VXOC Astra-J/GTC

Full Version: Astra J 1.6 CDTi increased fuel consumption
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A few months ago my car started consuming around half a liter more of diesel on a regular basis. I thought maybe it was the winter weather, but the winter was very mild here in the end. Now the temperature is usually pretty high, as we are approaching spring, so I'm having a hard time finding temperature the problem.

I waited to see how the car will behave after doing a yearly service - oil change, new oil filter, fuel filter, air filter and also changed the timing chain oil tensioner because of the rattling chain. This yearly service was done about 15000 km (9300 miles) after the first one I did after buying this car.
Now, two weeks later I can say that nothing has changed - the average consumption is 6.2 l/100 km (per the BC, while the exact value would be around 6.5 l/100 km). Before this "issue" the consumption was on average 5.7 according to BC and 6.0 was the true calculated value.

My usual driving schedule is a week or two of city driving and then a round trip of 300 km (190 miles).
The round trip is where I'm noticing the most significant changes. When driving around 130 km/h (80 mph) on the motorway the consumption shown on the BC is usually 6.5 l/100 km, while before it was 5.5 l/100 km. And when driving 100 km/h (60 mph) I get around 4-4.3 l/100 km, while before it was 3-3.5 l/100 km.
So basically what happens is that I fill up the tank, reset the BC, drive one leg of the road trip and my average consumption is more than 6 l/100 km, while before at times it would be less than 5 l/100 km in this use case.

99% of the time I'm driving alone in the car and it has 185000 km (115000 miles) on the clock. It's a 110 hp model.


Sorry if I bored you with too much information, I just wanted to be thorough.
tl;dr would be - the car is consuming 0.5-1l more of diesel fuel than expected, yearly service done, chain rattling fixed, no errors read with diagnostics.


Does anyone have an idea what could be bothering me and the things that should be checked first?
a few things to check fuel pressure sensor, EGR etc been cleaned?
Nothing cleaned yet. I was thinking of getting a cleaning arranged but wanted to get some input first on possible causes.