Fuel Mileage Related Discussions
Member
Joined: Jul 2014
Posts: 3,241
From: Shokan, NY
Yes. And the most accurate way to calculate fuel used is to measure how much fuel was pumped into the car. Those two links at the bottom of my last post are articles which explain why the car is not as accurate at calculating how much fuel was used.
Here is another link that has a good explanation of variables that can throw off the vehicle gauge, but would not affect the pump calculation at all.
MPG Accuracy
Quote from link:
"The most accurate fuel estimates occur in vehicles equipped with MAF sensors. Vehicles which use the lower cost MAP sensors have less accurate results. However, vehicles with MAP sensors can provide reasonable results when Volumetric efficiency and injector cutoff are enabled and proper calibration is performed. (Please see the user manual for details) Much of what is discussed below applies to MAP equipped vehicles and less so for MAF equipped vehicles.
The estimate of fuel usage is ultimately only as good as the data received by UltraGauge. Each of the various engine sensors has associated errors. For example, Engine temperature may be +-5 degrees and the accuracy may vary over the temperature range(AKA non linear). Also, the sensor data may have poor granularity. For example, the OBDII Mile Per Hour(MPH) data has a granularity of 0.62 miles/hour. So the possible values are 0.62, 1.24, 1.86, 2.48MPH, etc. If the vehicle was traveling at 0.9 MPH, the value presented to UltraGauge could be either 0.62 or 1.24MPH. In this case, the value has potentially significant error at low speeds, and much less at high speeds. The errors associated with each sensor can combine and the resulting accuracy can be very poor. We have seen results as accurate as 0.01% and as inaccurate as +-13%. Your results will vary based upon your particular vehicle, configuration and calibration.
Some fuels have Ethanol and some do not. The accuracy can change if a fuel with a large percentage of Ethanol is used after calibration with a non Ethanol fuel. For example, you may perform calibration locally where simple gasoline is available. Then find less accurate results on a road trip where only Ethanol blends are available.
Also, environmental conditions can affect the accuracy. A vehicle calibrated in summer may see variation in the winter. For this reason, it is recommended to perform the MPG calibration if the environment changes significantly. It is necessary for the Vehicle's ECM to compensate for the environmental changes in order to minimize emissions. Some vehicles compensate better than others. For those that do compensate well, the environmental variation will have a much less significant effect."
Here is another link that has a good explanation of variables that can throw off the vehicle gauge, but would not affect the pump calculation at all.
MPG Accuracy
Quote from link:
"The most accurate fuel estimates occur in vehicles equipped with MAF sensors. Vehicles which use the lower cost MAP sensors have less accurate results. However, vehicles with MAP sensors can provide reasonable results when Volumetric efficiency and injector cutoff are enabled and proper calibration is performed. (Please see the user manual for details) Much of what is discussed below applies to MAP equipped vehicles and less so for MAF equipped vehicles.
The estimate of fuel usage is ultimately only as good as the data received by UltraGauge. Each of the various engine sensors has associated errors. For example, Engine temperature may be +-5 degrees and the accuracy may vary over the temperature range(AKA non linear). Also, the sensor data may have poor granularity. For example, the OBDII Mile Per Hour(MPH) data has a granularity of 0.62 miles/hour. So the possible values are 0.62, 1.24, 1.86, 2.48MPH, etc. If the vehicle was traveling at 0.9 MPH, the value presented to UltraGauge could be either 0.62 or 1.24MPH. In this case, the value has potentially significant error at low speeds, and much less at high speeds. The errors associated with each sensor can combine and the resulting accuracy can be very poor. We have seen results as accurate as 0.01% and as inaccurate as +-13%. Your results will vary based upon your particular vehicle, configuration and calibration.
Some fuels have Ethanol and some do not. The accuracy can change if a fuel with a large percentage of Ethanol is used after calibration with a non Ethanol fuel. For example, you may perform calibration locally where simple gasoline is available. Then find less accurate results on a road trip where only Ethanol blends are available.
Also, environmental conditions can affect the accuracy. A vehicle calibrated in summer may see variation in the winter. For this reason, it is recommended to perform the MPG calibration if the environment changes significantly. It is necessary for the Vehicle's ECM to compensate for the environmental changes in order to minimize emissions. Some vehicles compensate better than others. For those that do compensate well, the environmental variation will have a much less significant effect."
Member
Joined: May 2014
Posts: 340
From: Los Angeles, CA
I was reporting in the other thread that Fuelly calculated me at 38.9 mpg and my radio read out said the same thing. Maybe the car gives a more accurate read out after several fuel ups?
Member
Joined: Jul 2014
Posts: 269
From: Falls Church, VA
ECON test results
I just posted some ECON button test results in a new thread. AC was off, MPG increased by about 10%.
https://www.fitfreak.net/forums/3rd-...t-results.html
https://www.fitfreak.net/forums/3rd-...t-results.html
Thread Starter
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Member
Joined: May 2014
Posts: 852
From: St Paris, Ohio
I think that the small engine is so sensitive to changes in driving that it will be hard to predict with any close accuracy. Only driving habit and time will tell us what we want to know. Unlike my Dodge Ram 3500 which it didn't matter if I was pulling 25,000#'s or just cruising it basically got the same mileage within about a mile. You could drive all week in the city and then near the end of the tank take a highway ride and boost the gage back up to 36 or 38 only to find it was in reality 30. I'm ok with this as I now know I normally get basically 35 mpg on my typical drives.
