disappointed with my 220CDI fuel consumption

[kinaero]

Have my E220CDI for 4 days now, done just over 200miles, average fuel consumption according to computer 34mpg!! all town work.

My ex C250CDI did 39.8mpg, similar journey, thought it would do better than my C250CDI if not at least the same fuel figures??

Apart from that both refinement and ride are miles better than the C class

 

[wemorgan]

There's always hope of 5-10% improvement as the number of miles increase.

My new car was delivered with tyres at too low pressure. Worth checking.

 

[Charles Morgan]

It is a little heavier, so you'll find urban driving more taxing on fuel economy.

 

[DSM10000]

As Charles said, you have a heavier car with a less powerful engine, this will have to be worked a little harder so an increase in consumption in town driving is not unexpected.

Assuming it is a new car then it is too early to really know how much fuel it will use until the engine loosens up and that can take several thousand miles.

 

[kinaero]

Ah! I got mixed up with the 250CDI engine!! According to Merc's own webiste the C250CDI does less mpg than E250CDI !!

Just double checking on the 220CDI engine, its the other way round, where the E220CDI does less MPG than C220CDI which makes sense as its a heavier car.

But why the E250 does better MPG than the C250 in urban figures??

 

[kinaero]

There's always hope of 5-10% improvement as the number of miles increase.

My new car was delivered with tyres at too low pressure. Worth checking.

Cheers, I'll check the pressure tomorrow.

 

[m1br]

It'll improve in 10k.
Mine is getting better, noticeably after about 6k.

 

[aquiss]

If this is a brand new E220CDI, then the published figures for Urban are between 51.4 and 49.6 based on the smallest wheel, which is 17"

The new E250CDI is reported to be 47.9

Results do improve in time, but I would have thought your figures were quite a bit off.


This naturally caught my eye as I am replacing my C250CDI for an E220CDI (literally 3 weeks from now). My C250CDi literally has stuck to 38MPG to 40MPG for urban for 3 years.....never got worse, never gets better. My old W203 used to do 48MPG for Urban with ease and hit 65MPG on M6 trips.....bring back to old days!

 

[V12]

Also, never trust the obc. Some can be out by as as much as 20%.

 

[aquiss]

It really does bring the question if these figures could be considered false advertising at point of sale?

If this was any other industry, the EU or even the UK's own, Advertising Standards Agency would be all over this, ensuring that figures were believable or factual.

Of course driving styles come into play, but the OBC should at least be correct, otherwise is this any different than changing the miles a car has done to make false claims?

 

[wemorgan]

It really does bring the question if these figures could be considered false advertising at point of sale?

Bar some cheating that was recently exposed, the figures are an accurate result of the standard EU test carried out.

IMHO it's more accurate to say that the test is not an accurate representation of real world driving. But I'm not sure OEM are to blame.

If this was any other industry, the EU or even the UK's own, Advertising Standards Agency would be all over this, ensuring that figures were believable or factual.

Most advertisements now state that the figures may not represent real world figures. As said above, I think it's the EU that's to blame, not OEM.

Of course driving styles come into play, but the OBC should at least be correct, otherwise is this any different than changing the miles a car has done to make false claims?

My SLK is accurate to ~1mpg. So I guess progress is being made to make the OBC better.

 

[kinaero]

well I just drove it downhill stretch(approx 2miles)

My current E220CDI(S212) managed only 33+mpg

But in my last C250CDI(S204) it would easily registered between 45-50mpg given simlilar traffic conditions(light)

 

[kinaero]

This naturally caught my eye as I am replacing my C250CDI for an E220CDI (literally 3 weeks from now). My C250CDi literally has stuck to 38MPG to 40MPG for urban for 3 years.....never got worse, never gets better. My old W203 used to do 48MPG for Urban with ease and hit 65MPG on M6 trips.....bring back to old days!

Looks like we are both doing the same then, my last car was a C250CDI, now E220CDI.

