gas mileage

[zchad]

I just purchased a 2004 Prius with 40,000 miles. I drive 100 miles a day to work and back. 70 percent of that is interstate driving. My frist tank I only got 255 miles. When I filled up it kicked of at 7 gallons, but I was able to continue pumping to 11 gallons. Can anyone give me an idea of what I need to do, because my math comes up to 23 MPG way less than I expected.

[berylrb]

<div class='quotetop'>QUOTE(zchad @ Feb 5 2007, 04:43 PM) [snapback]385705[/snapback]</div>

I just purchased a 2004 Prius with 40,000 miles. I drive 100 miles a day to work and back. 70 percent of that is interstate driving. My frist tank I only got 255 miles. When I filled up it kicked of at 7 gallons, but I was able to continue pumping to 11 gallons. Can anyone give me an idea of what I need to do, because my math comes up to 23 MPG way less than I expected.
[/b]

Hey welcome to priuschat zchad!

Realize that since it is your first fill-up it won't be very accurate unless your method of filling was the same as the previous tanks. Here are some factors that contribute to that 23 mpg:
•outside temperature
•gas station of choice
•pumping speed (our pumps have three settings I always choose the slowest)
•the previous could have been reset by accident, say at 112 miles, so you could have had 33 mpg

So on your next tank try to use the same station, same pump speed and I bet you'll easily be 40+ mpg!

The best to you!

[MegansPrius]

<div class='quotetop'>QUOTE(berylrb @ Feb 5 2007, 06:46 PM) [snapback]385738[/snapback]</div>

Hey welcome to priuschat zchad!

Realize that since it is your first fill-up it won't be very accurate unless your method of filling was the same as the previous tanks. Here are some factors that contribute to that 23 mpg:
•outside temperature
•gas station of choice
•pumping speed (our pumps have three settings I always choose the slowest)
•the previous could have been reset by accident, say at 112 miles, so you could have had 33 mpg

So on your next tank try to use the same station, same pump speed and I bet you'll easily be 40+ mpg!

The best to you!
[/b]

Also, the Prius gas tank uses a bladder and can be different sizes at different temperatures. For a cool post with photos explaining this, see http://priuschat.com/index.php?s=&show...st&p=359097

With a Prius, I've found I'm never putting in the same amount when I hit 1 square on the tank display. Usually I'm putting in from 7 to 9.5 gallons.

What mileage did the MFD show you getting?

[sanguis]

<div class='quotetop'>QUOTE(zchad @ Feb 5 2007, 06:43 PM) [snapback]385705[/snapback]</div>

When I filled up it kicked of at 7 gallons, but I was able to continue pumping to 11 gallons. [/b]

someone here once reported that it's best not to over-fill as the pump's vapour recovery system may actually take the spill-over gasoline that you paid for. Did you stop at 11 gallons just because you knew the tank had an 11 gallon capacity ?

I've never put more than 10 gallons in (either on hot or cold days).

[coloradospringsprius]

zchad, by far the most likely explanation for your 23 mpg is that the tank wasn't full when you got the car. Therefore you put in more gas than you'd previously used. (Remember, you got it from a dealer who probably filled it exactly like you did at first - letting the pump stop at seven gallons.)

What was the mpg on the display? It tends to be fairly accurate (mine runs about 2 mpg high). As you'll learn, it's difficult to get a consistent fill on the Prius, so the computer calculation is usually more accurate than the pump calculation for any given tank. Over time, the two calculations will be very close.