petrol reading after battery disconnect

[verachion]

Anybody know why my digital petrol display shows 170 miles after I disconnected and reconnected the battery? all the fuses are fine however, the correct reading should say 390 miles however it doesn't seem to be working.

[Crasher]

Pardon! A digital reading with no power? Am I misreading this?

[verachion]

Lol, sorry I wasn't clear in my last message,

I have power to the display however, instead of showing 390 miles left in the tank it came up with 170 miles and then after about half an hour driving it changes in multiples of 5 i.e 175,180,185 e.t.c e.tc.

Any ideas?

[Crasher]

Yes, that is the dash recalculating the range left in the tank (after losing power) from the minimum possible distance available with the amount of fuel reading from the gauge. It is a rough calculation and it takes a while for the range to be re-calculated based on your driving style.