Full Fuel Tank (Theoretical Mileage)

[agent_dess]

Ok can someone please put me out of my misery!

for the last 6-7 times that i filled the tank with petrol, i always check the fuel tank capacity and it always reports as 377 miles....

I always refuel when the tank is 1/2 empty.

Now im sure when i first got the car and filled it, it stated 400 miles.

I had the 60k mileage done in January 2013 by Lexus.

Can everyone tell me what their IS250 fuel tank reports as please?

[dave1]

The figure will vary as it is based on your previous fuel consumption and as such is not a true guide as to the mileage that you will get from the tank of fuel.

[agent_dess]

Well according to carpages:

http://www.carpages.co.uk/guide/lexus/lexus-is-250-se.asp

Theoretical Range to Empty is 476-480 miles

Surely when you fill the tank the display is rest and it should quote something along the lines of 476-480!

I just want to know what other drives report when they fill the tank a couple of times...is it consistent?

[dave1]

Not really. The figures quoted on carpages give the theoretical range if you are getting the manufacturers claimed combined mpg....using tank capacity x fuel consumption. Yours should be using ACTUAL fuel consumption not "claimed" figures.

[dazed]

As others have said, the display is an estimate based on actual driving, not theoretical driving and will therefore tend to settle down to a number based on the type of driving the car experiences.

One point to bear in mind is that when the display reaches zero, you have about one gallon left in the tank, so theoretically your total range is about 30 miles greater than the number displayed. But I wouldn't recommend relying on that.

My car usually states a range of 430 miles after a fill up giving a total range in the region of 460. This equates to about 33mpg which is about right in my experience.

[ronsis]

i'm currently running at 42 around town/comutting.. and had 51 on the motorway at 70 on cruise... (400miles) i'm happy. must be my scottish tight right foot... ;op

(actual figures 43l for 395miles around town/comut/etc..)

( i do my own calcs based on filled tanks/millage... the vehicles trip comp.. isn't far off though...)

[agent_dess]

On a full tank I get between 39-42 mpg... All other times i get between 31-33 mpg.

I drive 50 miles everyday.... All motorway at 65-75 mph

[dazed]

On a full tank I get between 39-42 mpg... All other times i get between 31-33 mpg.

I drive 50 miles everyday.... All motorway at 65-75 mph

I'm confused. How can the amount of fuel in your tank possibly affect your fuel economy to that degree?

[dave1]

On a full tank I get between 39-42 mpg... All other times i get between 31-33 mpg.

I drive 50 miles everyday.... All motorway at 65-75 mph

Where are you obtaining these figures?

[agent_dess]

On a full tank I get between 39-42 mpg... All other times i get between 31-33 mpg.

I drive 50 miles everyday.... All motorway at 65-75 mph

I'm confused. How can the amount of fuel in your tank possibly affect your fuel economy to that degree?

Clearly the machine is lying to me lol :p

I just go by what the obc displays... I always reset the mpg display every time I fill up by holding the button for 1 sec...

What i will add from my observations is that I always manage 250 miles from 1/2 a tank...

I appreciate everyone's iinput so far :) it been a good learning experience.

[dazed]

On a full tank I get between 39-42 mpg... All other times i get between 31-33 mpg.

I drive 50 miles everyday.... All motorway at 65-75 mph

I'm confused. How can the amount of fuel in your tank possibly affect your fuel economy to that degree?

Clearly the machine is lying to me lol :P

I just go by what the obc displays... I always reset the mpg display every time I fill up by holding the button for 1 sec...

What i will add from my observations is that I always manage 250 miles from 1/2 a tank...

I appreciate everyone's iinput so far :) it been a good learning experience.

The "Tank Average" display resets itself automatically when the car is refuelled.

Anyway, 250 miles from half a tank is good going - that's at least mid 30s.

[agent_dess]

The tank average is reset when you open the fuel fill door isn't it?

The Average fuel consumption and Average vehicle speed can be reset by holding the DISP button for more than 1 second while being on the relevant screen.

Refer to page 131 of the user manual.

I'm happy with what I get from the car the only thing that was annoying me was the information on display.. But hey I can live that :)

[Shepherd]

As far as I know its not the fuel fill door. It resets it if the fuel level sensor sees enough increase in fuel. For example, I have opened the fuel door to put in additive on half a tank and that did not reset the "tank avg mpg" counter. but adding 5 little of fuel was enough to reset it

[agent_dess]

Lol fair enough but the average man will usually only open the fuel cap to fill with petrol at which point the fuel sensor will be reset :p

But good to know :)