"Average MPG"... Or is it?

[jmurray01]

How does your car's computer fair when it comes to calculating the MPG? Of course this only applies to cars fitted with computers and doesn't have to be Volvos.

Our 2005 Nissan Primera 1.8 petrol does quite well on averaging the fuel consumption, although the "distance to empty" is way off, but in fairness it goes by the reading given to the fuel gauge and it itself is too pesimistic, so it is being as correct as it can be.

The last fill up ocurred at 520 miles and took 54 litres of unleaded to fill to the brim again, therefore the average MPG for the tank used was 44MPG - whilst the computer said 41MPG! Not bad at all for a 10 year old petrol engine with almost 200,000 miles covered over its life.

At that point (where being a 62 litre tank it had over 8 litres remaining) the "distance to empty" was at zero and the fuel guage was bang on the empty line. Of course, a further 40-odd miles could easily have been covered, but that's the way with most fuel gauges, gotta prevent the stupid people from running out I guess!

So, from my experiment with the Nissan it attained 44MPG whilst the computer said it was averaging 41. Not bad really, if a little negative! Better that way though as I've heard of some cars claiming in excess of 50MPG whilst they were guzzling it back at a rate of 35!

I gotta say though, I'm loving the 40+ MPG again! The V40 was a great car but with an average of 31-33MPG I was not impressed considering it was only a 1.8 and with the auto transmission it had the same amount of power as a 1.2 manual.