Hi i've read your post about your dealer having filled your tank with low octane fuel. In my case I bought my Scion or FT 86 cause i'm in argentina, I took my new car of the dealer a couple weeks ago.
But to my suprise, the ECU at first showed an average of 50 Litres / 100km and I SAID WHAT!!! it's shown in Litres per 100km not in MPG. Then it came to my mind could this unit be defective?
Am I pushing the gas pedal too much .. too much revs? not really cause I was way below 3000rpm. Thing is I didn't travel that far with my car, only did city trips to the supermarket didn't take it to the highway.
Then I said well I might no be doing a precise timing on shifting the gears.. So i enabled the G-on which shows on the dashboard the gear you're in and and a small triangle blinks when you got to make the other gear..
Well it helped a bit the ECU showed 25 Litres/100km .. but it's still TOOO MUCH!
SO what's going on with my new car? is the ECU Faulty? could the fuel my dealer filled the tank with be of low octane and is influencing the fuel consumption? don't know what else to do . please hep me out
thanks

He is correct, the ecu will adjust itself over time. but if you want, just reset ecu by doing what he said above.

btw, I am a certified EFI tuner

Can someone help on my previous post.
Thanks

That calculation is most probably off. Have you reset it?

Hi what do you mean by having resetted it ? help me a bit here.

Update: I think you may point to resetting the dashboard MPG function, which I did actually. And the values changed from 50Litres / 100km to 25litres for every 100km.

Cycle through the display until you see the avg fuel consumption. Consult the owners manual on how to do this. Then press & hold until it zero's. You have now reset the average fuel consumption monitor. If you do this at the beginning of each fill up, when you fill up next time the reading is the approximate average for that tank of fuel. If you never reset you are getting an average since the last time it was reset.

The FRS/BRZ has a very broad band of fuel consumption depending on ambient conditions and how you drive it!

Hi yup I did already reset the avg fuel consumption monitor, which in my case tells you the average but in litres per 100km. I've resetted it when It showed like 50 Litres for every 100km which was a complete nonsense.
But I had the tank filled completely by the dealer. I setted the trip B option to 0km when I took the car out of the dealer. and I measured the first quarter of the tank which would be equal to 12.5 litres. I only did 36KM. That really annoyed me. Then I enabled the G-on function which tells you how to shift gears.. after I did that the fuel consumption monitor went from 50 to 25 litres/100km but it's still being too much.
any ideas? My car is brand new

The avg fuel economy will be really high for the first 1/4 tank as it there isn't enough data (Km's driven) to bring down the avg. Drive it for a couple of tanks worth and re-check the avg you will find that it will be reading much lower 10L/100km or less. Mine reads 8L/100km and I have a heavy foot :-).

The current fuel consumption will read as high as 50L/100km to as low as 0 while driving, this is normal.

Monitor it yourself.

Fill up, reset your trip "a" or "b" and if you don't get atleast 500km per a tank of super gas, you have a major problem. You could also try disconnecting your battery to reset your ecu. More likely it's a faulty mpg device than your actually going through that much fuel.

guys thanks for all your tips. I'm going to recheck again, re fill tank entirely. I talked with the guy from tech support of the dealer.
I told him about the fuel consumption that I did 1/4 tank and had 36km and he said that's far from acceptable.
I told him I was given the car with the tank filled up. But he said maybe it wasn't topped entirely.. so he said to go and fill again the tank to be sure it's completely filled though I could see the needle reaching the top of the tank it might not be filled. So as to be sure.
Then drive it again.. and see if the Litres per 100km do change on the ECU.
But I'm going to do like you guys say. Thanks again for all your tips. I was getting worried I had a faulty unit :(

Something I forgot to tell you all, is my car came with R16 wheels Yokohama not R17 (Michelin), could that impact more fuel consumption I inflated with 35 PSi.

How many km's have you driven? I don't think you've driven the car enough to concerned about the gas mileage yet. Cars usually get better mileage after break in, keep track of it for awhile longer, see if it's meeting expectations after a month or so. I can't imagine judging a car without going a full tank which should be 200-300 miles (around 350-450 km).

Also realize that how and where you drive has a HUGE impact, some members report they don't get any better than 20 mpg (about 12 L/km), in stop and go driving like you describe (no highway) you're not going to get great mileage.

Well then I would suggest that you try a little less throttle and shift below 3000 rpm for a tank and see what results you get. Gord-zenith is right about the fuel consumption can be high in the first part of the tank. The more starts from stop in first 1/4 tank, the worse the average, while the average will come down with longer highway runs. Try monitoring your driving with the FE monitor set to instantaneous to see what results you get and gauge it relative to your driving style. I think then you may be better able to see what is going on. If you are getting high instantaneous numbers all the time you won't get low averages!

The best average I have seen is 5.0/100 km after 100 km of pure highway driving at 100 kmph through foothills. My worst average on a fill is around 9.1L/100 km. lots of winter, very short city trips. And that is from fill-up calculations, not the computer.

Please do yourself a favor and stop gauging fuel consumption from the dash meter.

It is not at all accurate.

-alex