11.9 gallons

The Prius fuel gauge, like the gauge on almost all cars, is not linear. The Gen III Prius can use most of the 11.9 gallons, but don't expect it to work out to a nice even number per pip.

Tom

 

Don't get tied up in trying to know exactly how much as is in your tank, it will drive you crazy, you will be wrong and you might run out of gas.
Go with the computer and average each fill up against miles driven. If you live in the central area of LA and use the freeways 50mpg should be achievable. If you are in the Hollywood Hills or anywhere hilly you probably will not achieve 50 mpg.

 

Does the 2010 still have the "bladder" type like the gen II?

 

No, the 2010 doesn't have the "bladder." I've noticed that once the empty light starts flashing you still have another 50 miles or so left, I drove about 520 miles on a tank and filled up with about 10.2 gallons, so I probably could have hit 550, but as with any car it is not good to run it dry or that low. I use a combo of my avg mpg's for that tank (Trip A on my Prius) and the Miles to Empty reading. I figure once the MTE says "0" I have about 50 miles to find a gas station. Thoughts?

 

It appears that you haven't filled up yet. Until you have refilled a couple times, use the Trip MPG display and subtract 10 to 15% to get your approximate MPG.

The fuel gauge has 10 bars, not 8. There appears to be some consensus that the bars represent about 1 gallon each, on average, with about 2 gallons left after the "Miles to Empty" display reads 0. But don't expect good consistency from bar to bar, or car to car. Doing so may leave you stuck by the side of the road with an empty tank.

Until you have filled your own tank multiple times, you can't have a reasonable idea how your particular fuel gauge reads. The variation among my pre-hybrids was huge, and Toyota has done little to improve on fuel gauging precision.

 

You may want to read this thread on running out of gas.

Bob Wilson

 

A quick related question:

How does the tank estimated remaining distance gets calculated?

Am I correct thinking it is based on the last tank travel distance? Is it an average of the last few tanks?

(I went on a long trip (the car was new) with bikes on the roof (with 3-4 tanks). Since I came back home, I get a goofy estimated distance remaining as my MPG is a lot higher now that the bikes are off the roof.)

 

As most will tell you don't trust the gage! Unless you don't mind walking.

On a recent trip from OKC to Houston, I drove until I was at one pip left, in fact I drove about 15 miles on the last pip. I then stopped and put in 10.005 gals. On the trip back home the flashing pip started about 30 miles from home and no way was I going to try and out smart the gage. I filled up and it took 9.624. Seems like it should have taken more on a flashing pip than on the last stationary pip. On both fill ups I did not go past the first pump turn off.

I did notice on the trip home that on pip number eight I got 49.5 miles and on pip nine I got just under 20 miles before it started to flash.

So what I have learned and had made to realize is that normaly on 2 pips left, I get gas!

 

At our new owners clinic at the dealer, we were told to fill up when there are 2 bars left. Don't let your car run out of gas as we were told that it would have to be towed in and then something done to get it started again. It does have an 11.9 gal tank. We were also told that some gas has almost half ethanol and is very bad for these cars. The dealer has one right now they've had to drain and work on due to damage from poor gas quality. We were told Chevron, Shell and Texaco were currently the only recommended gas stations in our area of Texas. Also told regular is all that is needed, not premium.

 

I have run out of gas three times in our ZVW30:

1. June 1 - ran out of gas; 12.097 gallons to fill; 2.16 gallons on 'flash'; was on a downgrade at ~25 mph when "electric steering" fault light came on and turned into a parking lot at a park. Added 1 gallon and drove to gas station.
2. June 26 - ran out of gas; 12.16 gallons to fill; 2.18 gallons on 'flash'; was on a slight upgrade when "electric steering" fault light came on and discovered no EV mode. I had enough momentum and lack of traffic so I was able to coast to a parking lot and added 1 gallon.
3. July 5 - ran out of gas; 12.095 gallons to fill; 2.16 gallons on 'flash'; had turned onto a down-grade, access road when I noticed acceleration was weak and the traction battery level was falling. I proceeded to the bottom and on to the shoulder in EV mode with no error lights and drove down another 200 yards to clear the access road area. I added 1 gallon of gas and drove to the gas station.

I still do not like that the "check engine" light does not come on when the gas finally runs out. Worse, it silently goes into EV mode so the driver is soon running the traction battery down. This is followed by the wrong error code, "electric steering" fault and the car having no reserve, EV power. This denies the driver a chance to choose where to safely park. I understand the car is designed behave this way.

Bob Wilson

 

2007 Prius - I have noticed that I can add anywhere from 1 - 1.3 gallons of gas to the tank after the first shutoff. I usually get 150 - 165 miles before the first pip goes out when I do this. Otherwise the first pip goes out at 90 - 100 miles. On average, I get almost 52 MPG.

As to the question "How does the car calculate the miles to empty", I believe it uses gallons left in the tank times instantanious average MPG. You can therefore get a variation while driving, i.e. car reports 40 miles to empty one minute then 45 miles a few minutes later even thought you travelled an addtion 5 miles.

 

I don't think so. I've been on a trip with bikes on the roof (78 MPH on the highway, average of 36MPG) and the effect on this poor efficiency was apparent on the next tank of gas miles to empty, which was erroneous for the whole tank (it underestimated the remaining distance).

 

The 2004 - 2009 Prius used a bladder system inside the fuel tank to control emissions, the idea apparently being that if there is no air in the tank then there will be nothing for the fuel to evaporate into. Unfortunately, it would seem that this system made the fuel gauge somewhat unpredictable, with a few reports of people running out of fuel as soon as the last bar began showing. So it was recommended that people fill up with 2 bars remaining -- just to make sure.

Thankfully, this bladder system was abandoned in the 2010, so the fuel display now seems to be very predictable. My experience is that the car will stay on the top bar for about 75 miles or so after a fill up. Once most of the fuel has been used and the bottom bar begins flashing, it should be able to go up to 100 miles (although I wouldn't recommend pushing this to the edge ).

So, for the 2010, it would seem that once the bottom fuel bar starts flashing, you have plenty of time to fill up -- at your convenience. I don't bother filling up until well after the bottom bar begins flashing and the predicted distance to empty has passed zero.

 

2 Bars. Really? Why not 3 or four? Oh ,hell make it a half tank...just to be sure!!!

...it was recommended that people fill up with 2 bars remaining -- just to make sure...

 

I filled up today with one bar showing that had about 20 miles on it. It took 9.357 gallons.

 

The 2004 Prius design contained a lot of advanced technology in it, much of it unproven over the long term. Surprisingly, most of it worked reasonably well. However, the bladder fuel tank was not one of those better ideas. Not surprisingly, it didn't make the transition to the newer 2010 Prius.

 

i fully believe the DTE is purposefully designed to insure that there is plenty of fuel after it hits zero. i drove 65 miles past zero before and i am pretty sure i could have gone at least another 50.

the way i look at it. the gauge runs on an inverted curve. so if it takes 100 miles for the first bar to disappear, you have AT LEAST that much after you get to one bar. reason is, the top is probably not full, well the bottom is. so you will go farther on the last bar than you did on the first.

every Toyota i had before that had to old style analog gauges, the "add fuel" light always came on at 1/8th of a tank. as we all know, 1/8th is actually closer to 3/16th ...