My octy 110tdi is struggling to return 50mpg some days and other days will happily achieve the mid to high 50's for the same (30 mile motorway) run.

The driving style is the same and I wouldn't say that the difference is due to driving style or weater conditions. Doing 70 will see the MPG pinned right down at the low 50's.

Anybody got any suggestions as to what to look at?

So far I have tried:

- New Air filter (made an improvement but this is gone after 2k miles)

- Cleaned MAF (made a slight improvement but again this has gone)

- Run Shell Derv extra which has had no noticeable effect

is it a pd or a ordinary diesel??

is it a pd or a ordinary diesel??

110 is non-PD

Could this change in economy simply be down to winter grade diesel now finding it's way into the pumps or has this been a problem for sometime.

i would check that the injection pump timing is ok and also it might be worth putting some diesel injector cleaner through the system.

also as eddyH has stated, the derv varies, and it may be because they are now switching over to use a winter/cold weather mix

I had considered all that, but tbh i have noticed it getting worse over a month maybe and get through a tank a week without any problem.

I have used millers diesel clean and put some 10k boost (derv edition) through to clean it all out. Does anyone know what values the MAF should be returning as trying the disconnect it method ended up with the car driving like there was no turbo at all.

autodata says you should be reading around 2.4 volts

Time to get the mulimeter out either that or get a vag com log.

Mine (not that it should be used as a benchmark!) Seems to return about 58-59mpg on my normal run home in the evenings from work (leaving about 6.30, arrivinmg home at about 8.00pm) on cr@ppy roads between Salisbury and Weymouth.

Keep you eyes out for a silver Octy II 2.0 TDI

Have you got a new MAF on yours matt?

I swapped it over about 18 months ago, and cleaned it a few months back to see if it helped with my turbo issues. But no suck luck (when I cleaned it!)

If my MAF was being odd wouldn't that result in not enough fuel being injected rather than too much?

No idea as such, but my mpg figures have taken a general hit over the last few weeks, and I'd love to see 50mpg with the climate control running just now!

Thats interesting as you have a TDI 110 too.

What sort of driving are you doing Ken?

Check your box mate. My route and times of travel don't very much, so I'm suspecting a combination of how the temperature's dropped markedly over the last 2 or 3 weeks, and winter fuel.

I thought it was just me :confused:

I have noticed an increase in my consumption lately, without being able to work out why, as my driving style hasn't changed, nor has my daily commute of 24 miles, part rural part urban roads. I know that when I'm able to press on at around 70 mph (on the rural part of the journey of course ) that does make a difference, but I used to get 60+ mpg, and now I'm getting 51-52. I do tend to get my fuel from Tesco, and know that it's not quite as good as say Shell.

HH

Shell Derv and Derv Extra are no better on the fuel economy.

Think i will hold off and wait before buying a new MAF until the next pay cheque then and see what happens.

It will be interesting to see if this continues and if not who gets improved economy back when.

I thought you bought a new MAF not very long ago? How about taking it back to the dealer adn telling them it is broken? Or find a nice person who lives locally who does not mind swapping MAFs for a day or two....

Nope i cleaned the MAF, not put a new one in yet.