Fuel gauge

This is a known "feature" of the gauge. Usually 3 gallons is enough to reset the fuel gauge, but that's usually the threshold. Try 4 gallons and it should be fine. Additionally if you now fill the tank the fuel gauge should "reset" and read correctly.

 

While the Guess Guage will take some time to figure out, the one thing you really do not want to do is just drop a little gas into it. FILL IT UP!!! The fuel calibraton system will thank you!
While there are many schools of thought as to when to fill, 2 stand out, when it's flashing or at 2 Pips.
Personally I'm a 2 pipper person, but hey, that's just me. I usually put in 7.8 to 8.4 gal, get 400 miles and am a happy camper.
Just don't run out of gas, That's BAAAAD Egon!!

 

Yes, you can take less than 3 gallons each time, and NEVER show above empty.

(This is hidden on Page 122 of the 2007 manual)

 

To keep the guess gauge somewhat close to accurate, always fill the tank to it's first "click off". So, basically fill it up. I always do because one time I did a partial fill like you and the results were screwy.

 

Welcome to PC!!

Let me save you alot of trouble. There's one very strange thing with the GenII prius and thats its very strict gas vapor recovery system in the fuel tank. It does all kinds of weirdness to meet its ZERO Emissions mission. The fuel fill up is a pain but here's how to fix it or at least deal with it:

Swanny's right. Never ever try to top it off or continue clicking fuel into like every other car you have ever owned. If you continue that procedure you will be rewarded will gasoline in your loafers.
Here's the tip.

You have to let the gas tank vent for 30 seconds or so.

It will not hiss like alot of other cars when you take the gas cap off. It will degas over a period of time.

When you pull up to the gas pump get out and remove the cap.
Stow the cap in the cover holder. Go inside the station and buy a drink. By the time you come out the tank will have vented.
You will then be able to get at least 8 gallons into it.
Pump it in very slow and hang up the pump on the first click.

Drive on that fill up till the gauge shows 2 pips. Thats approx 350 to 370 miles. 370 miles is BINGO.

Been using this procedure for over 2 years with never ever a problem. I have never ran out of gas and only had one gas belching episode until I figured it out. Please try it. In fact go back to that exact gas pump you experienced a probelem with and try my method and report back please.

Its one of the little weird things the Prius does to meet its emissions. In order for the car to do that it requires your participation. Its not a big deal.

 

Well, I used to be a blinking pip guy, but for a couple of reasons when I ran out of gas and the second time stranded because I pushed the Start button too many times before adding the required 3 gallons of gas, I have become a 1 pipper. That seems to be a good compromise.

Also, many times what I would do is have a 5 gallon can at home and put it in when it started to blink. That way I don't have to stop at the gas station as often, and I don't have to haul around the extra gasoline in a full tank.

And DO NOT overfill the tank. There are potentially serious problems with that. You can somewhat calculate based on the miles driven on the MFD, so that if you're putting in over 8 gallons at 400 miles it is probably just about filled and you should be paying attention for a bad gas station nozzle that won't shut off.

 

When your Prius clicks off prematurely or then won't click off at all its not a bad gas nozzle. See my post above.

 

I've only filled up twice, but the second time, it did hiss. The first time, it didn't, which surprised me at the time... I was actually kind of relieved when it did the second time. Should I be concerned instead?

 

Mine hiss'es once in a while but for the most part will not hiss like alot of other cars. My point was I guess is not to expect a hiss to confirm what I was recommending. It takes a while for the tank bladder to loosen up and vent to release all its trapped air especially if its in the winter. But since I began letting it vent it has behaved perfectly.

If you pull up to the pump, get out and just shove the pump in, it will be very cranky and continue to click off. You may be unable to get hardly any gas in it at all.

I re-fill at 2 or 1 pips. I open the cap, let it vent for a minute or 2
with no pump in the fill hole. Just open.

Pump 87 octane on slowest possible setting. It will take approx. 8 gallons. The very first time it clicks off on slow fill hang up the pump. Do not continue clicking. Drama over.