Avensis Tr 1.8 Valvematic Registered March 2009

[jayfree]

Hi Guys

I have a problem which seems difficult to fathom ( unless I am having one of my funny turns ! )

The fuel capacity of my car says 60 litres (or in old money 13.19 gallons)

The Car Book says that my combined mpg should be 42.8 mpg

( ie a mix of Urban 32.8 and Extra Urban 51.4)

Therefore should'nt my Dashboard Display read 564 as the range on a full tank ? based on the combined figure.

How come it only ever reads 360 or thereabouts ?

Am I that daft that or am I missing something here or is it that I am simply not reading this correctly.

If anyone can enlighten this silly old s--, I would be grateful.

Cheers

[mintalkin]

i think the computer works out the remaining miles from what your currant average mpg is times fuel left in the tank

[Whitewagon]

The manual gives you the official fuel consumption figures as tested under EU regulations. That figure is not transposed into the computer i.e. a full tank of fuel does not register a figure of 564 miles left but is based on your current useage. The computer figure is seemingly based on the average mpg you are getting and possibly the variation in driving style and speed.

The EU figures for mpg are not real world figures and though, in ideal conditions, you may get close to that figure in general you will get less. All the electronic readouts are likely to vary from car to car. For a real world test of your readouts reset all the data in the computer and then do a few brim to brim tests to see how accurate the readouts are.

Check the below site for a guide to real world figures:

http://www.honestjohn.co.uk/realmpg/toyota

During warm weather I get 38 mpg but during the recent cold spells this has dropped to a fraction over 36 mpg. Both figures are less than the official figure of 42mpg.

[jayfree]

Thankyou for your response to my question but I regret that I cannot really work out what you are saying.

MY point is ...that when I have filled the tank , the readout gives me a Range. Which to my simple mind is the number of miles

that , that amount of petrol will enable me to travel without having to fill up again.

Other wise what is the point of telling me what the range is.

Anyway I appreciate you taking the time to reply.

[jayfree]

Thanks again for that reply Whitewagon.

I have to refer back to my simple mind and pose the question " what is the point of the car showing the range of miles that you can go when the tank is full , if that range figure or amount of miles it gives , is wrong or incaccurate.

It seem to me that, it is worthless information. Because my simple mind stil dos'nt know if I can travel 560 or 360 miles ( or anything else) before having to fill up again.

I would not expect you to reply again if you feel that you are dealing with a cretin !

Thanks and best regards

[t-spiritpete]

Hello, the answer to your question is not straight forward.

I think the computer takes the worst case or lower figure say 32.8mpg then computes how many miles that the car will travel before the fuel light comes on, there may still be 2 gallons left in the tank at that moment so that would be 11 gallons used at 32.8 mpg which = 360 miles and if you did all your miles in the city then that would be the case, computer correct give or take a bit.

Once you have filled up and traveled a good few miles on the motorway at 70mph then the computer may well show you a higher range after all the computer doesn't now how the car is going to be driven over the next tank full.

On average my cars computer is about spot on over all, I have filled up and it said 450 miles range then I may go on the motorway and get 600 miles but all town driving I get 440 miles before the warning light comes on.

Regards Pete.

[jayfree]

Thanks Pete

I understand what you are saying and appreciate it. It does now sound somewhat clearer and I am grateful for your explanation as indeed I am of the other contributions from the other guys.

The moral of the story seems to indicate that when going on a long journey , disregard the Range figure and keep an eye on the petrol guage.

So my concern is over and I really appreciate the opportunity of once again having the very good fortune of being able to get the advice of you guys.

good luck.

[Whitewagon]

More than happy to reply.

You are confusing what Toyota has said the car will do as to opposed to what it actually will do to the gallon. This is further compounded by the fact that the distance you can actually cover per tank full will vary according to several variables such as the speed you travell at, how hard you accelerate and even the outside tempurature.

The readout will change as you drive. For example you can fill up and the reading will be 500 miles because you are stationary. As you drive off you join a dual carriageway where for 20 miles you drive at a steady 50mph. The computer will work out and display what mileage you can cover according to that speed and the steady throttle opening. You then enter a large urban area where you are in heavy traffic and constantly starting and stopping, this type of driving will probably cause you to use more fuel than driving at a constant 50mph. The computer will recognise this and alter the range you can travel accordingly. You then get to the motorway and because you are now running late because of the last traffic situation you decide to risk it and drive for an hour at between 80 and 90mph. This is not fuel efficient and will cause the computer to recalculate again and give a different readout. The computer constantly recalculates how many miles you can travel according to your driving conditions at the time and how many miles you have covered.

So there is value in the readout, it tells you how far you can go on the fuel you have left, if you only take the full tank reading as your guide you could, and probably will, run out of fuel before reaching that figure. What the readout actually does is remedy this problem by giving a constantly variable readout so that you will know how far you can actually go before filling up again.

Hope this makes it more understandable.

[jayfree]

Thankyou again Whitewagon

Yes, that is much clearer and I can now understand how the system works . I am much happier about it and am grateful for the comprehensive explanation.

Iam really very much obliged.

all the best

jayfree

[cooper12000]

from what i have found it goes on ur average mpg . the reason for this is everyone drives differntly and people would soon complain if the range said they had 200 miles left but they were conked out on the side of the road having run out of fuel. likewise people would complain if the range said zero but the fuel light hadnt come on because u still had fuel left.

hope this makes sence coop

[jayfree]

Yep, I think I get your your drift Coop .Thanks very much for that .

Mike sort of wrapped it up for me quite succinctly I thought so with all the info I have received I am now quite happy.

all the best.

jayfree