c220 cdi 2006 dpf poor fuel consumption

[Kinder]

Hi there,
couple week sago i got my MB, it got 92k on a clock, auto gerabox, and dpf installed.
have done just couple hundreds of miles so far but already realized very bad fuel consumption.
in town 25 mpg, motorway 37 mpg (with light foot), i had same figures with my old audiA4 auto/petrol

i done some search over yeasterday and what i found was:

thermostat could cause it, but - i takes ages to warm up (in town it takes up to 30 min), and it sticks to 80 C (sometimes it goes just above and then again comes back to 80). is it right working temp? all cars i had it was 90.

MAF sensor, but - if MAF sensor is dead it should be difficult to start engine, but now there is no problems with that at all.

DPF, but it would make 2-5 mpg difference, now i got 15-20 mpg.

any suggestions more than welcome.
thanks

 

[st4]

Did you instal a DPF on your car? If so, why?

Warm up sounds slow to be fair, it should sit at 90c too

 

[Kinder]

i really didnt istalled it
another thing that the universal Snap On - Solus pro scanner doesn't show any fault codes. maybe it need to be connected to STAR or something like that.
i don't really see a point got to delaer, cause i saw few lad's posts when MB dealers told them that high fuel consumption is ok. wt*?
where is point then to buy diesel car and have same mpg as a petrol? there is something wrong.

 

[Kinder]

had read in forums things like people getting some cardboard or similar stuff to block ventilation to radiator, so i just tried the same,
suddenly driving around town gave 35 mpg (from 24) motorway still around 40 (but around 1/3 of radiator still been uncovered, and faster speed on motorway gives more cooling)
so need to wait monday to get new thermostat, hopefully problem will be sorted

 

[Steve@Avantgarde]

Thermostats cause poor MPG as do worn injector nozzles. You should get at least 45mpg on a run if not more and around 35 round town.

MAFs rarely fail on 646 engines and even if it did fail, it would still start as its not the same as a hotfilm sensor on petrol variants, its a compression engine, so all it needs is decent fuel pressure.

Not all dealers have access to STAR, Indies do too and they are much cheaper than dealers and are far more likely to fix your car too. Snap on scanners often dont work or give spurious information on MBs, so seek an indie close to you with STAR who can help.