Fuel consumption always reads the same

[Graham Duro]

Hello everyone. I have a 2020 2.0 litre Corolla Touring Sports Excel and the fuel consumption readout is always 49.8 mpg, regardless of distance driven, speed, etc. I've reset the figures  but it immediately reverts to 49.8. 

Am I missing something, or does this mean a trip to the dealers?  

Thanks in advance for any help.

[Obsidian Estate]

I always work mine out myself. They always fib anyway.

[dee123456]

Do you reset it everytime you fill the car up? I do and mine always changes depending on where i go.

[AndrueC]

Is it set to 'total tank average' rather than 'trip average'? If you've had the car long enough I can imagine that 'total tank average' doesn't change very much.

[Roy124]

3 hours ago, Graham Duro said:

 

Am I missing something, or does this mean a trip to the dealers?  

How much does this mean to you in cash terms? 

What reading do you get from the App? 

I don't know anything about the system but if they are the same it might suggest a computer fault. 

[Graham Duro]

1 hour ago, dee123456 said:

Do you reset it everytime you fill the car up? I do and mine always changes depending on where i go.

i usually reset it before a trip.

[Graham Duro]

38 minutes ago, AndrueC said:

Is it set to 'total tank average' rather than 'trip average'? If you've had the car long enough I can imagine that 'total tank average' doesn't change very much.

I wasn't aware of that option. I'll look tomorrow. Many thanks.

 

[Roy124]

Andru's question might be the answer though reading precisely the same 49.8 suggests something else. 

I accidentally reset mine (total average) while driving.  It immediately shot to 99.9. As I applied gas it dropped to 50 or so, next coast phase back to 99.9

After a few miles it settled nearer 80.

A bit later it started to give a realistic average of nearer 70.  

Now, driving carefully I can nudge it up in 0.1 increments.  Later in the year it will drop down. 

As I asked earlier, what reading does the App give? 

 

[TonyHSD]

Whatever settles the dashboard after some time of driving it is most likely the realistic numbers that the car actually consumed over that time. You can double check with filling up full twice and see if there are any difference, my car is spot on correct . 👍

[Roy124]

Graham, I say again, do you get the same result on the App? 

[frizzbee30]

On 6/30/2022 at 6:39 PM, Obsidian Estate said:

I always work mine out myself. They always fib anyway.

Actually,  no they don't. 

 

Fuel metering is exact, guessing fill point to fill point, isn't. 

 

It's pretty obvious that you aren't from a science or engineering background..🤣

[Obsidian Estate]

Guessing?

Ok mate 👌🏼

[yossarian247]

19 hours ago, frizzbee30 said:

Actually,  no they don't. 

 

Fuel metering is exact, guessing fill point to fill point, isn't. 

 

It's pretty obvious that you aren't from a science or engineering background..🤣

You'd think so, but whatever software turns the fuel metering data into a dash MPG readout is far from exact in many cars. I've compared long term actual fuel consumption versus fuel computer display consumption in a variety of cars over the past 15 or so years and the dash MPG readouts are frequently +/- 5-10% out. The MPG display in our Avensis for example has always been around 8% pessimistic for all of the years we've owned it. Conversely the MPG display in a Skoda Octavia TDi I used to own was consistently 7% optimistic, that is until I tweaked it with VCDS to make it accurate. VW Group even acknowledge the inaccuracy of their own fuel consumption displays from the factory and allow dealers (or anyone with a VCDS cable) a means of adjusting the readout by a specific percentage to make it correct.

[AndrueC]

Most vehicles don't use fuel metering anyway. They count the frequency and duration of injector bursts and use that to estimate fuel consumption. That's the main reason dashboard displays aren't ever accurate.

A separate issue is the distance travelled is measured by counting wheel rotations and as the tyre wears and pressure changes the circumference will also. Thus the mpg is almost always calculated wrongly anyway whether it be calculated by the car or the driver.

[Cyker]

Don't worry, they're just trolling

[Tech429]

You should be able to set how you want the readouts to be on the MFD - I think you have the choice of "every fuel fill up" or "Every trip" and possibly others too.  

Mine is set to show me on the MFD every trip as i am not one for doing a tank check unless i decide to do it every so often.

[Roy124]

Graham has not been here since Thursday 

[Parts-King]

I actually take a look at these MPG threads and snigger to myself the way people get very upset about their MPG

The car is a mass produced product, made all the same, to fine tolerances. THE most important factor in getting better MPG is the driver and the quality of the fuel

The way people get all heated over "My car is only doing X miles per gallon and yours is doing Z" or the other hilarious thread is "The range shows XYZ miles but that can't be right coz it does ABC to the gallon bla bla bla" I have a tip for anybody worried about range or if you are getting only 60 to the gallon when Joe Boggs gets 65................

Just fill the ruddy thing up when the car gets down to quarter of a tank, fill it, don't put £3 of fuel in and not see the range move

There, fixed it for everyone, your welcome  

[Cyker]

...

My tank average says 84mpg today!  

*ducks*

 

[Yorkie21]

My 2.0 averages 54-55mpg over a prolonged period and closely matches the figures from a fuel management app I use (‘Gas Manager’). It’s normal to have a lower mpg figure in the winter, motorway speeds hit the economy a bit too.

[Kental]

I’ve only got 50.4 mpg since I got my Corolla on Saturday. However in the car’s defence part of my journey from Lincoln to Kent was via Germany as the adaptive was set at 80 mph. Less than 3k revs so hardly stressing the car. Today I had a lift in a 71 plate TS taxi. 69 average including motorway work. Also my commute home I got 62.2. Clearly the 50.4 is my right foot’s fault not the car.

Assuming as my car still only has 275 miles on it, the economy will improve or are engines so well  bench tested these days, the economy doesn’t increase?

[TonyHSD]

7 hours ago, Kental said:

I’ve only got 50.4 mpg since I got my Corolla on Saturday. However in the car’s defence part of my journey from Lincoln to Kent was via Germany as the adaptive was set at 80 mph. Less than 3k revs so hardly stressing the car. Today I had a lift in a 71 plate TS taxi. 69 average including motorway work. Also my commute home I got 62.2. Clearly the 50.4 is my right foot’s fault not the car.

Assuming as my car still only has 275 miles on it, the economy will improve or are engines so well  bench tested these days, the economy doesn’t increase?

You may see a slight improvement in fuel consumption as a result of engine been run in after the first 1000 miles but the greater margin in fuel consumption comes from you adapting the new driving style and technique that suits more the hybrid cars. Pulse and glide and anticipation ahead. Once fully adapted even you return to a standard petrol manual you will still be getting better mpg than before 👌👍

[Roy124]

Regarding Kental getting 50 mpg with ACC set at 80 mph (or 80 mph?) that is actually quite good.  My mpg dropped to less than that on a high speed run down the M5 and A30 to Bodmin.  The weather was dreadful, the car was loaded and I was pushing 75 indicated. 

I am doing the same journey next week, I will aim at 55-60 true.  If traffic dictates I may go up to 70 indicated.  In my experience the majority of drivers drive at 70 indicated. 

[Roy124]

Parts-King up thread mentions fuel quality.  Yesterday Sainsbury (cheap) was priced at the same price at Shell E10. 

Given the price per litre today, by putting in only £10 per time I can both reduce the running weight of the car and with a Shell car get £1 after 10 fills.  It is only 1% but close to one fill at 2p/l discount.