Member
Joined: Jul 2014
Posts: 66
From: SANTA FE SPRINGS
My commute per day is about 50 miles total. When econ mode is off I would have to fill up at the end of the 5th day (a bar or two left on the gas tank)
I tested using econ mode on with conservative driving last week and I ended up with just a bar under half on at the end of the 5th day. Sorry my specifics are too specific, but I really just wanted to point out that during my test with econ mode I was bored.
yay
I tested using econ mode on with conservative driving last week and I ended up with just a bar under half on at the end of the 5th day. Sorry my specifics are too specific, but I really just wanted to point out that during my test with econ mode I was bored.
yay
Member
Joined: Feb 2014
Posts: 850
From: The 603
Getting good mileage isn't driving like granny at all.
Member
Joined: Jun 2014
Posts: 142
From: USA
Started using cruise control in the highway, and I have had my mpg shoot way up. Fit LX MT gotten up to 42 mpg easy, might be able to go higher! Driving was hyper mile style, though, boring and coasting as much as possible. Really just trying to stretch my numbers. Really neat, though, I was at 36 going 70 with ac on, went up an instant 6 just by using cruise control at 65.
I'm averaging around 300mpt at this point; I have only filled up twice. I wish I had better numbers to provide; but I know that I had a 2012 Civic LX that I took across country and upon every fill, was getting around 500 mi and about 39.4mpg. Hoping at some point I can get something similar to that with the fit.
Was kind of disappointed to see that the fit only got me around 250 mi in the first tank that I had when brought home from the dealership. Was hoping it would improve but it doesn't look like it's changed too much since. The car is my daily, but it's only driven around 5 mi a day, outside of some activities during the week that are a little farther.
Was kind of disappointed to see that the fit only got me around 250 mi in the first tank that I had when brought home from the dealership. Was hoping it would improve but it doesn't look like it's changed too much since. The car is my daily, but it's only driven around 5 mi a day, outside of some activities during the week that are a little farther.
New Member
Joined: Sep 2014
Posts: 3
From: Las Vegas, NV
3rd time refilling
This is my 3rd time filling up the tank. Still don't know when the gas light goes on, anyone knows? I usually wait till there is only 2 bars left and it's usually 7.5 gallons refilled.
So I'm thinking the bar displays 8 gallons with a 2.6 gallon reserve after all the bars are gone?
3rd time - 275.2 miles / 7.379 refilled = 37.295 miles/gallon (windows rolled down majority of the time with some ac use)
2nd time - was about 32 miles (ac always on)
I mainly drive local as I only live 5 miles away from work. I hope on the fwy for maybe only a mile and the rest is local.
So I'm thinking the bar displays 8 gallons with a 2.6 gallon reserve after all the bars are gone?
3rd time - 275.2 miles / 7.379 refilled = 37.295 miles/gallon (windows rolled down majority of the time with some ac use)
2nd time - was about 32 miles (ac always on)
I mainly drive local as I only live 5 miles away from work. I hope on the fwy for maybe only a mile and the rest is local.
Hope this helps!
Member
Joined: Jul 2014
Posts: 466
From: Arizona
The light does come on; I don't usually fill up my car unless the light comes on (because I like to push the envelope, LOL). I have only filled up twice and noticed the light turns on just before the last bar (it will turn on at two bars but the 2nd bar will disappear as it's lighted up). It usually leaves me with 7.625 galloons to be filled when I do fill at light.
Hope this helps!
Hope this helps!
New Member
Joined: Sep 2014
Posts: 3
From: Las Vegas, NV
Oh okies, that is good to know!
That's what my instructor told me as well when I took an intro to mechanics class but I've always waited till the light come up when I had my first generation Ridgeline for 9 years until someone TBoned me this year and the truck was good. Although I do fill when there is only 2-3 bar left and I'd say that is still about 1/4 tank left only cause it should hold 10.6 gallons and everytime I fill up its about 7.5 or less.
The light does come on; I don't usually fill up my car unless the light comes on (because I like to push the envelope, LOL). I have only filled up twice and noticed the light turns on just before the last bar (it will turn on at two bars but the 2nd bar will disappear as it's lighted up). It usually leaves me with 7.625 galloons to be filled when I do fill at light.
Hope this helps!
Hope this helps!
My mechanic has also suggested to do it because if you're constantly filling at a quarter, you're not excersizing the pump (as eventually over time it will begin to stick at the same level) or clearing the lines and with older cars, you ran the risk of breaking the guage in the dash with the repetition of it never going lower than a quarter. Obviously newer cars do not have guages, so the second doesn't necessarily apply, but I believe him when he tells me it's ok to run past the light.
Maybe he's full of it, but he's been my mechanic for 15 years and he's been handling Honda's specifically since the early 80's.
Member
Joined: Jul 2014
Posts: 3,241
From: Shokan, NY
This is my 3rd time filling up the tank. Still don't know when the gas light goes on, anyone knows? I usually wait till there is only 2 bars left and it's usually 7.5 gallons refilled.
So I'm thinking the bar displays 8 gallons with a 2.6 gallon reserve after all the bars are gone?
3rd time - 275.2 miles / 7.379 refilled = 37.295 miles/gallon (windows rolled down majority of the time with some ac use)
2nd time - was about 32 miles (ac always on)
I mainly drive local as I only live 5 miles away from work. I hope on the fwy for maybe only a mile and the rest is local.
So I'm thinking the bar displays 8 gallons with a 2.6 gallon reserve after all the bars are gone?
3rd time - 275.2 miles / 7.379 refilled = 37.295 miles/gallon (windows rolled down majority of the time with some ac use)
2nd time - was about 32 miles (ac always on)
I mainly drive local as I only live 5 miles away from work. I hope on the fwy for maybe only a mile and the rest is local.
Member
Joined: Jul 2014
Posts: 269
From: Falls Church, VA
I've seen the fuel light come on at least twice. I comes on when the fuel meter only has one bar left. Looking at my fuelly data, it was probably the times that I added 9.00 and 9.22 gallons. Maybe also that time I added 8.53 gallons. No way to know for sure.
