Fueled up for the first time tonight

it will go up from your first tank especially if you start taking advantage of the different driving techniques, my first tank was 48mpg and now 5 tanks later that last two have been in the 60's with my lifetime average now up to near 56mpg.

 

I've almost finished my 2d tank of gas. Oh how I remember that first fill up! It was over 2 weeks ago, but I remember the feeling as if it were yesterday. (with my old car, it WOULD have been yesterday!)

Enjoy! I sure am.

 

I've had the car for 2 months and am now on my 6th tanks, but i have yet to spend the ammount of money or filled up the ammount of times i had fill up in my last car in just one money, in two months i've spend 192dollars on gas, still have a hundred to go before i match what i spent in a month before. (Had a sports car that only got 18mpg)

 

Its not the pump.
Your moving to another pump allowed the tank to vent a little.
After a year of ownership I have found the best thing to do is to let the fuel tank vent a little before fueling. I have had only one gas belching episode and have since let it vent a little and its been fine. When you arrive at the gas station open the gas fill...do not insert pump. Go inside and get a drink or whatever. By the the time you come back it will be ready to fuel. Works every time now. Fill on slowest fuel setting and hang up the pump on the first click off. Do not attempt top off. Always fill up when your down to 2 pips.Good Luck!

 

He's right, there have been a few times where mine has been in the sun all day, and I needed to fuel up in a hurry and from empty only been able to get 6 gallons or less in. On my previous cars those would have been the days that when you unscrew the gas cap that you would hear the gushing of vapors escaping.

 

What you are doing is evaporative cooling of the tank, so that the undersized vent system can better handle the incoming fuel and resultant flashing. Makes sense on a hot day, and is completely counter to what the design is supposed to accomplish (reducing fugitive emissions.)

EDIT: An interesting aspect of this problem is that in some hot conditions it could start out almost independent of fuelling rate. If the tank and fill line are hot and trying to off gas, then adding a small amount of fuel is still a problem because it will still have about the same vaporization rate to start out. This is likely to produce enough back pressure and perhaps enough splashing toward the nozzle to seal the venturi inlet, shutting off the nozzle. So if one waited to fuel, allowing the system to vent/off gas and thereby cool, the resultant flashing vapor velocity might not exceed the system limit.

Hmm...this brings me to another consideration...some of the vapor return nozzle designs for Stage II vapor recovery areas might work better as they have built in ability to handle vapor counterflow. I've seen pics of some that have more holes and could perform better if my hunch is correct. The devil could be in the details of the nozzle design. That might help explain why some are so insistent that this is all "operator error"--if they are in areas that have a different nozzle design.

The number of possible scenarios for this system to fail is staggering.

 

Thank you yes sir your right too with your observation of the air gushing
on older cars. You'll never see that on the Prius as the fumes are trapped
and re-cycled I would imagine and that other poster is correct too in my venting of the tank I am doing what Toy's Engineers exactly do not want me to do and thats venting fumes in the atmosphere. But I beleive if I don't I won't be able to successfully fill the tank without fuel pouring out which is probably worse atmosphere wise. I think Toy's Fume recovery system in the tank is to tight. Probably to meet there 0 Emissions mission.
Or maybe with the fairly recent installation of E10 everywhere maybe thats creating a fume problem the car was not designed to handle. Just reaching here.

 

+1. My Prius does better than my 900. Even with the cold air in our area now, I am still getting a little over 51 mpg.

 

Just got back from a trip to Chicago from Dayton, OH, 310 miles each way. Waited until we were on the last pip and refueled at 480 miles on the trip odo. Amazing fuel economy! The mileage across the entire trip was 49.5 mpg. Speeds were highway up to 72mph, tires were the OEM Bridgestone Turanza's set at 45f/43r psi (cold inflation pressure listed as 51psi on sidewall). Today we leave for Fayetteville, NC, about 540 miles each way. We now have about 1100 miles on the ODO. Love this car!