Hi

I have recently started using the premium diesel fuels in our PFL 2009 estate and seen an increase in mpg.

In France I filled up twice on Supermarket diesel and then about 3/4 of a tank of premium to top us up.

After about 100 miles after being on around 75% premium diesel and even allowing for the motorway way, the fuel consumption increased. Now we are back home the consumption is still around 5mpg worse than it usually is. (I know the Trip Computer is optimistic but the numbers it has displayed are worse).

I have checked the tyre pressures and they are OK.

Could this be something to do with the poorer grade fuel ?

The engine sounds it's usual agricultural self.

Thanks

Matt

Brakes dragging?

hammering the aircon?

Take the duty free out of the boot!

MAF sensor?

Unplug it and see if it runs better.

Air filter?

Fuel filter?

Hello

Not really using the air con anymore than we did previously and sadly no duty free...

She does not sound as if the brakes are rubbing but I will try the sensor. I was wondering if we'd knackered the fuel filter with the second lot of supermarket diesel.

Thanks

Matt

For the sake of a couple of quid and 5 mins work, you could try changing the fuel filter and see if it helps

Changing the fuel filter would have no effect on MPG.

Perhaps the better mpg gained from premium diesel has temporarily foxed the car's brain and it will have to relearn what it can get from supermarket bilge.

Just an idea, if the MPG calculations aren't fixed but are based on actual performance.

If your fuel filter is clogged, you'd be getting better mpg, not worse.  Bear in mind that once the motor is up to operating temperature cool damp air will get you better mpg than warm dry air and could account for a 5mpg difference. Was it cooler where you were?

Hi

Good point on the temp. It was much hotter on Thursday when we drove back to England and the next few days here.

I will see why it does next weekend. There is no point checking the average milage now as my wife less frugally than me.

I might change the fuel filter anyway.

Thanks

Matt

Over the last 25 years or so, I have always found I get slightly better fuel consumption running on continental Diesel than the stuff over here. Less foaming too, although the UK seems to have discovered anti foaming additives too now. The higher %age of Diesels in France and Germany, and their lack of tolerance to being put upon would likely preclude rubbish fuel from there.

Could be the extra weight, or longer distance on empty autoroutes drawing you into higher speeds, dragging brakes, tyre pressures and or alignment. Lots of miles on the Pave'?

The air filter will likely make more difference than the fuel filter.

Quick update: Things are back to normal. I am going with fuel quality at the moment although as it is due for a service soon I'll ask them to look at the state of the air filter just as apoint of interest.

 

We loaded up again for a week in the New Forest but stayed at her usual MPG so I am a bit baffled really.

 

Anyway, thanks

I had the same myself. 61+ mpg in europe, 52-54mpg when back home. 2 tanks later back up to around 58-59mpg.