Done 14500 miles in C250CDI from new, 95% town work average 39.8mpg

 

[aquiss]

Looks like we are both doing the same then, my last car was a C250CDI, now E220CDI.

Done 14500 miles in C250CDI from new, 95% town work average 39.8mpg

My figures are almost the same....I've done 15200 miles, from new, in the C250CDI and my average is 39.7mpg (servicing made no improvements) for the same 95% urban driving.

I would say we are both very good examples of real world figures for C250CDI's

 

[wemorgan]

Isn't the book value for the urban cycle ~45mpg? In which case you're only 10% down.

 

[HumberMart]

One of the first things I do when I borrow a loan car (usually an E220/250) is check both the overall average mpg since reset, and the latest trip figure, usually the result of the MB staff's journey into work that morning.

Obviously based solely on the OBC, I'd say the range of readings (all cars are generally 3-6 month old with 4-8K), vary from 39 to 42 mpg from reset. This would be based on a sample of 6-7 cars over the last year, so I'd be hard pushed to tell any difference between 220/250's.

I did have a C250 coupe once, and this was noticeably more economical, easily topping an indicted 50 during the 2 days I had it, whereas the E's would usually return 44/45 in my hands of mixed driving.

In comparison, my ML350 indicates 29.8 over its 23K since new (mainly local journeys), and the B180 47.8 over 22K (longer journeys) before we swapped it for the (currently poorly) S350 that showed an average of 34.0 over its 46K by the previous owner.

 

[igk1]

It is odd how variable the consumption on these cars is. I'm on my second E220CDI with the OM651 engine, in urban driving I manage 40ish mpg, and on a long run keeping at a reasonable speed I have got nearly 60mpg. These are real figures - the OBC is optimistic by 5-10%. The earlier car had the 5g box and was not as economical but not bad.
My wife has a ML250 with the same 250 engine - that manages about 35mpg urban and 40-43 on a run - less than published but reasonable considering the size/weight/4Matic etc.
I've found it does improve with time but not dramatically. Some of the posts here show figures way better than I get, but quite a few people get a lot worse. It would be good if there was a definitive reason why this is - and whether there is anything like a software remap that can be applied to improve the poorer performing engines.

 

[kinaero]

Isn't the book value for the urban cycle ~45mpg? In which case you're only 10% down.

Yes Merc quoted 44.1mpg for C250CDI estate auto, so thats pretty much around10%

But Merc also quoted E220CDI estate auto the same at 44.1mpg urban, but mine so far average 34mpg, more like 10mpg down

I do expect improvement over time though.. lets see what happens after a few thousand miles

 

[kinaero]

Hang on a minute! Where did one of my posts gone to? And along with all the thanks I've given out earlier this morning?? Its disappeared!!

 

[HumberMart]

It is odd how variable the consumption on these cars is. I'm on my second E220CDI with the OM651 engine, in urban driving I manage 40ish mpg, and on a long run keeping at a reasonable speed I have got nearly 60mpg. These are real figures - the OBC is optimistic by 5-10%. The earlier car had the 5g box and was not as economical but not bad.
My wife has a ML250 with the same 250 engine - that manages about 35mpg urban and 40-43 on a run - less than published but reasonable considering the size/weight/4Matic etc.
I've found it does improve with time but not dramatically. Some of the posts here show figures way better than I get, but quite a few people get a lot worse. It would be good if there was a definitive reason why this is - and whether there is anything like a software remap that can be applied to improve the poorer performing engines.

There is a whole industry out there selling remaps to improve economy, especially in white van world.

We had our old B180 CVT remapped, and I know it improved the economy from about 41 to 44 mpg. Others will argue that improving economy by remapping is against the laws of physics/thermodynamics, but I'm chartered in these disciplines with years of experience so speak with some authority when I say that it does work. Some will argue it just fools the OBC so you think you are getting more mpg, and their is some truth in this feature, but brim to brim tests of course are accurate. This subject has been done to death on hundreds of forums/threads, so I don't suggest we start another one now (sorry for sowing the seed!)