Yes:

The one with the odometer does not reset. The other after a few hours does reset. On a trip, when your stops are under 2 hours, it will not reset. So you will have total time of driving, but not total time of the trip which includes stops.

 

Doesn’t the car calculate mpgs?
What does giving a “like” do?
Just askin.

 

Sure, but I've never seen one that did it accurately. I don't know if it's because it can't, or because the manufacturer build in a 3-10% cheat factor, to make you think mileage is better than it is.

Every car I've had, I record the indicated MPG when I fill up, and calculate the actual MPG based on gasoline usage and miles traveled. The calculated MPG can be off depending on how "full" I fill the tank, but over time, it /must/ average out correctly. Over a 10 year period, a 2006 Avalon showed 1.4% higher mileage than actual. Over an 8 year period, my 2012 GTI showed 5.2% higher than actual mileage. Over a 3 year period, a 2017 Acura RDX showed 2.3% higher than actual mileage. Over only 3 fillups, our new Kia Niro shows 11.6% higher mileage than actual, but that's not enough to tell much. But (un)surprisingly, all the indicated mileages are higher than actual. I haven't yet filled my new E450 wagon, but will be keeping track of it in the same manner. We'll see how accurate it is.

 

rraisley, interesting post. I don't drive the 450 very often, but it is my perception that the instant mpg is based on too short a distance and so it fluctuates wildly. The range calculation varies in a similar manner. My F-Type which I drive more often uses a longer distance for the instant calculation and the range is dead on. When it reads 0 you are out of gas. No cushion whatsoever. The left hand screen on the 450 is set to show the two mpg's and the range.

 

Here is my experience:

• When I drive to Vermont, 250 miles plus, when I start the average mpg is low. As I continue on the Interstate the average miles per gallon goes up. I do not believe it is "instant" but the average over the trip. The reason I say this is when I fill up at about 220 miles, and calculate the actual miles per gallon, done by dividing the miles driven by gallons used (the amount of the fill up) it comes pretty close to the average in the screen. But as RRAISLEY correctly points out, the screen mileage is usually greater by about 1 to 1.5 miles per gallon: So if the actual mileage, miles divided by gallons used is 30 mpg, the screen will read between 30.5 to 31.5 which is about 3% greater than actual.
• What is really interesting is to watch the average go over 30 mpg, note the miles driven and then add to that the range and I often get more than 630 miles range. Granted the E450 has a 21.6 gallon tank, but a range of 600 miles + is insane. The best mileage I have obtained is 33 mpg. Granted the car was on cruise control at 73 mph! If I lowered it to 63 I think I might have even eaked out 35 mpg! Not bad for a 4000 lbs. car with 362 HP!
• FYI, the above mileages I get are done with regular not premium or intermediate grade level gas.
• When the range gets below 40 miles, better fill up: When that happens I have taken on close to 19 gallons!

 

Well, the way average MPG (not instant mpg which can vary incredibly) /should/ be calculated is simply the number of miles traveled divided by the gallons of gas used, for whatever distance it is needed. So Recent would normally be average MPG since you started the car, and Trip or Other (not sure what it's called) would be average MPG since you last reset.

Now Instant mpg, yeah, that varies a lot. And from car to car. I think my GTI recalculated and showed it every second. While Averaging 30 mpg or more, instant could be less than 20 if going up a slight grade, or 70+ if heading a bit downhill. Mercedes shows a bar graph, rather than a digital value, but yeah, it varies widely. And will with most cars.
Instant MPG calculation should (would) never be used for estimating Range. Otherwise, it would vary by a factor of 3 or more in seconds. I don't know what MB or anyone uses for Range. I don't know if they use actual MPG for distances previously traveled, for the last minute, hour or week, use what the car is rated at, calculate what it /should/ give you, or what. I'm guessing it's moderated quite a bit either with previous history or "known" values, or it would be even more inconsistent.

Recently, all my cars have had cushions where the car was not empty when it showed empty. My 1956 Austin Healey 100M, however, had Smith's gauges with little pegs for stops. I swear there was an electrical contact on the gas gauge, because when the needle touched that stop, you immediately heard the electric fuel pump speed up, trying to pump gas which was not there. ;-)

 

The real issue is determining the amount of fuel in a full tank. In my e300 that quantity can vary by about 2 gallons depending on fuel/air temperature and the actual level of fuel in the tank. I sure wish that fuel was quantified and sold by mass (pounds) such as when fueling aircraft. The bottom line is that the actual mpg doesn't really matter that much.

 

I've done that with my GTI, which /recommended/ premium, but I've seen dynomometer tests that it loses only 7 hp, and with my Acura RDX, which /recommended/ premium, but I'm a bit more concerned with my E450 when the manual says:

I doubt I will drive "at the maximum speed", which I assume is over 100 mph, but might want to use more than 3,000 rpm.
tests indicating just a 7 hp loss with regular, and my Acura RDX, which also /recommended/ premium. I'm more concerned with the Mercedes, when in the manual it says:

 

I don't think any car uses the fuel in the tank to determine MPG (although it would for fuel level and range). MPG would be calculated using the amount of fuel used according to a fuel flow meter.

As to the quantity of fuel, I doubt the fuel gauge is that accurate (actually, it might be accurate, but it's rarely linear, so takes a bit of software tom-foolery to get an accurate reading, plus they have to filter the value to keep it from varying too much), but the way fuel is sold is probably just as accurate as with aircraft. Again, flow meters are involved, which are pressure-compensated, and measure by volume. The meters on jet fuel simply calculate and display pounds mass because that's what's important on an airplane. As auto drivers, we don't directly care about mass, but want to know how many gallons we put in our 20 gallon tanks.

