I'm facing a problem with fuel consumption.
Putting it strait I have a much bigger fuel consumption at the pump compared to the one in the dashboard.
This happens for a few years 3-4 at least.
My car is a Mk II C5 2007 estate 2.0 hdi 100 kw 6 speed auto gearbox.
The last figures I had are these:
- 640 km with 59 liters of diesel; that is 9.2 l/100km (30.7 mpg) at the pump; the trip computer shows 7.8% (36.2 mpg). The drives I did tend to be closer to the trip computer figure than the pump figure.
- an older figure I remember was 850 km with 65 liters of diesel; that is 7.6% (37.1 mpg) at the pump compared to a 6.4% (44.1 mpg) on the trip computer.
When I bought the car I remember that I made 1100 km on a full tank of 65 liters with aircon active 30% of the distance. That was 5.9 l/100 km (47.8 mpg) which was very close to 5.6% (50.6 mpg) reported on the trip computer and the car's brochure (10/7.2/5.6 ext/mix/urb liters/100km) (28.2/39.2/50.6 mpg).
Since then I'm getting worse figures every fuel tank.
The car is in good conditions and I drive it very smooth. I don't do much city driving just shopping and visits. I rarely move the car in workdays. In the weekends is where I use the car the most and mostly for medium to long trips.
Now the car has 155k km and I bought it at 97k km.
The service intervals are in 10-12k km intervals, which is about once a year. The oil I use is Total ineo ECS 5w30.
At 118k km the car had a gearbox fluid refresh with Castrol jws 3309 oil.
I had the EGR replaced and DPF cleaned more than half a year ago and didn't changed anything in the MPG figures in a good way. By contrary, the difference seems to increase between pump and trip computer.
I know that I have 1-2-3 bad glow plugs because of bad starts in the winter under -10 Celsius but I don't think this issue has such big impact on MPG.
Any ideas are apreciated.