clk w209 poor fuel economy

[ash1212002]

Official figures state 33mpg

My first fill up since purchasing the car clk 200 coupe automatic 57 plate, achieved 26.9 mpg total miles done since fill up 316.7 miles - light footed driving, very occasionally I would give it some welly

As its the revised m271 engine I would have expected a lot more miles

My partners c180 coupe 53 plate is achieving 400 miles with ease

Is this acceptable, could there be an underlying issue?

Was thinking of trying forte petrol saver and forte injector cleaner whether that would help and make a difference in the mpg

 

[geraldrobins]

Try swapping cars for a real comparison.

Your comparison isn't really very accurate and it seems the car is new to you. Is the 26.9 OBC or calculated?
Both autos?

 

[ash1212002]

Try swapping cars for a real comparison.

Your comparison isn't really very accurate and it seems the car is new to you. Is the 26.9 OBC or calculated?
Both autos?

partners car is a manual kompressor

my clk is 5 speed auto kompressor, the figures mentioned is OBC

 

[Ted]

They aren't the best in the world for economy.
http://www.mbclub.co.uk/forums/atta...ruly-astonishing-economy-image-2664843576.jpg

My old 208 with the m112 320 was better.

http://www.mbclub.co.uk/forums/atta...ermostat-fuel-consumption-image-562568935.jpg

 

[ash1212002]

This is what i achieved before i filled it up today

 

[ash1212002]

Going to give it 1 dose of forte injector cleaner, see if that makes any difference

 

[ash1212002]

They aren't the best in the world for economy.
http://www.mbclub.co.uk/forums/atta...ruly-astonishing-economy-image-2664843576.jpg

My old 208 with the m112 320 was better.

http://www.mbclub.co.uk/forums/atta...ermostat-fuel-consumption-image-562568935.jpg

Surprised the older engines perform better!

 

[Codger49]

You're driving too slowly!

Seriously, my W209 has poor mpg in towns and on bendy, hilly country roads. It only goes over 30 mpg on more open roads.

 

[ash1212002]

You're driving too slowly!

Seriously, my W209 has poor mpg in towns and on bendy, hilly country roads. It only goes over 30 mpg on more open roads.

Haha i have given it some welly now and again

Prefer to cruise along and put my foot down when necessary

 

[Codger49]

Yes, but 22mph average for 316 miles must indicate a fair few miles at low speed.

It may also be an auto issue, I find I need about 40 mph and a light touch on the throttle to get the auto box into top gear on my E46, and I guess the CLK may be the same; although to be honest my 7G box is so smooth now its had its software updated I can't tell what gear its in until it gets fast enough to match speed against revs.

 

[ash1212002]

Yes, but 22mph average for 316 miles must indicate a fair few miles at low speed.

It may also be an auto issue, I find I need about 40 mph and a light touch on the throttle to get the auto box into top gear on my E46, and I guess the CLK may be the same; although to be honest my 7G box is so smooth now its had its software updated I can't tell what gear its in until it gets fast enough to match speed against revs.

My trip to work one way is 12 miles of which approx 7 to 8 miles im on the dual carriageway doing approx 60, the 5 speed auto i think it gets into 5th at 50 to 60 i think, i do notice when the gears are changing up or down, feel a little judder

Is there anyway of determining if there is a new ecu or gearbox update available for my vehicle

 

[geraldrobins]

My trip to work one way is 12 miles of which approx 7 to 8 miles im on the dual carriageway doing approx 60, the 5 speed auto i think it gets into 5th at 50 to 60 i think, i do notice when the gears are changing up or down, feel a little judder

Is there anyway of determining if there is a new ecu or gearbox update available for my vehicle

I expect its only warmed up properly towards the end of your journey especially in winter.

 

[ash1212002]

I expect its only warmed up properly towards the end of your journey especially in winter.

I would say it takes approx 10 mins to temp, during this time i take it really easy with the throttle, well i try lol

 

[KillerHERTZ]

Your looking at the wrong screen, scroll across to the 'since start' instead of this, the 'since reset'

Its so low as your average speed is 22mph in over 14 hours.

The since start will give you an upto date reading.

 

[Codger49]

My trip to work one way is 12 miles of which approx 7 to 8 miles im on the dual carriageway doing approx 60, the 5 speed auto i think it gets into 5th at 50 to 60 i think, i do notice when the gears are changing up or down, feel a little judder

Is there anyway of determining if there is a new ecu or gearbox update available for my vehicle

A journey I often make is from my home to Ashford, its about 12 miles with the first half on bendy country roads, max 40 mph and the second half on a new 60 limited single carriageway with almost no junctions. I reach 29.5 mpg just at the end of the 60 limited road.

I know we have different engines, but the mechanical work required is going to be pretty similar, so I think your mpg is 'normal'. It would be mileage after the 12 miles where the mpg would improve.

Regarding your gearbox, I don't know about particular s/w updates, I guess you would need advice from an experienced MB technician.

Has your car had the gearbox fluid changed at 39-40k miles? MB have varied the 722.6 change interval mileage from 'never' to 'once at 39k' to 'every 40k'. I have seen on another forum that 2007 handbooks did not have any mention of a fluid change requirement.

Changing the transmission fluid and filter is always the first recommendation for all MB auto gearbox issues.

 

[ash1212002]

A journey I often make is from my home to Ashford, its about 12 miles with the first half on bendy country roads, max 40 mph and the second half on a new 60 limited single carriageway with almost no junctions. I reach 29.5 mpg just at the end of the 60 limited road.

I know we have different engines, but the mechanical work required is going to be pretty similar, so I think your mpg is 'normal'. It would be mileage after the 12 miles where the mpg would improve.

Regarding your gearbox, I don't know about particular s/w updates, I guess you would need advice from an experienced MB technician.

Has your car had the gearbox fluid changed at 39-40k miles? MB have varied the 722.6 change interval mileage from 'never' to 'once at 39k' to 'every 40k'. I have seen on another forum that 2007 handbooks did not have any mention of a fluid change requirement.

Changing the transmission fluid and filter is always the first recommendation for all MB auto gearbox issues.

Had a brief conversation with Andy Gayle who is based in Birmingham with regards to poor fuel consumption and whether I should replace the ATF and filter, and although it is recommended by MB Andy advised he wouldn't replace it there is no reason to even though its on Mb's service check sheet!

In relation to what I am achieving based on my trips he thinks potentially there is no issue and if I took it on a long run I should expect better mpg

 

[edtzxr]

Try resetting the auto gearbox. it learns your driving style but will have learnt a load of crap by now. seriously I saw nearly 50 more miles out of a tank when I did mine all be it mine is a 320 clk 1999

 

[ash1212002]

Try resetting the auto gearbox. it learns your driving style but will have learnt a load of crap by now. seriously I saw nearly 50 more miles out of a tank when I did mine all be it mine is a 320 clk 1999

What's the procedure to reset, does it need to be connected to the star or can I do this myself?

 

[MancMike]

You do a bit of a dance routine sat in the car. I can't remember exactly how it is and it'd be different for your car anyway. Search w209 autobox reset procedure and see where you go from that.

 

[ash1212002]

You do a bit of a dance routine sat in the car. I can't remember exactly how it is and it'd be different for your car anyway. Search w209 autobox reset procedure and see where you go from that.

cheers found this https://www.youtube.com/watch?v=BkNGe3q_dnM