I just bought a 2009 Prius
I just bought a 2009 Prius and am having the same problem. Only filled it up twice, first time took 7.6 gal, second time 7.1 gal. I'm not happy about this at all. The service dept of my dealership was clueless about it (or pretending to be in ordered to sweep it under the rug). This is very bad engineering. Surprising considering how well the rest of the car was thought out.
By the way, for those of you who are trying to ascertain your MPG on a tank of fuel from the multi-function display - you're wasting your time. The MFD is only a computer estimation. The ONLY accurate way to calculate MPG is by dividing the total number of miles driven on a tank of gas by the number of gallons to fill it back up.
Actually, the MPG reading on
Actually, the MPG reading on the multi-function display should be fairly accurate.
Fuel delivery in the Prius (and every other fuel injection engine) is computer controlled.
And the computer knows exactly how much fuel it is delivering to the engine.
The largest "variable" for MPG inaccuracy is the odometer that keeps track of mileage driven. If your odometer is reading accurately (depending on tires, load, inflation) then your MPG reading should be accurate.
If you want to keep track of fuel consumption at the pump, you have to AVERAGE many tanks full of fuel. Because the "shut off" point when you fill the tank can vary by over 2 gallons from one fill up to the next. (your Prius consumes 7.3 gallons, but you put anywhere from 5.5 to 9.5 gallons in the tank when you fill it).
I bought a used 2004 Prius
I bought a used 2004 Prius about 2 months ago and love it. Im on my 6th tank. Each tank I have run past the flashing 1 bar about 20-30 miles. Each filling I fill slowly and go to two clicks on the pump. It has taken between 9.8-10.4 gallons. I was averaging about 53.5 mpg so I was getting about 500-540 miles per tank. Now that I am getting the hang of pulse and glide I am showing 64 mpg and am already over 450 miles with 3 bars remaining. I expect to go to 650 miles on this tank. For me the bladder tank is working great. accurate fuel flow sensors and bladder tanks - airplane technology!
I have a little contact with
I have a little contact with the aviation industry. Aviation fuel bladders are designed to remain soft and flexable at -50 degrees.
Toyota just got cheap on the fuel bladders. These are NOT aviation quality by any stretch of the imagination.
My wife has an '06 with 49K
My wife has an '06 with 49K miles. She drives 120 miles roundtrip to work 2-4 times a week. Even with my occassionally driving we consistently show 46-48.2 mpg on the screen. Historically gas added at fill-up seems to match mileage driven at that mpg.
For 2 years everything was fine including going thru 2 Houston winters (not real cold). No problems with gauge reading or fill volume.
2 weeks ago when we were down to 3 PIPs it only took about 5.5 gal (about 1 less than expected) but gauge showed full when filling finished. Since then the gauge drops very fast (to 2-3 PIPs in 250 miles vs about 375 before) and can only refill with about 5.5 gal. - this suggests that we're getting about 47mpg and the tank's capacity has shrunk. No change in driving habits or in average mpg on display. Have given the filler a 10 second rest and then started again with only a few cents additional going in so I'm sure it's full. Temperature here recently has been between 45 and 80, fillups have generally been when it's been over 55.
After 3 refills with the same behavior, we took the car to a local dealer today and they reported no problem on computer diagnositics. We have an extended warranty that should cover tank or sensor problems, but the dealer says they can't find anything to fix.
We will try filling when gauge gets to half a couple times and see if there's any improvement.
Hope the following info
Hope the following info helps out on a number of the problems reported above:
After reading the info outlined below I filled the tank (it just dropped from 5 to 4PIPs) - was able to put in 5.5 gal which seems about right. We'll see what happens.
Did some digging on the web & found this link that gives tech info about the fuel system:
http://www.autoshop101.com/forms/Hybrid13.pdf not sure who's it is or accurancy of info - but makes for interesting reading.
I wonder if our dealer reset the inclinometer (see page 2 on above link) "The inclinometer must be reset if the customer complains that they can only pump a few gallons...or they run out of gas with three or four bars left..." and magically it corrected. Hmmmm...
Other info I gleaned from the link:
1. Don't top off (over fill)
2. Make sure you have good seal between the filler nozzle and filler neck - pressure will ensure bladder is fully expanded. Perhaps filling at full speed will help the pressure.
3. "Do not use premium gasoline. It may cause starting problems..."
Best of luck to all!
I think this problem is much
I think this problem is much more serious than most who have posted on this page. It is only a matter of time before someone is killed by this design defect. Either by the car stopping in traffic and causing a serious accident, or by someone walking from the car to get more fuel.
I have owned my new 2008 Prius for 4 months. When the weather changed in the past month, temperature dropping to the freezing point, I have noticed the following:
1 - I have run out of gas two times
2 - The amount of gas that goes into the vehicle is much less than manufacturer specifications
3 - The low gas warning light that per specification should be 3 gallons is under a gallon
The fuel display is grossly inacurate and there is no reliable way to know how much fuel is in the Prius nor how many miles you have before needing to refuel. If you want to refill your car at random intervals, then this is the car for you. If you expect a car that has reliable mileage and capacities, this is not a good car to own.
I ran out of gas today when I thought I had at least another 100 miles to go before empty based on history and previous mileage estimates. Same thing happened a couple of weeks ago but it was easier to get gas. Today I was stranded literally in the middle of no where. This seems to be a serious design flaw.
I plan on presenting this to the dealer tomorrow and asking for a refund. I cannot drive a car that I have no confidence in fuel consumption. I regularly got 600 miles to the tank during warm months, and have run out of gas at 450 miles on two occasions. Take all the variations in gas stations you want, but no car should have 25% variations in fuel consumption or capacity.
It is only a matter of time before somebody dies because of this fundamental defect. I will start with the dealer to get a refund then continue with the NTSB and state lemon laws to get my money back.
Although I love the car, Toyota has created a safety hazard unless you are willing to refill at unpredictable intervals.
I just leased a 2009 Prius 2
I just leased a 2009 Prius 2 Fridays ago. When they gave me the car it was full, after a little over 200 miles I was down to 1 bar so I had to fill up the tank for the first time. I was astounded that the tank only took 7 gallons. So... I started to investigate the actual tank size of the car which led me to this blog. I am totally DISGUSTED! I traded in a 2006 Civic hybrid for this prius and now I want my old car back in the worst way. I am one of those numbskulls that runs the gas down until the light comes on then I fill up. I know it is bad but it is my bad habit! However, I swear to all that is holy the first time I run out of gas with 2 "bars" on my gas gauge I am going postal on the dealership.
Seriously, I don't know that laws in MD but do I still have any chance at returning the car?? I really investigated the Prius and I never encountered anything about this gas tank issue and I am terrified about running out of gas late at night or something. This blows!