Air temperature won't change the fuel density (pounds per gallon of fuel, normally about 6.2), and fuel temperature actually varies the density very little, certainly never as much as 2 gallons. Fuel from a gas station will normally be close to 50-60 degrees or so, depending on location and such, because it's stored several feet underground. A 20 gallon tank will change in volume slightly over one-half gallon for a 50 degree F temperature change, which is usually much more than we see.

 

You live up north where ground temps are lower. I've measured fuel temps at the pump and they vary between 18°C and 27°C. Fuel volume changes significantly between those temps. That said, fuel sitting in a vehicle can easily rise another 12°C with ambient temperatures above 32°C. That was the temp in the shade at my house 2 days ago. Filling the tank is where the 2 gallon variance appears as the auto shutoff on fuel nozzles is inconsistent because of fuel flow rates - high flow = early shutoff. I much prefer avoiding volume measurements for things that should be measured by mass. Even my food recipes specify grams rather than teaspoons, etc. I'm old fashioned that way because I was taught to use the metric system growing up in Iowa during the 1950's. I still prefer it today. The entire world except the US, Liberia and Myanmar use the metric system but road vehicle fuel is still measured by volume, not mass.

/rant

 

So what do you do with the mileage information?

What does giving a ‘like’ do?

 

This is the first I've ever been accused of living "up north" in South Carolina. lol!
I'll admit to never measuring the fuel temperature anywhere I've lived, from here to Syracuse NY. Your 18-27°C is 64-81°F, and I admit to be very surprised that the temperature, even in Florida, would be that warm coming out of the ground. But yes, fuel can easily rise another 21+ degrees sitting out on a 90 degree day. My point was that 21 degrees didn't change the actual volume, or the pump accuracy, that much.
I don't doubt that a bit. One pump auto shuts off, and I can put in another couple gallons. At another pump, I can't get in another ounce after shutoff. Which is why my MPG calculations, based on filling the tank, are not accurate in themselves, but must be averaged over time.
I can't blame you in that. But habit and tradition go a long way, and metric or not, fuel consumption for cars is always in the units of distance per volume of fuel (MPG) or the more logical fuel used per distance (liters per 100 km). And as the pumps measure in gallons or liters, it's likely to stay that way. And I agree about weight in recipes; my wife wanted me to cut 1.5 pounds of apples a couple weeks ago, and insist I measure it as 4.5 cups of apple pieces, as there are 3 cups of apples in a pound. Knowing I can cut them small or large, place them loosely or squish them down, I got out the scale instead, and measured the weight. Surprisingly, this actually upset her, I guess telling her that her method wasn't okay to use.
Yeah, we were all told the metric system would take us over, but it just never happened. Oh, wait: 2 liter bottles of coke! They're just doing it slowly, trying to trick us!

 

Speaking for myself, I record it every tank into a booklet, and end up entering the information into a spreadsheet, to keep accurate track (and yes, graphs) of my mileage, mpg, miles per year, etc. No doubt I'm one of almost none that do that, but most people are interested in the information.
In this case, it's a kind way of thinking a person who helps you out or gives you helpful information. I can afford that.

 

god damn! That’s a sweet looking ride. I have 2019 estate with sport grill and 19” amg wheels and beating myself for not going with classic grill with smaller wheels. The estate looks so much better with your setup.

 

It is a nice station wagon, but,
Every tank? Graphs? Wow. Maybe I’ll try that.

I was asking jtk44 about the likes. I guess it’s a Facebook/millennial/popularity thing.

 

I used to record everything, but it was simply "busy work" with no benefit to be gained.

 

Nah, you probably won't. I'm a retired engineer, and I loves me my spreadsheets! I don't record it into spreadsheets every tank, recording the information in a checkbook registry, actually (works very well). But then update it to the spreadsheet every so often.

It bugs me a bit when I discuss mileage with someone, and they spout off how they get XX mpg, when in fact they only calculated it once, after a leisurely drive, and hadn't bothered to really fill the tank. When I quote mileage, I know what I'm talking about.
I know, but I'm 76 years old, definitely not a millennial or Facebook junkie, but I don't mind being thanked when I help someone, and like to reciprocate when someone helps me.

 

I found a difference, which I'm not that happy about. Every E I've ever seen had dual sun visors: Pull one down, move to the side, and a second is underneath. I've seen it on Sedans and Wagons. I asked about it, and was told all E's had them. But my 2020 does not. It's in the manual for 2020, as it is in the 2019 manual. But it's not there. Bummer. Small bummer, but bummer nonetheless.

 

I always thought the two part sun visors were an example of German over-engineering, BUT they are very useful and often come in handy. I am surprised they were deleted, if they were. Maybe its a parts supply issue. One year the E's were being made for a while with single CD players because MB could not get enough of the four CD players.

I figure if there was an external/visual way to distinguish a 20 from a 19 you would have noticed it. Strange. How do you charge for a new MY without a marker.

 

Back in the day there was no difference between model years for the same chassis style. The model year was determined by the date of manufacture.

 

You mean when Hector was a pup?

 

Plus on the 20s you don’t have the buttons that put down the rear seats when you open the back doors. Gotta hit the buttons in the way back.

 

So, it appears we can tell one year from another by the number of features that have been removed. That's kinda disappointing.

 

I’ll trade my 19 for your 20

 

Nah, I just want your extra sunshades and rear seat fold down buttons. ;-)