Average fuel economy display

[kamiguy]

The display seems to have stopped updating every 30 secs as it used to. It has been stuck on the same figure for a few days now. Seems to be ok when I reset it after a fill then around a half tank or so, it remains static. Average speed seems to be off too(on the same display). Anyone else had this problem?

[herk]

I've noticed it too, but have always figured it to be statistically based. When you first reset the numbers they constantly fluctuate because of the newness of the data. Highs and lows factor in heavily because a standard has not been set. Once enough data has been compiled you won't see much change because the number displayed is a true average. Slight fluctuations in your speed or mpg wouldn't change because mathematically those fluctuations would be abnormalities to a fairly consistent average. When figured into an average the lows are balanced by the highs.

Anyway, that's what i think. If any of you have studied statistics or math i encourage you to set me straight...I went to art school

[Punjab]

Hey kamiguy

see if page 4-10 helps i never really used the screen so if it doesn't help i apologize.

i think the one in the dash cluster is based on overall fuel efficiency and is not real time but i believe the one under info will show real time.

[kamiguy]

Thanks for your info, guys. I am going to watch the info on the nav screen for a bit and see if that reacts differently. I guess my main concern is that the dot matrix display is behaving differently now after about 5k(3000 miles), and doesn't update every 30 secs. Wonder if the on board puter has settled in?

[Punjab]

i rarely see the dot matrix screen change.. only when i go on a 300+mile drive .. haven't reset it from day one over 5k miles.

I wish that it showed me real time speed on main screen, i feel that the speedometer is not placed well .. what do you think ?

[Timmbo]

I've noticed it too, but have always figured it to be statistically based. When you first reset the numbers they constantly fluctuate because of the newness of the data. Highs and lows factor in heavily because a standard has not been set. Once enough data has been compiled you won't see much change because the number displayed is a true average. Slight fluctuations in your speed or mpg wouldn't change because mathematically those fluctuations would be abnormalities to a fairly consistent average. When figured into an average the lows are balanced by the highs.

Anyway, that's what i think. If any of you have studied statistics or math i encourage you to set me straight...I went to art school

herk, you are totally correct on this one. Based on my experience with my '08 Armada and my '09 Murano I belive this to be the case. I personally like the way it functions.

[Mark Booth]

Yep, herk nailed it! The numerical fuel economy display in the gauge cluster is an ongoing average since the last time you fully (manually) reset it. It does NOT reset itself automatically when you fill the tank. Once reset, it shows even the smallest change in average mileage because there is no average data to compare against. Later, when lots of data has already been input into the average, it takes very large changes in the fuel economy to impact the running average.

Mark

[marlin29311]

I agree with Herk and Timmbo and Mark - the system "learns" your average MPG's based on when you start to use that system. This is true of any new Nissan/Infinti with this featuer on the car. It keeps the running average fuel economy over the time that you have driven without resetting it. The more miles, the less fluctuation. If you reset the mpg at every fill-up, you will get the average for each tank of gas that you get.

[kamiguy]

I agree with Herk and Timmbo and Mark - the system "learns" your average MPG's based on when you start to use that system. This is true of any new Nissan/Infinti with this featuer on the car. It keeps the running average fuel economy over the time that you have driven without resetting it. The more miles, the less fluctuation. If you reset the mpg at every fill-up, you will get the average for each tank of gas that you get.

Ahhhhhh it's all starting to make sense now. Thanks for all your input, people. So, the reduced fluctuation applies to average speed too? Is there any point to reset the dot matrix display every time I fill since it appears to display the cumulative data from day 1?

[marlin29311]

If you want to keep track of your tank-to-tank mpg's, it makes sense to reset it. If you want to see the mpg's over the life of your car, leave it the way it is.