Can anyone help me out on this? I bought a certified 2017 Mazda 3 touring standard. I've driven it from Texas to South Dakota and been driving for about 2 months now. I cannot get more than 300 miles before filling up again. Why is this? I've taken it to a Mazda dealership, they did as many tests as they could and found nothing. I use to drive a 2004 Mazda 3 sport standard and always got near 400 miles before filling up. Why is my 2017 getting so much less gas when its advertised as more and a range of 400+?

 

Have you carried out a " miles per gallon" test?

 

Keep in mind the tank on your new Mazda3 is pretty small. My 2009 Mazda3 (same generation as your 2004) could go further on a tank of gas than our 2016 Mazda3, this in spite of the fact the new one gets better fuel economy.

 

It would be interesting to hear how many gallons of gas you are putting in with each fillup in addition to the miles per gallon you are getting. I am only able to put in around 10 gallons in my 2015 Mazda 3 even when the "Buy Gas Now" warning light is on and I am down to 10 miles to empty. I have never figured out if the tank still has a lot of air in it when the pump cuts off or if there is far more gas in the tank when the computer tells me I am out of fuel.

Anyone else experiencing the same?

 

Yeah, same here. The thing is, different cars react differently when it comes to the relationship between fuel level on the gauge and the amount of fuel in the tank.

For our 2009 Mazda3, it is published to have a 14.5 gallon fuel tank; the Low Fuel light would typically come on at around the 11 gallon mark and the gauge would show full "E" at about the 12 gallon mark.
For our 2016 Mazda3, it is published to have a 13.2 gallon fuel tank; the Low Fuel light will typically come on at around the 9 gallon mark and the gauge (and DTE) will show empty at about the 10 gallon mark.

Funny thing, my previous Honda Accord and my current Acura TL (cars built on the same assembly line and sharing a common platform) both have fuel tanks rated at about 17.1 gallons, however, the Accord Low-Fuel/Full "E" would be in the 14.5/15.5 gallon range while the TL is MUCH more conservative in that it hits those thresholds at about the 13.0/14.2 gallon marks. I've discussed the disparity between the two on various forums and basically, that's how the cars behave across the board; the Accords don't complain about low fuel until long after the TL would be annoying the crap out of you about running out of gas. I decided to see how far I could push the tank on the TL just recently and could only hold out for 534 miles before the warnings started getting to me; when I stopped to fill up, I was only able to put in about 14.7 gallons; geez, I could easily have made it to the 600 mile mark if I really had continued milking it.

 

Unless you give the average MPG over several fill ups there is nothing that can point to any unusually problem with your car. Simple as that!

No DTC, erratic engine operation or mechanical concerns means you are getting the best MPG for your driving style,the road you are driving on the condition of your MAZDA and the environment you are operating in.
Frankly I am surprised the Dealership even took your MAZDA without even a DTC or noticeable concern?

MPG is always subjective anyway... most either claim really bad or really good MPG.for any given platform , iIf you pursue talking about everything the concludes the reported MPG you seem to find that both usually end up being exaggerated. ?

 

A real easy way to avoid exaggerating is to just request someone post a photo of the trip computer; not a whole lot of wiggle room in that case.

 

The on-board information from the stored input for calculated estimated MPG in the ECU is for current estimated MPG. The only real way to know the true averaged MPG for a given time period is by filling at the same station and pump , letting the that pump auto shut off , for several fill ups and doing basic math with miles used and fuel replenished. . While the on- board computer information is pretty damn close but because on most MAZDA's and FORDs there is no fuel flow meter and most electronic fuel injection system are a dead head system they are not absolutely accurate for reporting MPG and do not give anything except in the case of most MAZDA's an ongoing estimated averaged out MPG on continued calculated from last input information. Not sure why anyone is even debating the best way to obtain the most accurate MPG? Most all of us have used good old math to figure our MPG for years before and even after engine control modules?.
Otherwise I am sorry but in my opinion most exaggerate their MPG when reporting it on forums.

 

Only partially true. The fact is, OBCs measure at a consistent rate while the old tried and true method of miles divided by gallons is fraught with errors due to inconsistencies of when fuel pumps click off. The very best way is to track fuel economy is to validate the OBC against a minimum of five to ten tanks of fuel. Once done you can come up with a standard error for the OBC, which in turn can be applied to any given tank for a MUCH more accurate representation of that individual tank's economy. Case in point, I've tracked the last 10,000 miles driven in my TL; the OBC reports a running average of 26.7 mpg while the miles divided by gallons results in 26.391 mpg; effectively over-reporting my fuel economy by 1.2% (pretty accurate in my book).

Looking at a recent tank where I covered 534.8 miles, the OBC reported 36 mpg, gallons at the next fill up were 14.883 which yields 35.934 mpg; well within the 1.2% delta.

 

lol
I should have included the temperature variant within 10F degrees but didn't think about it at the moment..That illuminates almost all "inconsistencies" in the pump shut off. .
Look for the states certification on the pump and then look up the States log about that station. Lot of interesting information that can cancel perpetuated MYTH about fuel pumps in the US in most states.
Also I see that you included hard math which I also did and the percentage is pretty much what most would get when comparing. So while you had to re-respond again with almost what I have said it appears we BOTH are posting almost the same thing. Compare OBC with hard math to get a better indication of average MPH. And it comes back to my conclusion once again the most people that report MPG on forums DONT do this and therefore as I keep saying IMHO "exaggerated" figures.