Coast down a long hill in neutral if you want to see that MPG figure go high!

 

what goes down must go up

 

Hah, last weekend I got 63.1 MPG for 36.3 miles. It helps that I was coming into Denver from the mountains.

 

Is anyone else comparing the gauge's MPG display to what they're actually getting (based on calculating it yourself)? I feel like I'm pretty consistently getting 2-4 MPG worse in reality than what the dash is displaying. Once I got relatively close (within 1 MPG) but I've never actually had my MPG actually work out to be above what the gauge displays.

I wouldn't have an issue if it was just a matter of it sometimes being above and sometimes being below. But the fact that it's ALWAYS less seems like it's cheating.

 

I've been calculating mine manually (I've been using the "ACar" app for years) since I had the car (35,000 miles now) and it has almost never matched or exceeded the in-car computer's "measurement". I too have typically been 2-4 worse, consistently. Someone last year explained that this has something to do with the kind of sensor in our car which had it been something else it would have allowed for a more accurate measurement. I know nothing about this, I just accepted it as probably true. That thread is still somewhere in the history. I've learned to make the mental adjustment and assume I'm probably actually getting about 3 MPG worse than what I see as I'm driving along.

 

My experience is similar to Robbb's: The display results is typically 1-3 lower that my calculated results. Only about 10% are they very close.

 

I still have to add up the numbers but all I know so far on my first fuel up the computer said I had 12 miles to empty. When the pump stopped it said I put 8.5 gallons of gas in. Don't we have a 10.5 gallon tank? If my numbers are right I think I could of made it another 60 miles easy.

 

It's actually 10.6. The range estimator is not accurate at all.

So I usually drive where the setting shows MPG for Trip meter A and how many miles I've driven. I do some mental math going by the MPG number that the car is giving. So if it's estimating 40 MPG and I've driven 380 miles, I should probably look for a gas station because 40 miles per gallon x 10 gallons is 400 miles. Obviously more but that should safely get me to a gas station before I run out of gas.

 

Thanks for the info. I will give that a try and carry a fresh gallon of gas for any mishaps until I get it down. I never liked those computers. Another car in the family, a Pontiac G5, the computer would just shut off and go from 40 miles left to 'low fuel'. It's like what is this. If the technology isn't there to accurately gauge it then don't.

I was really unhappy with the first tank/mileage until the pump said I only put in 8.5 gallons.

 

The gas gauge says empty and the range says 0 when in reality we still have 2.5 gallons and 50 to 100 miles left. It was discussed a while back in this thread that this is so procrastinators don't run out of gas and also because it is unhealthy for the car to run all the way to empty. Apparently the trend now with modern cars is to tell the driver they need to fuel up long before it can become a problem so that people don't get stranded.


I'm looking at my 74 fill-ups on my Fuelly dashboard where I track all my gas consumption. My longest trip on one tank was 406 miles using 9.218 gallons at 44.04 MPG. The most I have filled is 9.9 gallons but I usually pump 8 gallons.


The trip computer is usually about 10% higher than actual. I suspect this is because the trip computer average becomes skewed when coasting downhill for a long period of time. The Torque app only displays up to "255+", well before I reach my maximum coasting speed, I suspect the trip computer also has trouble calculating an accurate figure when travelling at high speeds at idle, maybe that's why the trip computer is too high. Just a guess.

 

I wanted to share my best ever MPG for one trip as reported by the trip computer. 63.9, with the previous trip 55.6 MPG. For both trips, the engine was already warm, dropped in elevation by 200 feet over a distance of 7 miles (both trips), best possible road and traffic conditions, drove slow, A/C off, on over-inflated tires, seldom using the brakes. It is still possible to get 54 to 55 MPG (trip computer) without dropping in elevation with recommended tire inflation, I have done it several times. Having 40 PSI in my tires only seems to increase my mileage by 1 or 2 but sure does make the ride bumpy.

 

It calculates ridiculously high mpg perfectly well, it just can't display those values in real time. That's not what throws off the cumulative calculations.

 

My Fit is rating pretty low on charts, it is 4 months old, and my daily driving is short, 4.5 km to work, 4.5 km back, and on weekends, I move around in the city only. Have not taken it to the highways yet.

My city is a nightmare in traffic, a lot of bumper to bumber traffic, a lot of stop and goes.

 

One thing I have noticed with Fit is, driving habit makes lot of difference. If you are drive slowly and keep it in and around green zone, you can easily see 35-40 mpg in city traffic as well. On freeways anything above 70 mph, mpg falls apart.

 

Stop go is not good for any car fuel usage, if your only 4km from work maybe you can ride a bike or catch public transport, 4km is very close you'll have very high fuel consumption on those such short trips, your using more fuel just to start the car then to drive that trip.

 

Maybe get a bike, public transportation is no option here. I will try to stop using A/C for two weeks if that helps, it will be challenge in this 30ºC humid weather.

 

How much can cold temp negatively affect mpg?


My filter was filthy so I swapped a k and n. That same week temp dropped and my mpg went from 37.xx to 28.xx.


Debating going back to a Honda filter but I was curious if colder temps could affect it this much.

 

https://www.fueleconomy.gov/feg/coldweather.shtml

My MPG always dropped on my 5-speed Toyota Matrix in the winter and I expect the same with my FIT. Snow tires also affect MPG.

 

Ok I took my fit to the highway for the 1st time (never had the chance before) and it estimated 24 Km/l (56.4 mpg), so definitely my daily driving habit takes its toll on efficiency.

 

Cold air is denser, so it huts twice: it's harder for a puny engine to push an unaerodynamic car through and more of it gets inside the engine to burn gas (that's why cold air intakes sell).

Cold air also keeps things from getting up to operating temperature, leaving you running rich in an effort to warm up. Or even worse, letting it idle to warm up: the zero mpg you get in the driveway hurts your tank.

And all that's without the winter gas mix.