c230coupe

This is the first time I am driving a car with a "real-time" mileage display.
I am curious.. how is the mileage measured and how accurate is it. Are the numbers preprogrammed or does it actully measure fuel flow, rpm, gear, etc.
I am getting 33 mpg. @ 65 (6-spd)... is this right?

What average are most people getting on a 2002 c230k..

Vik

TimmyC230boy

I havent reset my milage counter in about 2200 miles. I have a running total of 24.3 mpg. But I drive 90 in city and I drive pretty hard.

avlis

My guess: it measures the fuel flow vs. speed.

I average about 26mpg per tank. My driving varies from stop-n-go to setting the cruise control at 90+ mph.

session

wouldn't it just measure the ratio of fuel volume in the tank versus the distance you travel? measuring fuel flow seems very advanced for such a simple calculation.

anyway, living in northern virginia traffic i only average about 21 mpg. i HAVE reached 32mpg (and a range of 428 miles) on a long interstate run.

avlis

Session, In my first post I should have said flow vs. distance.

At first thought, I assumed it measured fuel volume. The reason I think it mesaures flow is because the display updates quite often, every couple seconds or so even while accelerating and decelerating. I would think the fuel level sensor would give inaccurate readings when the fuel is sloshing back-and-forth in the tank.

Another guess on fuel flow: Maybe the computer knows flow rate based simply on throttle position and/or maybe even injector timing. I think measuring flow is simpler than you think.

session

measuring volume is not so volatile... your fuel tank gauge isn't constantly going up and down

zpeed

Once I go up and down a small hill. On the way up I see distance show 12 M and on the way down I saw 70-80 M.

vinmanc32

You would all have to send me some napkins to clean up after myself. I get about 23mpg on a great day and about 18mpg on average. Im not *****in about it but it must be nice to get consistently over 25.

session

i thought i was alone

mdp c230k

I do all my driving in town and only go two miles to work each way and I get a big 13mpg! If I do go on the highway I get 30mpg. It all depends on your foot at stop lights, mine is very heavy!:p

avlis

I think the fuel gauge is designed to give a slow reation to changes in the level. The sender takes and average of the level when the stuff is sloshing around. This prevents the gauge from bobbing up and down when you hit the brakes.

Anyway, what I'm trying to say is the amount of fuel used in a couple of seconds is so small that it can't possibly be measured by the fuel level sensor in the 16(?) gallon tank. Or, at least, that's my story and I'm sticking to it.

MB-BOB

Session, vinmanc32 has nearly 90% more horsepower in his C32 than you do. So he gets to go to the gas station more than your do. But he also gets to smile more when leaving the stop lights behind.

Your gas mileage should improve over several thousands of miles. My sedan has 12,000 miles on it and the mileage seems to improve even now. Someone else posted here that mileage won't level off until you have about 20,000 miles.

I believe the mileage computer measures fuel flow, speed, elapsed time compared to mileage from start, and idle time at stoplights to approximate the mileage... probably other variables, too. I track my mileage on the home computer, and I get slightly less than what the car's computers say. Currently, my 3.2L car is getting about 22.5 mpg tank-to-tank average. When new, it was about 18 mpg.

Using the A/C doesn't seem to affect power in my car, but saps the mileage about 2-3 mpg.

session

i'm dumb and didn't notice he had a C32.

Outland

Ive been running around 22-24 in the city, and 29-32 on the hwy. First week of ownership saw a miserable 13mpg, but I think that was due to way too much hammering the throttle :-)

petercrase

FYI, The "after start" screen on the 2002 C230K Coupe resets itself after 4 hours of the car sitting and not running. The "after reset" screen resets itself after 40,959 miles or 99.59 hours, whichever comes first. Unfortunately the "after reset" screen cannot be used for cumulative mileage beyond 99.59 hours of running time. On my coupe, that self reset first occured at about 4000 miles, then again at after another 4000 miles had elapsed.

vinmanc32

I am approaching 11k now and do notice the mileage is better than it was at 7k. I have actually seen it hit 23.8mpg!!! I was on a long ride and average speed was about 75 to 80. But then reality hit, and I noticed it back to 18. But nothing like leaving those red lights and watching everything in your rear view getting smaller and smaller. The sacrifice we must make.

MB-BOB

It's interesting to know that "after reset" does so at the times/mileage noted, but mine never approaches these values.

I use the "after reset" computer to track tank mileage. Write down the avg MPG, and avg Speed readings and reset to zero with each fillup. This gives you a more accurate reading of mileage over the course of a complete tank of fuel, compared to the "after start" computer, which is usefull mainly for same day data.