Mercedes Benz trip/MPG computer
Mercedes Benz trip/MPG computer
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Discussion

greenarrow

Original Poster:

4,508 posts

141 months

Friday 8th July 2016
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Anyone got any experiences of how accurate the MPG/Trip computer is on Mercs, particularly the older ones. I only ask because I am sure mine is pessimistic, which is the opposite to every other car I have owned which over-estimates the MPG figure

I put in £25 or £30 each time in my CLK430 (c208) and let the needle fall to the same point before refuelling. Doing this, I am getting at least 26 MPG per top up, yet my trip computer says the car is averaging just under 25 MPG....

Talking of which, 26 MPG aint bad for a V8. I also have a Mk2 Mazda MX-5 1.8, which I never average more than 32 MPG in, admittedly I do rev it a bit harder, but its a far smaller, lighter car and just a 6 MPG difference is quite surprising.

ZX10R NIN

30,095 posts

149 months

Friday 8th July 2016
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The easy way to work it out is to divide the cost of a gallon of fuel by the miles you've travelled so reset your trip meter & see. If you fuel is 112.9 a litre like it is here then it's £5.12 a gallon.

greenarrow

Original Poster:

4,508 posts

141 months

Friday 8th July 2016
quotequote all
ZX10R NIN said:
The easy way to work it out is to divide the cost of a gallon of fuel by the miles you've travelled so reset your trip meter & see. If you fuel is 112.9 a litre like it is here then it's £5.12 a gallon.
Yeah, that's what I have been doing....example, the last £25 gave me 129 miles, price was £1.109 per litre £5.04 per gallon) = 26.0 MPG. Previous £20 was even better, at nearer 27 MPG, which is better than the readings I see on my trip meter...

Like I say, surprisingly frugal for an old school big engine car.

ZX10R NIN

30,095 posts

149 months

Friday 8th July 2016
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Can't argue with the facts your OBD seems to be spot on, mines about 2mpg over.

mickyveloce

1,035 posts

260 months

Friday 8th July 2016
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My SL has the quaint, but rather meaningless, vacuum mpg gauge. As the car travels briskly on a light throttle application, it does 30mpg a lot. Probably.

Isn't it odd though; our barges irrespective of engine size, weight and age all seem to be hovering around the 26-30mpg bracket. Contemporary road tests on modern hybrid and blue/ green/ Eco stuff all seems to return 40ish, despite outlandish government figures.

Stick with the old stuff I say.

niva441

2,097 posts

255 months

Tuesday 12th July 2016
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My W203 generation C class (2006) was always about 1 or 2 mpg pessimitic on fuel comsumption. The current W204 generation is about 1 0r 2 mpg optimistic.

s70rmp

676 posts

153 months

Tuesday 12th July 2016
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I'm happy when I see 50mpg + in my 3ltr V6 diesel, it's better then I expected. Did see 74.4mpg once in my 2011 C220 Coupe travelling across France the other year.

dkatwa

577 posts

269 months

Tuesday 12th July 2016
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Currently averaging 26.6mpg per OBC (80% cruising at 60mph on the motorway) in my CL500/ 2002

Actual mpg, when filling up brim to brim, is around 26-27 mpg so the computer is spot on


MaxNg

205 posts

223 months

Wednesday 13th July 2016
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I have a 63-plate E220.

I reckon the computer is pretty accurate, even a little pessimistic, when comparing the computer with an IPhone app, which keeps track of fuel used. For the last refuel, the computer gave 45.6 and the actual was 46.9.

The best was on a run from Scotland to N Wales, where both actual consumption and the computer were 52mpg.


daveenty

2,382 posts

234 months

Thursday 14th July 2016
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My on board thing tells me that I've averaged 22.8mpg over the last 4,700 miles whereas fuelly.com tells me 22.9, so not a great deal of difference really. I used to have the "Trip Menu From Start" displayed all the time, but found that this was affecting my driving, in that I was constantly striving for more from it, so now have either speed or navigation instead and just check upon arrival. Or not. smile

It's mostly used for motorway stuff like getting to a venue, then ragging it about for a couple of hours and motorway again going home.

Sandgrounder

564 posts

168 months

Friday 15th July 2016
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I've got a 2012 E250 cdi. JUst filled the tank last night and did some maths. Computer says 43.5 mpg over 560 miles. The fuel I put in divided by this mileage equates to 42 .1 mpg, so I think that is close enough for me.

gizlaroc

17,251 posts

248 months

Monday 18th July 2016
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My E350cdi used to show 33.6mpg, no matter how many times I reset it that is where it would end up again after a few tanks. The actual MPG was 32mpg calculated.

My E350 cgi shows 28mpg, no matter how many times I reset it that is where it would end up again after a few tanks. The actual MPG is 29.5mpg calculated.

I think that if you do lots of short journeys (sub 10 miles) it throws the OBC out more.

I also have a c320cdi sport estate as well as the E350cgi sport estate, the diesel starts at 40mpg and slowly goes down from a cold start, where as the petrol E starts at 14.1mpg and slowly climbs.

What I have noticed if I do a whole tankful doing nothing more than school runs (6 miles) and back and forth into the city (10 miles) that both of them are more out than if I do my London runs (100 miles).
The diesel optimistic and the petrol pessimistic. The more longer runs I do on each tank the more accurate it gets.

greenarrow

Original Poster:

4,508 posts

141 months

Tuesday 19th July 2016
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My car is now with its new owner, but once I started doing manual calculations I never got below 25 or 26 MPG and the best was just over 28. The trip computer never wavered moved from its average 24.7 across 1300 miles in all the time I had it.

Interesting too that people like me with the old school V8s weren't getting an awful lot less than others with the more modern Merc petrol engines... I guess that's another subject entirely!!

V10 SPM

606 posts

275 months

Tuesday 19th July 2016
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I have averaged 15.0 over 6000 miles according to my trip computer and unfortunately it is pretty accurate!

ZX10R NIN

30,095 posts

149 months

Tuesday 19th July 2016
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greenarrow said:
My car is now with its new owner, but once I started doing manual calculations I never got below 25 or 26 MPG and the best was just over 28. The trip computer never wavered moved from its average 24.7 across 1300 miles in all the time I had it.

Interesting too that people like me with the old school V8s weren't getting an awful lot less than others with the more modern Merc petrol engines... I guess that's another subject entirely!!
My CLK63 gives the same kind of fuel figures as your 430 it's 25.4 over 2000 miles with a best of 30.4mpg my 55 is actually worse than the 63.