Hi Guys

I need some help!

My wife has an SMAX 2.0tdi manual titanium MY2010, it has approx 80,000
miles on the clock.

The car had been great up until now and returning a very good fuel economy, we
took it into Ford a month ago to have a basic service, oil, oil filter, fuel
filter etc.

Since getting the car back, we have noticed that it now does about 100 miles
less on a full tank (10-15%), there have been no changes in driving styles,
habits, routes etc and the car seems to drive fine other than the fact that the
fuel economy has dropped a lot!

We have taken it back to Ford and they can't see any problems, any ideas as
to what might have happened.

Your help is much appreciated.

Thanks and regards

Hi Guys

I need some help!

My wife has an SMAX 2.0tdi manual titanium MY2010, it has approx 80,000
miles on the clock.

The car had been great up until now and returning a very good fuel economy, we
took it into Ford a month ago to have a basic service, oil, oil filter, fuel
filter etc.

Since getting the car back, we have noticed that it now does about 100 miles
less on a full tank (10-15%), there have been no changes in driving styles,
habits, routes etc and the car seems to drive fine other than the fact that the
fuel economy has dropped a lot!

We have taken it back to Ford and they can't see any problems, any ideas as
to what might have happened.

Your help is much appreciated.

Thanks and regards

If 100 miles equates to a 10% reduction in m.p.g. - that means you were getting 1000 miles from a full tank before the service ? ?

If 100 miles equates to a 10% reduction in m.p.g. - that means you were getting 1000 miles from a full tank before the service ? ?

Sorry! I didn't clarify this before, we live in Spain and it's kilometers here.

The car was giving approx 1100 km on a full tank and now it does approx 150 kilometers less!

dont surprise me,my missus had a brand new 60 plate tdci,and from day 1 the economy was dire.

even on a long run up to wales we couldnt get more then low 40's to the gallon.

even when we complained and they supposedly checked it out and then said there was nothing wrong with it.

my smax is a hell of a lot better then hers ever was.

Wrong oil perhaps?

Is it the garage you normally use?

If increased fuel consumption is not related to a change in driving habits then It could be due to servicing idsues. I would suggest you take a look at the air filter, if dirty change it. Maybe higher ambient temperatures are having an adverse affect.

If increased fuel consumption is not related to a change in driving habits then It could be due to servicing idsues. I would suggest you take a look at the air filter, if dirty change it. Maybe higher ambient temperatures are having an adverse affect.

That's the weird thing! The car went into a Ford dealer and had a service done, air filter, oil filter, fuel filter etc.

You would assume that things get better with new and clean parts rather than the other way! Could the quality of oil really affect fuel consumption? They say that the put in the recommended oil, whatever that is.

Thanks

I don't trust main dealers or any garage really. I've been charged for new air filters when it hadn't been changed. Best check yourself.

Don't think your oil will be an issue unless some moron has replaced it with a very very low viscosity type. I would have thought you should be using something like Castrol 5W-30 fully synthetic.

I'm only a diy mechanic so can't help with any more technical possibilities but as far as I know fuel consumption comes down to air intake issues, driving style, and the cars ECU control of the fuel mixture. As far as I know the ECU looks at your accelerator pedal position and the signal coming back from the MAF device mounted in the air intake and your exhaust lambda sensors signals, then based upon these it sets the amount of fuel being injected into the engine.

So if I'm correct you need to check your air filter, clean the MAF, check the lambda sensors. You could also have a word with the garage who serviced the car for additional ideas.

Hope this helps

Ambient temperature also effects the mpg, are you using the air con more, heater more, letting the car warm up before starting your journey? They will all effect mpg. Also, as the price of fuel is dropping I wouldn't put it past the 'big fuel companies' to reduce the amount of niceties they add to the fuel so their production cost is reduced! (I mention the fuel companies because just before I sold my mk6 fiesta I changed the timing belt and changed both lambda sensors. I was getting 48 mpg which suddenly dropped to 38mpg as the temperature and fuel price dropped! Coincidence? Draw your own conclusions)