dragosdor

iTrader: (1)

Hello there Club Lexus community, I am the proud owner of my first Lexus, a 2008 RX350 Brandywine Pearl on black leather no navi and I so love it so far, but while trying to figure out how thirsty this vehicle is, I found out I cannot reset the AVG MPG display unless I refuel.
Is there any other way I can calculate partial trip AVG MPG rather than averaging the entire tank?
It is the first car (in about 12 other brands so far) to have such limitation.

Please let me know if I am doing something wrong or the trip computer is that retarded

RuninRoach

woah! this is weird. I had the same question last night and i logged on today to post this exact question! what a coinkidink!

RX330inFL

Welcome to Club Lexus, dragosdor.

Nope, it is that stupid. You have to put fuel in the vehicle to reset that display value. Besides, the calculation is not all that accurate anyway. Many here find it to be off by a couple MPG.

pauljcl

Not only can you NOT reset it yourself (other than through adding fuel), but you also cannot prevetn it from resetting when you refill with fuel. I guess the Lexus engineers never need to measure consumption other than after a refill and up to the next. When you travel a long distance, you cannot know the avge mpg unless you do it yourself by keeping track yourself of fuel used and miles driven... This is NOT one of the best features of the car...

dragosdor

iTrader: (1)

Agree, as mpg geek as I am, I guess I will just have to readjust to doing the math myself
This is one elementary engineering flaw/limitation. Why do they (the engineers) have to decide for me as to when I want or HAVE TO reset the trip computer??

pauljcl

Particularly since the old RX300 did not have that problem, and you could re-set it at will....

RX330inFL

I believe all of the prior vehicles I have driven with such capabilities could be reset on demand. I think a good question for Lexus would be to ask what they thought they were accomplishing by taking this ability away. Serves no purpose.

dragosdor

iTrader: (1)

I wish there was some hot wire procedure from under dash or hood to reset that )

pauljcl

I'm sure there must be, since the 're-set' is surely an electric signal sent from somewhere. The Lexus manual says that (- I paraphrase, of course) if the refueling is not in some minimum quantity, it will not re-set. So I would guess there is a link in some fashion to the fuel gauge or sender?
But is it worth the hassle? and how accurate would the new reading(s) be?

RuninRoach

Gauge Calculation: 12.2L / 100km = ~ 3G/62.5mi = 20.8 MPG
My Calc: @ $16.73/L cost me ~$1000 to (~60L) fill got 510km off it. 60L/510km = 20G/318.75 = 16.9 MPG

WTF?

Most of this is Highway!!

dragosdor

iTrader: (1)

Redo your math dude! 60l is never 20g. More like 15g.
Therefore 15g/318km is about 21mpg
Lexus computer is correct!
And where do you live to pay $1000 for a tank???

RX330inFL

RuninRoach is in Hong Kong. Uses the same symbol as us. Gas is quite expensive there, as it is in many locations outside of the US. Plus:

1 Hong Kong dollar = 0.1290 US dollars

pauljcl

Also, if they use Imperial gallons, the conversion is approx. 4.55 litres to one Imperial gallons, vs. the 3.8 litres of one US gallon.....

RX330inFL

Price of Shell V-Power, for example, is approx. HK$17.49 per L there in Hong Kong. The price RuninRoach gave is less than that, perhaps a different brand or octane rating, but it confirms we are talking about the same units of measure. The price includes about HK$6.06/L in government excise duty taxes. Prices are also highly regulated and do not fluctuate like it does here in the US.

That is about US$2.26/L or about US$8.54/US Gallon.

A typical fill for me at the station is 15 US gallons. If I had to fill up in HK it would cost me around US$128 (HK$992) plus or minus some change.

15 US Gallons = 56.78L
510KM = 316.9 US miles

So,...

316.9 US Miles / 15 US Gallons = 21.13 US Miles per US Gallon
510KM / 56.78L = 8.98 KM per L

Believe these calculations should be correct for all the questions or comments posted above.

RX330inFL

Not quite sure what conversion tool you are using, but regardless it is wrong.

You can go to Google and simply type in something like the following and when you press return it will give you the result.

convert 510km to miles

Try it, it does work and is accurate.

You can even try more complex computations such as:

convert 8.98 KM per L to miles per gallon