Completely Stupid Average Mph Values

[jayteepics]

Short or long trips it doesn't matter I 'apparently' only drive at about 21 or 22 Average MPH (been reset at each trip start - some trip mileages have been over 200 miles including motorway at high speeds)

Anyone had such stupid values? Is this perhaps a software update required?

[MarksST]

Mines usually on about 24, it's normal, unless you can drive at a high speed constantly it will be low.

[iantt]

quite normal when you realise its time and distance calc, alot of times in town slow or staionary, even on normal roads you can expect to stop or slow for bends, turning off one road to another etc etc, that then gives low mph,

i travel 9 miles to work and im doing 50mph most of journey , but travel from one town to another with multiple lights at each.

so it takes me minimum 20mins or more so av 27mph max

if you think its wrong, just double check mileage against time taken on your next journey.

[jayteepics]

Guys thank you for your quick and simple explanations.

My previous Focus [55 reg] showed a much higher AVG. MPH... IIRC

[negendahl]

Mine is currently around 45MPG, not driving particular economical, haven't been reset in a while.

Normally if i only do highway around 120kmph - 130kmph i get around 47-51MPG - pretty good considering its a small 1.0 engine.

[Mariner]

My average MPH is around 30 (I commute 40 miles round trip a day on mainly dual carriageway)

My average MPG is around 48 with AC on and 50+ with AC off.

[StevenST13]

My ST is averaging 38mpg that traveling 9miles to work and 9miles back on a mix of 30,40 and 60mph roads. On the motorway I can get it to 45mpg at a steady 80mph. Even town driving it never drops below 32mpg but I've always run it on Shell or bp fuel never the supermarket crap.

[MarksST]

It's nice that you're getting good MPG but, it wasn't what the OP was talking about, lol.

[iantt]

It's nice that you're getting good MPG but, it wasn't what the OP was talking about, lol.

I was wondering also if the topic was wandering off subject.lol

[StevenST13]

I miss read the post 😖. My average mph is between 18-22 but I've never really taken any notice of tbf as I can't c the point of it.

[Mark M]

Could always reset it as you start on the motorway and check it before you leave, should be up around 70 then.

[Overland]

My previous car was a Fiat and its average mph was 27 (rural and a little city work), cancelling the milage trip also cancelled the fuel and average milage. On my Ford it seems that I have to cancel them independently (well that's what I have been doing), with its quick pickup and go our average mph has come up to 29 mph over 800 plus miles. For the previous 500 miles (all done in one journey mostly dual carriageways), it averaged 50 mph and 55mpg. I never saw those figures with the crappy Fiat as it always felt that you had to work hard to go anywhere.

[elanmac]

Don't rely on the onboard computer for MPG or MPH they are both likely to be upto 10% optimistic. My MPG was showing 48, but by checking the actual amount of petrol that I used it worked out at 42 MPG not good. Even that is probably wrong as the milage works off the same pickups as the speedo. If that makes sense.

Mac

[Overland]

I agree that there is a discrepancy between the actual mpg and the mileage, on our car mpg is mostly fairly close to reality (this is assuming that the miles on the clock are accurate). Recently I did a long trip and, compared to our previous car (a Fiat), the actual amount of fuel used by the Ford was considerably less but the mpg display was showing that we had used about the same. I don't know how the computer works out the mpg, but the Ford maxes out at 99mpg on overrun and Fiat maxed out at 142, does the computer take these figures in to the calculation? The Ford and the Fiat have speedos that read around 2 to 3 mph above the actual figure (according to roadside speed indicators and our sat nav). Computer systems are OK while they are working reliably, but they can leave you in a real muddle when they fail. Just before I parted with the Fiat I was doing an emergency run in it and the display said I had around 140 miles worth of fuel left but only 12 miles down the road was telling me I was out of fuel, I got another 10 miles before the engine started to surge indicating that I was about to run out of petrol, luckily I did make it to the nearest petrol station.

David

[David73]

I don't know how the computer works out the mpg, but the Ford maxes out at 99mpg on overrun and Fiat maxed out at 142, does the computer take these figures in to the calculation?

Instantaneous and average will be different bits of maths.

I haven't looked at instaneous in enough detail but it probably looks at fuel used and distance covered in a 2 second period. The maths has to deal with a varying number of injector pulses (*) and turns of the driveshaft according to power and speed. On overrun when no fuel gets used there will be a division by zero so it just shows 99 or whatever, as the highest number the display supports.

The average is simple, totting up total fuel used and total mileage covered. It doesn't care about time and it won't be (or shouldn't be) integrating up all the instantaneous readings.

(*) The fuel measurement comes from the ECU which knows how much time the injectors spend open and assumes fuel passing through is in proportion.