How does the MPG computer work...

Renaults dodgy electrics,

i tend to find if you bin on a long drive and you get 30mpg out of it and then you go fill up, then rag the granny out of it for an hour of two it it might only read 24 mpg, but if you reset it at the garage then go and *** it it will sit around 16 mpg cos its taking an instant mpg reading and not an average .

if you fill up then rag and you not reset it for around 100 miles then i think it works it self out on an average not an instant reading.

i personally re set it every time i fill up but 9 times out of 10 i ignor it any way, the computer dose not dictate to me how much fuel im using my right foot does ( IMO )

Well thats how i take it to be but if you never reset it can it then give you a true reading on what your using ...

er no it cant, but if you reset it every time it gives you a good idea.

i normally go by wat the miles left reading tells me

My brother has just got an Astra Sport Hatch 1.8 SRI and he says that he is not ever going to reset his computer so that it can give him a true account as to his MPG and the more info it recieves the more it will know what his driving is like ..

my mates new vectra is the same, its always on the move in mpg, gives you a perfect read out, our after a while just sit at one no and not really move till you reset it.

But that is instant MPG so it will act a bit like vac gauge when you put your foot down it goes right down and when not it read 999 miles/ gal ...
The point i am trying to prove is how the computer works does it remember what you used on your last tank of fuel and re calculte accordingly when you re fill ...

I think the mpg readount on the meg is related to the distance on your trip computer

Topper225 said:

But that is instant MPG so it will act a bit like vac gauge when you put your foot down it goes right down and when not it read 999 miles/ gal ...
The point i am trying to prove is how the computer works does it remember what you used on your last tank of fuel and re calculte accordingly when you re fill ...

Click to expand...

no i dont think it does, good question tho

So should i reset eveytime i fill up or should i leave it to allow the computer to gather more info on my driving and fuel consumption ....

reset it every time IMO

I always reset mine when i refuel. Perhaps webcode could give us a detailed description of how it works :lol:

Yes that would be helpful . Webcode ???

The MPG is related to miles driven. So if you reset after filling up then drive 100 miles at 6000rpm your mpg will be lower than if you drove 100 miles at 1000rpm. If you never reset it it will take ages for your driving style to affect the reading in mpg, if it shoes 25mpg and 500 miles you will have to potter around for ages to get the mpg to go up.
Hope that makes sense?

Yeah it works on miles done and then calculates the fuel used to get the average.

So if you just fill up and boot it your gonna have less mileage and so poor enconomy, i get where you are coming from sure if you never reset it you will get a kind of overall average.

I would however reset it each time you fill up as the range and trip are calculated from this.

My old toyota used to have average and instant consumtion which gave you an idea how much gas you are guzzling at any given time.

Only a bit poor on the renault is the range wipes to -- when less than 50 iles are remaining. but i guess prett handy and pretty acurate.