Accurizing car-calculated fuel consumption
Thread Starter
Burning Brakes
Joined: Sep 2022
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From: MSP
Accurizing car-calculated fuel consumption
Actual fuel economy versus displayed fuel economy have never been in the same ballpark on my 2018. It'll say 25-27 and reality will calculate to 18-20.
Has anyone looked into this ever? I've had other cars where you can adjust the calculations to make these readouts accurate. Is this something that can be done on a Chevy? Through HP Tuners or anything similar?
The speedometer is perfectly accurate, so it's not a matter of changing that setting.
Has anyone looked into this ever? I've had other cars where you can adjust the calculations to make these readouts accurate. Is this something that can be done on a Chevy? Through HP Tuners or anything similar?
The speedometer is perfectly accurate, so it's not a matter of changing that setting.
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From: Jacksonville Florida BWO Dayton, Cincinnati, Bloomsbury NJ, Cincinnati
2015 C7 of the Year Finalist
Actual fuel economy versus displayed fuel economy have never been in the same ballpark on my 2018. It'll say 25-27 and reality will calculate to 18-20.
Has anyone looked into this ever? I've had other cars where you can adjust the calculations to make these readouts accurate. Is this something that can be done on a Chevy? Through HP Tuners or anything similar?
The speedometer is perfectly accurate, so it's not a matter of changing that setting.
Has anyone looked into this ever? I've had other cars where you can adjust the calculations to make these readouts accurate. Is this something that can be done on a Chevy? Through HP Tuners or anything similar?
The speedometer is perfectly accurate, so it's not a matter of changing that setting.
Elmer
Thread Starter
Burning Brakes
Joined: Sep 2022
Posts: 1,202
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From: MSP
At that instant in time, you are getting 25-27. Your manual calculations are averaging in the traffic lights at 0 MPG, thus you get 18 - 20. So, if you could cruise, not slow down and don't stop for any lights, you would manually calculate 25 - 27 just like the car.
Elmer
Elmer
The instant readout is also dubious at best, I reckon.
Team Owner
Joined: Jun 1999
Posts: 41,792
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From: Houston,Texas USA
My 2015 coupe, and the 2019 GS coupe are both the same when filling up with gas.
The calculated gas mileage is 1-2 mpg lower than the display.
The fuel used is usually a gallon plus, more than what the display shows.
The calculated gas mileage is 1-2 mpg lower than the display.
The fuel used is usually a gallon plus, more than what the display shows.
Pro
Joined: Jul 2018
Posts: 609
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From: Norman, OK
It seems very odd that your estimated fuel efficiency is so far off. Like Tom/99, mine is 1-2mpg optimistic but your car is very optimistic. Have you changed injectors or done any other mods? The computer is calculating the efficiency and I'm not sure if there is a flow meter in the fuel line or if it bases it on RPMs and throttle position. I would suggest tires being off but your speedometer is accurate so it's not that side of things.
Thread Starter
Burning Brakes
Joined: Sep 2022
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From: MSP
The car is stock as far as I am aware, though the previous owner did have it lowered quite a bit below stock ride height. That's since been fixed. The engine bay looks stock, and aside from the idle clatter that I can't get anyone to acknowledge yet and the "normal" idle shake these cars have, the car seems to be running fine.
I've had a couple tanks that were closer, like ~3 mpg, but it's usually pretty far off. On my road trip when I bought the car the DIC said over 30mpg for a whole tank of nonstop freeway, but the the reality was around 25.
I've had a couple tanks that were closer, like ~3 mpg, but it's usually pretty far off. On my road trip when I bought the car the DIC said over 30mpg for a whole tank of nonstop freeway, but the the reality was around 25.
Thread Starter
Burning Brakes
Joined: Sep 2022
Posts: 1,202
Likes: 569
From: MSP
It seems very odd that your estimated fuel efficiency is so far off. Like Tom/99, mine is 1-2mpg optimistic but your car is very optimistic. Have you changed injectors or done any other mods? The computer is calculating the efficiency and I'm not sure if there is a flow meter in the fuel line or if it bases it on RPMs and throttle position. I would suggest tires being off but your speedometer is accurate so it's not that side of things.
The coded injector flow map being inaccurate is the only reasonable explanation, which is common as a car ages and why there are trim maps. At 18k miles I'd be surprised if the injectors are flowing that far off from the factory spec, though.
