So my car displays the number of kilometers i have to go with the fuel i have left in the fuel tank at any one point.
I however noticed something strange, i have the habit of visiting the filling station only when the light shows, so on a full tank it would show 700km to go, by the time the trip shows 350-400km, the fuel gauge shows half, which makes sense, however the remaining half rarely does 200km, meaning i spend more when i have less fuel in the fuel tank which beats the logic since i had assumed that if you are carrying luggage in this case about 70 litres of fuel, the car is heavier hence should spend more and not the other way round.
Could someone explain why this is so.

N/B: This conclusion was arrived at since i use this car Monday to Friday to and from work, same route and same time with little or no stop overs or detours

Another factor may be the accuracy of the measuring instrument.

methinks this thread is misplaced... inafaa kuwa huko Technical /Review

Iko makanika wa grogoni ngara na kadharika

NA hii gadget,did it came with your car ama you installed locally?

Have also noted the same with my car.. The first half tank does about 350-450kms, the second half of the tank does 200-250kms at most.. Same driving style, same driver, same routes..

The shape of fuel tank - surely the manufacturers should consider that when placing the sensors for the fuel gauge.

Why do people think that the fuel gauge is not correct? It shows full when its full, and lights up at exactly same point every time..

Simple:
1. When you fill your tank, note it takes almost 80-100kms before the gauge moves from above full to the F position. Sasa start computing from there. By the time it hits E and lights up, depending on the car, you should have atleast 5 litres in there.
2. Fuel gauges are not designed for extreme precision. They could be but car manufactures do not see the benefit and is not worth the effort.
3. Just take note of your car's consumption and estimate mileage. Once you top up. Reset the trip meter and now the least kms you can get depending on whether it is city or highway driving. Use fuel gauge as confirmation/backup.
4. If you want more accuracy, if your car has a trip computer this data is available. Since gari zetu ni wasi wasi, I mostly rely on my understanding of the car.

The tank is shaped that way for structural and engineering reasons.
The scavenging system works with that design,the pump sucks fuel at the lowest point of the tank to ensure you run on "reserve" fuel in times of emergency.

Its not a gadget, car displays how much fuel you have both on the fuel gauge and also in terms of kilometers, you press this button that changes the views to show other stuff like how many kilometers to a liter, for a given trip, it can show, how long in hrs and minutes, fuel consumption average, speed average etc ,besides the normal views on the speedometer.

Highly doubt the shape of the tank would matter since am looking at the number of kilometers the car says the fuel should take me not the pin position.
Full tank=700km, when i measure the number of kilometers at half tank, its abt 350-400km and the cars says so, however even when the car says i have 350km worth of fuel it will only take me for 200km.
So i used to fuel 3 times in a month full tank always, so when i realized this, i started refilling the tank at every half tank, which was equal to 4 refills of half a tank each, saving a full tank worth of fuel in the process. This is what did not make sense. And maybe what harrydre said would explain it..

Maybe the 2000cc "new" car is more fuel efficient than the 1500cc..like its a VVTi-GDI-with chain timing belt!