Toyota86 fuel readings deviate by approx. 30%
 

Hi, I'd like to share my finding... Hopefully someone can give me some clues on how to deal with this... I bought a second hand gt86, year 2013. I didn't like the performance of the car, but everybody blaims it for being not responsive enough. So I accepted it, as I like the handling. Few weeks later, I noticed that the amount of fuel that I put in my tank was less then what the readings were showings. Average fuel consumption was approx. 15l/100km, but based on the real amount that I filled in my tank, I got approx. 12l/100km. I think the programming has been messed up, in order to reduce the fuel consumption... I can't imagine why someone wants to fool the programming like this, but it explains why my car is very underperforming.
How to found a solution for this? Get the Ecu back to original settings? How to do this?
Thanks.

Computing your mileage any other way than actual consumption is useless, as useless as that mileage computer.

Hi, I agree, but a difference of 30% is too much. Also, the level of the fuel tank is wrong... Reading is showing empty, but still 8 to 9 liter available.

Bad fuel level sensor? Maybe it's confusing the onboard mileage gauge

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was the car modded before you picked it up?

Someone didnt bring it back to stock properly or just completely fubared it....

Thanks, so to start with, I should replace the tank level gauge? Or can it be calibrated some how?

I don't know what happened, but that's also my feeling... The previous owner might have done some experiments and didn't return it to factory settings... How can I find out if it was modified? Ask Toyota to reinstall the original settings?

You can try just wiggling it. It's attached to the fuel pump basket under the rear driver side seat. Maybe it's hung up. I don't know anything about calibrating it or how that would even get messed up unless you're running a standalone computer, which seems unlikely unless your car is very heavily modified

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OK, I will try to access it. Really hope it's not your last suggestion.. Anyway, there must be a solution to restore it back to original... ��

There is something seriously wrong someplace even if you are calculating it to 12L/100KM (19MPG). If it was actually 15 (coincidently that would also be 15 MPG) it is even worse!
That is an absolutely horrible amount of fuel to be using if stock.
I don't think you could drive a stock twin hard enough to get those numbers. In comparison my car that spends about 90% of it's lift at or above 120KPH reads 7.7L/100KM and my manual calculations are always within .1 or .2 of that.
There is something dreadfully wrong if you are actually getting only 12.

Thanks for sharing these realistic fuel cons. figures. I think 12 liter /100km is not that bad, taking into consideration that I drive the car at 160kmph almost constantly. The highway speed limit is 160 in UAE and fuel price is low. When driving at 120 kmph, the real figures are approx. 8liter/100km. The car readings shows then 11liter/100km. I try to figure out why the difference is 3liter/100km.

IIRC this car has a large reserve capacity. As in, when the light comes on there's still loads of fuel left. I've never run it right out, but I'm sure it'll take 52+ liters when dead empty.

As for 15 L/100km that seems unlikely... but I do max 100kph *more or less* on country highway so maybe not the best comparison to your usage. I remember (for a long time) checking the guesstimator in the car vs the gas receipt and actual mileage... I found they were so close the difference was negligible. I regularly get ~7.0-7.5 L/100km and hoon/slide on a daily basis.

Check your actual speed with a GPS/app and compare with the displayed speed and distance

One way it could be that far off is if the speedo/odo is that far off. For reference, mine is within one km at 100km/. Tire size could play a part.

jesus the speed limit is 160 there? I wont be surprised if thats part of the reason the gas mileage is sucking.

Whats the engine spinning at in 6th gear at 160km/h? Its already at around 3k @ 100km/h