I have had my 2010 fit sport automatic for a month and a half and have made five fill ups so far. I noticed once early on that the computer said higher than my measured fuel economy and later I started noting what the computer said and it hasn't been that far off. It has even said lower than my measured economy. My last two fillups I have noted the indicated when filling up. Here are the results so far. Measured 36.3, indicated 35.3: measured 31.5 indicated 32.3. Is this in line with what 2009 owners experience? because I have read that the computer indication is consistently 3 to 5 mpg high on 2009 model. I know that on my best tank measured at 40.5 the computer was indicating below 40 but I didn't make a note of exactly what it indicated. I know this is a very small data set and my fit is still very low miles (~1200 mi) so is this something people saw while breaking in their 2009's or did honda actually fix this?

 

Those are close to the same #'s I calculate. My computer is usually 3 mpg higher but I think honda fixed it's software to more closely match the real mpg mid last year. I know there is a service update on a software update for the MID somewhere on this forum. Its not a big deal to me so I'm in no rush to get the software update.
To answer your question though the 2009 Fit and 2010 Fit will get the exact same gas mileage. The computer might be slightly off depending when you got your Fit but when it comes down to it they both sip the same amount of gas.

 

I had the update done to my '09 on Nov. 25. before, my mileage computer was 10%-15% high. Since the update, it's been within 3%.

I'm pretty sure the 2010s got the fix from the factory. Your figures are similar to what I'm getting since having the software update.

 

Mine has been optimistic 3 or 4% per tank so far

 

yours had the fix right from the factory.

your numbers clearly verify it.

 

Would the dealership install this software update free of charge when I go in for my 30,000 mile service? Do I need some sort of printout/form to take with me or will the dealership just know about this fix? Thanks.

 

How do you manually calculate your mpg? How do you know exactly how much fuel you've used in x miles?

 

Me? I fill to the second click (first click, wait a while, fill to second click). I use the same station, fill at about the same time of day. I reset my trip meter after each trip.

 

I don't do that much, but all I do is subtract how many miles are on the clock from the last time I filled up abd divide that number by how many gallons just went into the tank. (I keep a record of every time I stop for gas)

 

Browse All Cars | Fuelly

 

Honda Service Bulletin 09-086

Fit MPG

 

Thanks alot. I understand how fuelly is doing it now.

You need to fill your tank to the brim though. That is still extra mass you need to carry around wich could possibly hurt your mpg.

 

I fill my 2010 AT to the brim on each fill-up, and the my actual mileage has been within .5 gallons of the mpg indicated on the display every time (6 tanks so far). Amazing- how does the car calculate? Is fuel flow actually measured- cause that would explain it..

 

Thanks for the info everyone I had no idea that honda had updated it's software. Good to know.

 

Gasoline weighs approximately 2.69 to 2.91 kg per gallon. The Fit/Jazz has a 10.6 gallon tank.

So a full tank of gasoline weighs approximately 31 kg.

The fuel consumption for carrying an extra 31 kg is trivial.

Besides, keeping your tank full reduces the chance you will get condensation in the gas tank (aka water).

Keeping a full tank of gasoline has additional benefits as well. The fuel pump is immersed in the tank and its design utilizes the gasoline in the tank as a heat-sink (aka to disperse the heat generated by the operation of the motor in the pump).

The cooler the pump runs, the longer it will last (in theory at least)

 

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Not a theory, a fact. When i started a cross country trip with my 1995 Dodge ram (fuel pump in tank also) (trip was in 2003), when the tank level got to half, I started having problems. If I would step on the gas past a certain point, the truck would bog and cough. That point eventually got closer and closer to idle until the truck stalled and I could not restart the truck until the pump cooled.

This was OBD-1, so no codes were set for it. I called a buddy who works as a mechanic at a Chrysler dealer, and he told me it was the fuel pump. It was old, and when it got hot, the pump slowed down and reduced fuel pressure until there was none to run the truck.

Took it to a dealer, had them check it out, they could not find anything wrong with it. I had them replace the fuel pump. 8 days and 4000 miles later, I had no problems.

A little off topic, but proves the point.

 

There is no need to fill the tank right up to the filler neck; if the fuel expands due to warming, the purge canister (supposed to catch fuel vapor only) will be overloaded and cause problems.
If you are determined to check your mileage manually, doing it over time will level out any inconsistencies from how full the tank is on a given fillup.

Yeah, the fuel pump wants to be immersed in fuel to keep it cool, but if you have to keep the tank half full or better all the time, there is something else going on.

Most current gasoline has 'dry gas' as part of the mixture to absorb any condensation that forms in the tank.
Moon

 

Hello, I am living in Germany and own a Fit (it is named "Jazz" over here). With the 2009 model the owners have a problem with the Fuel indicator and I wonder, whether this problem is similar to the problem you mentioned here below. What happens here is, that the multi information display makes pling (when driven about 500 km) and tells you that you have to find a filling station soon and that you can drive no more than 50 km. When you fill the tank (whose capacity is 42 liters) you can put in only 28/29 Liters .... means under normal circumstances one should be able to drive another 200 km.
Honda tells that this is a well known problem because of the tank, which is situated under the front seats. They like to solve the problem and work on solutions ... but this takes already months. Next thing is, that Honda says also not to drive more than the remaining 50 km ... what would mean, that only 70% of the tank capacity is for use.

I wonder, whether you experience the same problem and whether Honda in USA or elsewhere was able to solve the problem.
Hopefully I could express myself and the problem good enough!

I would be gratefull for any information on this. Thank you!

 

Hi Emily,

No, that problem does not exist here. Our multi information display gives no estimate of remaining range. Our Fits don't have a noise (pling?) but they do have a low fuel warning light that comes on at about 3 to 5 liters remaining. I think this is good.

The only problem we had is the multi information display was calculating better economy (Miles per Gallon) than actual. There is a software update to US 2009 models to correct this (details at this link) but this does not describe your problem.