the average settle down to a steady reading for 'that' journey (this can take 45 mins or so).

The accumilated daily average takes f*cking ages to change and it won't even reward you after 100 miles or so.

[mjb]

The accumilated daily average takes f*cking ages to change and it won't even reward you after 100 miles or so.

It's called mathematics, and the general fact that it's easier to burn fuel in a car than not

If you drive 100 miles at 50mpg, you'll use 2 gallons of fuel.
If you then do a whole mile without using a single drop of fuel your average will then be 101/2=50.5mpg, just 0.5mpg difference

However if you've got a V6 and do that last mile at 4mpg (thus using 1/4 gallon in that mile)... your average will drop all the way to 101/2.25=44.9mpg. Ouch.

[richofwilts]

Hi All

I have just bought a 52 reg 406 2.0 hdi (110) auto and are disapointed with the fuel economy. The on board computer says we are averaging 35 mpg is this about right ? I was led to believe it would do about 42 mpg.

[Welly]

Hi All

I have just bought a 52 reg 406 2.0 hdi (110) auto and are disapointed with the fuel economy. The on board computer says we are averaging 35 mpg is this about right ? I was led to believe it would do about 42 mpg.

Unfortunately the slushmatic gearbox will sap 3 to 5 mpg

My manual 110 HDi has dropped to 38.2 average in this colder weather (was 42 in summer).

Oh, get the auto box fluid changed it's a great preventative maintainance job and far cheaper than a new box ££££££

[richofwilts]

I did think about changing the autobox oil but I was told that the gearbox was sealed for life ?
How accurate are the on board fuel computers ?

[mjb]

How accurate are the on board fuel computers ?

Very - at least on the ones I've had