MB Fuel Consumption

Smacsor

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Old chestnut I know but I have posted previously about MB being particularly bad regarding claimed vs actual fuel consumption compared to other marques.

Call me cynical but I wonder if the OBC figures are deliberately skewed excessively in the hope that customers will be fooled into thinking their vehicles are better than they are? The reason I say this is that my OBC has been 8.8% optimistic over the past 4000 miles.

Compare that with my VW where the OBC has UNDERestimated by 0.1% and you can see why I'm cynical.

Or is my OBC just particularly bad?

Simon
 

Argus

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My OBC reading is about 15% out. Over 20k miles the reading is 40mpg but the actual calculated figure is 34mpg.
Quite useless really.
 

st4

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Mines within 5%. So I've averaged 42.5mpg but only really 40mpg.

Goes well for a 2.1 litre. Had a brisk drive back from Kilwinning last night, and you know the sort of travel where there is brisk A road and motorway driving, the way the car can slow to take a roundabout at 30mph and be back at 70 so very quickly without really having to spank it.

That matters more than £1 per week
 

roop_the_loop

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Old chestnut I know but I have posted previously about MB being particularly bad regarding claimed vs actual fuel consumption compared to other marques.

Call me cynical but I wonder if the OBC figures are deliberately skewed excessively in the hope that customers will be fooled into thinking their vehicles are better than they are? The reason I say this is that my OBC has been 8.8% optimistic over the past 4000 miles.

Compare that with my VW where the OBC has UNDERestimated by 0.1% and you can see why I'm cynical.

Or is my OBC just particularly bad?

Simon

And there I was foolishly thinking that the OBC figure is accurate, as opposed to the official gov't fairytales!

So what you're saying is that when my official figure is 53.3 (combined), and my OBC shows 42.2, what I thought was already an unacceptably large gap is actually even worse?

(Great.)

As to your point about MB being worse than others, I did see an article earlier this year saying that the gap between official and actual mpg has been growing wider in the past ten years or whatever, but if I'm not mistaken it did also say that MB was one of the biggest bull$hitters in this respect. Wish I'd saved that article, I can't remember how the different makes compared otherwise.
 
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Smacsor

Smacsor

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Mines within 5%. So I've averaged 42.5mpg but only really 40mpg.

Goes well for a 2.1 litre. Had a brisk drive back from Kilwinning last night, and you know the sort of travel where there is brisk A road and motorway driving, the way the car can slow to take a roundabout at 30mph and be back at 70 so very quickly without really having to spank it.

That matters more than £1 per week

I agree with that Steve. Would just be nice if the OBC was reasonably accurate like a VW rather than just for entertainment value!
 

roop_the_loop

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BTW, how does the OBC arrive at the mpg; where does it take the fuel consumption from? In other words, is the inaccuracy a technical problem (not being able to measure the consumption correctly - which I find hard to believe) or a 'political' one (deliberately showing the figure wrong to make it look better than it is)?
 

wemorgan

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O
Or is my OBC just particularly bad?

Anecdotally I'm reading that the OBD on modern MB is very accurate. On my R172 it's accurate to within 1 mpg.
 

survey

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On my 2008 C Class 220cdi Estate the brim/brim actual average mpg over 40K miles was 42.71mpg and the OBC averaged 5-6% over optimistic. On my 2012 E Class 250cdi Coupe the true average over 14K miles is 48.34mpg with the OBC is averaging 2-2.5% over optimistic. So maybe things are improving. Same style of driving.
 

MBDevotee

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On my ML (5.0 v8 2002) the OBC reads about 22mpg average, and i get about 18-19 in reality.

On the CLK 270CDi it reads about 49mpg but I am only getting about 39.


The OBC LIES!

I think it's because more people would be taking their cars back and whinging....

They boast about these mega economy cars, but in the real world they aren't all that good.
 

geraldrobins

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On my humble merc the obc is 4%-5% optimistic. On my previous passat the obc was 10% optimistic and about 2% optimistic on my previous bora. So I dont think mercedes are different to other manufacturers in this respect.
Regarding official figures again I think these can only be used as comparisons as everyone drives differently and does differing amount of motorway, urban and rural driving. But on the type of journey and driving style I regularly do I generally attain the official combined mpg when the ambient temperatures are over 15 deg C.
 

Devonian

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On mySL350 over about 20 fill ups the OBC has never been more than 1 mpg out, usually only 0.5 variance
 
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