Hi all, I'm after some advice. Long story short, my 2014 Transit custom broke down and as a result needed a new alternator and battery fitted. Van is now fine, but I've noticed that my fuel range has been rapidly decreasing in comparison to before the alternator and battery replacement. I've heard that when the battery dies completely, it can reset such settings and the computer has to learn them again. I've driven over 100 miles in the van since the repair, and still no improvement with fuel range. A major concern for me was a few days back, I popped to the shops for 5 minutes. When I got back to the van and started the ignition I'd lost 10 miles of range. I've checked tyre pressures and no signs of anything else obviously wrong. I called Ford and they advised me to drive a while more and see if there's any improvement. If not, they would need to get it booked in. Any advice would be great!

It will take two or three tank fulls of fuel before the computer will have gained enough data for it to calculate your expected range. The van is not using anymore fuel than it did before the work was done, simply it just hasn't yet worked out a steady predicted range. Just be patient and it will sort itself out. 

In addition, the only true way to measure fuel consumption is to brim your tank full, then after driving getting some miles under your belt, then brim it again. Then calculate exactly how many liters your van has used to take you exactly how many miles. The onboard computer is just a sophisticated toy, but a toy nonetheless...