[Simon G]

I hope there’s someone out there that can shed some light on a really strange change in the range until empty indication on my fifteen year old 2.0ltr crdi. To shed some light on the sequence of events that have lead up to current situation.
I had to replace the alternator a couple of weeks ago, which I had done at a local garage, at that point I was getting approx 530 miles from a full tank, however last week I decided to fit a new battery after a check recommended replacing it. Fast forward to yesterday when I filled up with 8.5 gallons and at that point the indicated range until empty plummeted to just 370 miles. Given that the dash readout for mpg is 59 I can’t work out what’s going on.
If anyone out there has experience of this or knows what the problem is I’d be infinitely grateful if you could shed some light on my issue.
Cheers
Si

[eye30]

Only a thought but as you changed the battery I'm wondering whether the on board computer has by chance reset to zero/factory and will have to relearn your driving style.

[Simon G]

Hi eye30, I know what you say about the computer resetting itself, but I’d have thought that with a near full tank of diesel it would show a lot more mileage than the 370 or so🤷🏻‍♂️

[eye30]

Just as an example a few months ago I filled to the brim with petrol for a trip of some 320 miles.
Think to empty showing 380 so enough without topping up.

I think it was showing average consumption of 35 mpg.
During trip up M6/M8 and few A roads it went up to 48 mpg.

At destination I had just over quarter tank and to empty 120 miles.

So this was to empty 440 from fill up.

So appears I gained 60 miles.