Fuel consumption ML550 2012: 30% higher than MB-specified?
 

I'm driving my ML550 2012 (new from MB dealership) since Nov'12, ~4,200 km so far; the carhttp://images.intellitxt.com/ast/adTypes/lb_icon1.png gauge shows 18 l/100km average actual consumption, while the MB tech specification for the model is 12.5 l /100 km - combined.
Can it be something technically wrong with my truckhttp://images.intellitxt.com/ast/adTypes/icon1.png?
My driving style is quite reasonable, hardly ever more than 2500 by tachometer. I'm in Southern Ontario, Canada, the winter is mild, I keep the truck is garage & I don't idle.. I've just measured my last 100 km of my day-to-day city drive (no traffic congestion/reasonable pace/no a-conditioner or heating) - it's 19.2 l / 100km!
So if that's correct & it is the actual consumption of the truck is 6+ lit/100 km more than MB official fuelhttp://images.intellitxt.com/ast/adTypes/lb_icon1.png economy data, can it be a sufficient reason to return the truck to MB & get money back, or at least claim a replacement for a different model (e.g. BlueTech) - ?
I understand that manufacturers give their figures with the ideal conditions, thou e.g. for our Honda Odyssey it's posted 10.9 l / 100 km - & we get 11.9 l average with our predominantely-city drive.
Why should MB differ by more than 30% with what they post & what the truck's gauges actually show?
I just wonder if other owners noticed it similar?

Um basically no. You are entitled to nothing. I would say maybe don't buy a V8 if you want high fuel mileage.

I'm not the one of "entitled generation" Hutch, rather "old school".. It's not about high milage per se, but rather MB's responsibility for the info they publish..
So what does your gauge tell you on average & how does it compare to MB's figures?

rayevskiy_a that does seem way too high.

Mine has just ticked over 10,000kms. It's a Nov '12 build. I've also got Airmatic, ON & OFF road pack, and Active Curve System.

I haven't reset any of the trip computers since delivery back in January. It's showing 14.9l/100km as my average usage since then.

I have had it down as low as 10.5l/100km on a long highway drive between Melbourne & Sydney, which is almost 900kms. I think that's excellent for the size and weight of this vehicle.

I live approx. 20kms from Melbourne's CBD. When I leave home I have about 5km of suburban driving at 40-60km/h then around 15km on the freeway at 80-100km/h to get into Melbourne. Initially the fuel consumption under 'from start' shows 20l/100km but by the time I've arrived in town it usually shows around 13.5-14l/100km, so your commute at 19.2l/100km is way too high in my opinion.

Either you're driving it very hard, but you said you weren't, or there's something seriously wrong. I'd be talking to your dealer soon.

Are your tyre pressures correct? I have mine at 32-33psi. I am also using Premium 95 or 98 octane fuel only.

Happy motoring .... :zoom:

Your foot might just be heavy.

Thanks Aussie, I've written to the dealer - they are just trying to brush it off: how much a tire pressure would matter? Extra 5% - ? (by the way, the tech spec advises 45 psi - front & 48 - rear) - As I say, it's 30% difference on this truck so far

45/48 psi woud be a gut buster... yes, if your mileage measure does not hit 50% at highway continous speed - which is governmental test not MB - then yes, you will not come close to the combined published "mixed" mpg target..

Same vehicle, also in southern Ontario. Getting 15 l/100 km over 12,000 km of mixed driving. Little highway use, mostly suburban commuting and average speed per tank is around 45 km/hr. I recommend you start tracking actual fuel economy via fuelly or one of the other online sites. I am not dissatisfied with my fuel economy, its what I expected for a heavy V8 SUV and I would buy the same engine again as I love the power.

What is your average speed?

Thanks MLBlue, that's the kind of of info I've been asking: it has nothing to do with V-8 or power vs economy, I am just trying to find out why my actual economy is so different from the MB posted figures. German engineering/calculations should be more prescise than Honda's - that's one of main reasons we are paying the top buck for their cars, and as I said above, that doesn't seem to be in my case.
My average speed is ~32km/h over the last 110 km (vs your 45), & the gauge suggests 19.2 l / 100 km (vs your 15)

I would say we are on par. If you got that average speed up to 50+ your mileage would really improve. Try resetting it at every fuel up and recording it on Fuelly. I just moved to a new office last month which is going to be a smoother highway drive and I am already seeing an improvement as my average speed is increasing. Check out my profile on Fuelly.

Sometimes cheap gas will be a factor as well

Worked hard on today's commute to get a better number and averaged 11.1 l/100 km and 60 k/hr over the 40 km round trip. Far less stop and go on the new commute = much better numbers.

A couple thoughts and comments:
- Fuel economy in winter is always worse than summer. Your results are November to May, the worst period for fuel economy and much colder temps than what the EPA testing cycle takes into account.
- Are you buying gas with ethanol? I noticed a slight difference running Shell (no ethanol) vs Esso (up to 10% ethanol).
- Are you using 91+ octane always?

In any case, great truck - enjoy the torque :)

Thank you YYZ, the torque is great;
it's specified not less than 91 octane: not sure if anyone tries to use a cheaper one on a brand-new 100$K truck :)
few places offer 95 oct - and I didn't see the point to search for such places/pay for higher octane - may be I should try on some occasions & compare it with the 91-economy
I didn't pay attention if ethanol is there, usually used Esso or Lawblaw's
For the tires pressure, the driver's door sticker suggests 45 - 48 psi, thou the fuel cap door posts it 35 psi - which is the correct one from MB-tecnician's perspective (& they don't know why the driver's sticker sugests it that high)

You'd be surprised by the number of threads where people claim 87 octane is fine for a Benz - go figure :)

Esso has up to 10% Ethanol if I remember correctly. Can't speak to Loblaw's, but why buy gas at a grocery store?! They generally have a sticker on the pump to indicate Ethanol content (if any).

35 is the correct PSI, the 45/48 is maximum (used during transit). I used to run 37 in my ML550 and currently run 37 in the ML350 as a matter of preference, though I have the 21" wheels.

Cheers.

With 93 Octane and 0% Ethanol gas, I get 18.7 mpg on the freeway going average 75.