Display accuracy - fuel consumption
 

2.7T

Recently I did some comparison between the displayed (by the ECM) average fuel consumption and the actual consumption.
The actual consumption was measured the common way – gas volume filled divided by the mileage. The actual fuel consumption is in the range of 20% higher than the displayed by the ECM.

Is this a common case or just mine ECM is showing an optimistic data to me?
Do you drive with display on or off?

When the fuel consumption is measured in mpg – US gallons or Imperial gallons are used? What is the average practical fuel consumption you are happy with? (please specify the conditions-terrain, climate, driving habbits, transmission, etc)

RE: Display accuracy - fuel consumption
 

The average will eventually freeze at a certian mileage over a driving time of about 8 hours.
So if you want to get another average push and hold the button on the bottom of the stalk and wait for it to zero out.
When you first start driving it will be as fast as the actual mileage counter is, then it will begin to taper off when it see's your driving style. I tested it against my calculator and my gas reciept and it was only about 2% off in my favor. All in all it was pretty accurate considering i was driving 50/50 highway and city for the test.

RE: Display accuracy - fuel consumption
 

mine hows about 1+mpg better than my actuel fuel consumption. So if it shows 20 avg, my actual is most likely 18.5 to 19mpg

RE: Display accuracy - fuel consumption
 

guys, have you experimented with switches on the cluster - there are switches (4 on mine A6 97) for the trip computer for adjusting the consumption. It can do +10%, -10% etc.

RE: Display accuracy - fuel consumption
 

The gas stations give you less gasoline then you think. This is due to the volume measurement is taken at certain temperature. Therefore, you pay for more gas then you acctually put in your car. Probably that's the problem. :)
If not, I can't explain how 5,4L of gasoline can fit in a 5L container...

RE: Display accuracy - fuel consumption
 

the gauge is a pain and only a guide ( in most cases you have twice what it say ) but its a safety measure

RE: Display accuracy - fuel consumption
 

The computer in my 05 4.2 is usually about 1.5 mpg higher than actual.

RE: Display accuracy - fuel consumption
 

A container usually has something called head room so you can squeeze a little extra into it.

Most gas station pumps compensate for temperature.

Gas is stored in the ground so in the summer it is usually cold. Once it gets in the car it expands as it warms up and if it wastoo full it can actually spill out. That is one of the reasons you should not top off.

As for milage - The MPG is only a relative indicator. I canmake my Audi show 100MPG or 5 MPG depending upon how I play with the buttons and throttle.

The one thing I can quarantee is that when you run out of gas the motor stops running.

RE: Display accuracy - fuel consumption
 

I've tracked gas mileage at actual for every car I have owned - it helps me detect problems. Over the 70k miles I have owned the A6 it has been about 2 mpg optimistic on the computer. It tells me I'm getting 24.6 mpg ona long highway run, but when I fill it up and calculate at actual it is really ~22-23 mpg. That's about 10% off so maybe I'll look into adjusting the computer. Does anyone know the drill for a 2003 A6?

RE: Display accuracy - fuel consumption
 

Another thing to add to this, that's if you are worried about saving a lil bit of money.You should always .....if you can help it, fillup your carat night because of the outside air temp. This is for all seasons, not just the summer.