hello all
not a problem but a general question ...

Does anyone know over what period and/or mileage is the "Average Fuel Consumption" calculated?

My XK8 is getting around 19.8 mpg around town and 22-ish with mixed freeway and city driving and seems to take forever to change

 

I believe it is calculated from the last time the trip odometer has been reset.

 

K westra's answer is correct as far as I can see. And the longer one waits before resetting the computer means one gets closer to the long term fuel consumption the car will deliver. However, it is possible to use the A setting for long term and the B setting for checking shorter runs.

 

And...unfortunately...once the battery is disconnected, both A and B revert to zero as neither is stored in non-volatile memory.

 

thanks guys.

Any idea over what distance/time the instantaneous consumption is derived?
I assume this is more to do with how much fuel the injectors are measuring at "this point" with some averaging factor over x miles/y minutes?