'AVG MPG' - shows something else before engine started

[andrum99]

I've got a 66 reg Aygo which I've owned since 2018. The multi function display in the middle of the dashboard shows something that is not explained in the handbook. I leave the display on the 'AVG MPG' reading most of the time, so when I get in the car and start the engine I expect it to show that - at present it is 62.1. What actually happens is that when I turn the ignition on (it is a basic model with keyed ignition) the AVG MPG display shows 4.6 instead. Once I start the engine, after a few seconds the display changes and it displays the actual MPG figure. Can anyone possibly explain what the other number is?

Attached are some pictures so you can see exactly what I mean:

1. Odometer displayed after opening the driver's door and before inserting the key.

2. After inserting key and turning to ON, AVG MPG is displayed, but shows value 4.6, which is what I don't understand.

3. After starting the engine, after a few seconds 4.6 changes to 62.1, the actual fuel consumption figure.

Any ideas? 🤔

[yossarian247]

Is it briefly showing the fuel consumption in litres per 100km before reverting to MPG?

It's not quite bang-on, but 4.6 L/100km is just under 62 MPG.

 

Edit: 62.1 imperial MPG equates to 4.55 L/100km, so if the display is rounding 4.55 up to 4.6, there's your answer.

[andrum99]

Many thanks - that looks like it is the answer. I wonder why it's doing that? Presumably for cars sold in countries where a metric fuel consumption figure is commonly used, the display says 'AVG L/100km' or something similar, instead of AVG MPG.

[yossarian247]

In my days of Volkswagen ownership I remember that the fuel computers on those calculated the fuel consumption in L/100km behind the scenes, then apparently had an extra little piece of software to turn it into MPG in the dash display for UK drivers. It seems like your Aygo is perhaps doing the same thing.

[andrum99]

I see - thanks for the info.

[Cyker]

The mpg stuff is often an after-thought; We're the most awkward country to build cars for in this area - We use different distance and speed measurements to everyone else nearby and are also the only ones with the steering wheel on the right!

The road sign thingy in my Yaris still thinks the signs are in kph most of the time  

With all the computers you'd think it would be trivial to add unit conversions but apparently car companies are still not very good with software, so it doesn't surprise me to hear there's some glitches...

 

[Wiz201]

Australians have right hand drive cars though?

[mrfixer]

4 minutes ago, Wiz201 said:

Australians have right hand drive cars though?

I can't think of any other countries that use miles per Imperial gallon for fuel consumption.  There are plenty of other RHD countries (Ireland, Aus, NZ, Japan, Malaysia, Thailand etc) but all use km and litres.  My Yaris in Thailand has an on-board computer but can only show km per litre or litres per 100km, no facility to show mpg.

[Mjolinor]

It boils down to when that crappy metric system was forced onto normal people by governments with not enough brains to see how crap anything metric is. 🙂

 

 

[Cyker]

Nooo metric is great! If I had to go through GCSE and A-Level science using imperial units I would have shot myself - The conversions are sooo much easier with metric! Everything just fits together, it's so elegant!

I do prefer imperial units for 'human' measurements - Anything that needs a rough measurement or ballpark figure just 'feels' more intuitive with imperial - About a mile, a few pints, a couple inches etc., but you can't beat metric when you need accuracy and conversions.

 

 

6 hours ago, Wiz201 said:

Australians have right hand drive cars though?

They do, but they get their cars from Japan, who are also RHD - I think we're (Edit: and Ireland!) the only RHD country served by the eurozone Toyota factories...

I am just thankful they don't compromise the cars like a lot of manufacturers do - e.g. I found the RHD version of the Zoe basically doesn't have a glove box vs the fairly generous one of the LHD model, because they couldn't be bothered to relocate the fuse box for the RHD model, and IIRC there was a car where the pedals and steering linkage went through some ridiculous path because they only designed it with LHD in mind, and only much later realized there was all this stuff in the way for the RHD model, but again couldn't be bothered to redesign it properly, so just put in a very failure-prone bodge instead.

 

[Rhymes with Paris]

Nooo metric is great! If I had to go through GCSE and A-Level science using imperial units I would have shot myself - The conversions are sooo much easier with metric! Everything just fits together, it's so elegant!

 

I do prefer imperial units for 'human' measurements - Anything that needs a rough measurement or ballpark figure just 'feels' more intuitive with imperial - About a mile, a few pints, a couple inches etc., but you can't beat metric when you need accuracy and conversions.

 

I dunno, give 'em about 25mm and they'll take about 1600 M.

Back when I was in your neck of the woods, the construction drawings were dimensioned in both imperial and metric , sometimes at the same time.

You are right though about human measurements,in the news you often see,the length of 3 buses,or the size of 2 football fields.

I must go out and measure a bus and a football pitch,as I have no idea what they are, but I know the length of a 30M tape measure.

 

 

[Mjolinor]

Compared to other base units ten is about as hard as it gets. Ten is divisible by two and five, 12 by 2.3.4.6. 16 is better still, that is why computers use it.

Imperial units are usually base 12 or a multiple of it making mental arithmetic much easier in all cases, sometimes they are base 16 as in lb and oz..

For sub unity measurements the Imperial system becomes essentially a binary system with fractions being halved or doubled for example half of 3/16 is 3/32 and so on. That is the way it was used in engineering for ever.

Base 10 was not accepted as a measurement for time even though it was made illegal to use base 12 when Napoleon introduced the base 10 clock in France along with the other metric crap that we are forced to use today.

Apart from the most basic stuff Imperial wins as an easier system for working with. There is absolutely no logic to a base 10 system at all. Any system based on nothing can never be better than a system that is based on real world need.

[Cyker]

That's an interesting take on it - Never heard the argument for it like that before! Food for thought!

What I like about metric is less so the base but how all the units fit together - You need so many different conversion ratios with imperial units, but everything just fits in metric.

I do find sub-decimals much easier to work with than imperial fractions tho'!

One small correction - Computers don't operate on base 16, they operate on base 2; Base 16 is a handy representation for us tho', as it's a lot more convenient than loads of 0's and 1's!

 

[Rhymes with Paris]

That's a good point Mjolinor, and very well explained.

I was on the cusp of the imperial to metric conversion in this country,in around 1970.

So had to calculate a lot of conversions from one to the other,in fact I still find it difficult to think how a loaf of bread can now cost upwards of £3 12 and 6 pence.

[Mjolinor]

12 hours ago, Cyker said:

One small correction - Computers don't operate on base 16, they operate on base 2; Base 16 is a handy representation for us tho', as it's a lot more convenient than loads of 0's and 1's!

Yes the computer uses binary but to make it human readable it is presented in base 16

Yes the computer uses binary but to make it human readable it is presented in base 16. I was talking about usability for humans, that is what measurement systems are all about.

[Puglet]

Same here I was one of the 'confused' youth, at school was full on metric, at home my dear old Dad as still measuring, cutting, fixing in 1/8ths and 1/16ths. As the 'hired' help I was occasionally allowed use his rule, but often got it wrong, so stuck to lifting and carrying.