Prius gas gauge

All PIPs are not created equal. Here's the data for the 2010:

View attachment 30952

I got the liter info from the repair manual, then did the conversion to gallons. The data is for when the PIPs normally come ON, so I won't say for certain if the ranges hold for when the PIPs go OFF.

 

RRxing, nice chart, but I have just decided to get gas when I find a good price for gas and I'm down to 2 or 3 "pips"... It's a pleasant supprise to "only" buy 7 - 9 gallons of gas!!! Especially since prices in Chicago area have been so High last few months...

 

I agree. There's no real reason to flirt with running out of gas. I usually fill up at around 2-3 pips as well. As far as I'm concerned, the DTE is just a gimmick (and not just on the Prius, but all cars.)

 

New 2008 owner here I am learning. Ran out of gas on the first tank I full. I was trying to get back to my town before I filled up, dumb idea. Drove 487 miles on probably 10 gallons, the display said I was averaging 48 miles per gallon so it was right. The PIP started blinking at 420 miles and one square showing. I thought since it holds 11.9 I theoretically should be able to go at least 135 miles and I was only 80 from home when it started blinking I read somewhere it starts blinking with 3 gallons left. I also read DON'T over fill it so when I filled it for this trip I only put in 1/3 of a gallon after the nozzle shut off, a total of 9.1 gallons. I have concluded if you stop putting gas in when the nozzle stops (and that is what you want to do so the bladder and canister isn't damaged) you probably only have 10 gallons in the 11.9 gallon tank. Therefore "I state my name do solemnly swear to put gas in my wonderful Prius AS SOON AS THE LIGHT STARTS BLINKING" and not try to go another 67 miles.

 

I think one pip per gallon is fairly accurate, 11.9 gallon tank with about 1.9 gallons not accessible means there is only 10 usable gallons in a full tank, 10 pips, do the math, so when that last pip starts blinking you are into that 1.9 gallons that doesn't seem to really be able to get pumped out, get gas fast, or here is how I do it:

When the second to last pip disappears and I'm down to my last pips I add gas in about 35-40 miles in nice weather or 25-30 in this weather, just to be safe.

I've been doing this for 7 years in 2 different prius and never run out of gas once, I think people adding gas when there's still 3 or 4 pips left are doing the environment a disservice for the following 2 reasons:
first, the very act of adding gas releases toxic vapors into the atmosphere, so adding gas 52 times a year is worse for the environment than adding gas 36 times a year even if its the same total gallons yield.
second, your best fuel economy comes at the end of the tank as your car gets lighter and lighter your FE goes up.

I certainly don't want to encourage anyone to play the Seinfeld 'how far will it go?' game as running out of gas is not good for our Prius.

 

Just to let everyone know, I once ran completely out of gas and I still showed two pips on the gauge. I now fill up as soon as it hits two pips (but that's just my paranoia)

 

I'm on my first full tank with my new-to-me used 2010 Prius II. I have 556 miles as of this morning. So I'm averaging 53.1mpg, at 38mph. the last bar has been blinking for over 40 miles. since the car is brand new and I didn't know what the flashing bar meant, I was waiting for it to disappear before i got gas. I was completely unworried on my 36 mile commute this morning. now i'm trying to make up for all the sweating, stressing, and worrying i should've been doing this morning. i even asked myself "are you crazy?!?" haha. if i only knew how some prius chat members had run out of gas long before the point i am currently in. the nearest fuel is 2 miles away, and I have a full battery, so if worst comes to worst and i dont make it all the way, i'm hoping i can limp there in battery mode? not sure, but when i get to the gas station (hopefully) i'll take a pic of the screen and post it here. I love my prius!!

 

Your Gen 3 gauge is more forgiving than the Gen 2's in this discussion.

 

Generally not a good idea to let the fuel level reach empty because the fuel pump is cooled by the fuel!

The fuel gauge on the Gen II Prius is inaccurate because the internal bladder is not very flexible when cold.

After the hottest summer day fill up, my 05 will go up to 160 miles on the first pip.

After the coldest winter day fill up, I will be lucky to get 10 miles on the first pip.

When it's really cold out - below 0° F - the gauge doesn't even make it to 10 pips after the fill up.

That tells me there is up to a 3 gallon difference in capacity when the temperature is 0°F or 90°F.

That's one reason the bladder was not included in the Gen III despite Toyota's claim that the difference wouldn't be more than a gallon between extreme cold and heat.

 

The Gen 3 doesn't have a problem with the gauge. While DTE is unreliable, it's typically a bit over 9.5 gallons and has never been 10 gallons. The tank is 11.9 gallons so there's plenty of wiggle room.

My commute is 41.4 miles round trip and the city I work in has gas 10c more expensive than my home city. So, unless I'm going to be driving much farther I wait until 1 pip flashing (about DTE 20) and then fill up close to home in my city on my way home from work or on my way to work. Either way it's a diversion of just a few hundred feet so no big deal.

 

With 'only' 40 miles of blinking, and most of that on a single trip, odds of a Gen3 making it 2 more miles to the station are strongly in your favor. But if it doesn't, be very cautious with the battery. It can't go 2 miles, and it won't give you any additional warning before it just quits, as happened to Bob Wilson in [WARNING] Running out of gas (Gen III). I believe the Gen2 is a bit more informative when running out fuel than is the Gen3.

If the engine won't run when it should, watch the SOC (battery level) gauge like a hawk, and if it falls to 2 bars, park it right now and walk or call for help.

 

For around the last 4 months, I've been filling up with only 1 or 2 pips and it's only taking around 5 or 6 gallons... think my cruising range is less than 330 miles. Something has definitely changed as the car has aged, or else there is a mechanical problem or the gauge needs calibration. Does the bladder shrink as it gets older, like in people? ;-) It could be a combination of winter (lows in the hi 20's or 30's and highs in the high 40's and 50's) and an aging bladder, I don't know. Any ideas what would cause diminished fuel capacity or inaccurate gauge reading?

 

Same question here out of curiosity. Bought an 09 with 36k 5 weeks ago and have put on ~1800 miles. I have filled up a few times so far, typically at 2 pips and get 330 miles to such a tank. weather has been cold for me as well. my guess based on reading the threads and my experience is that in the cold it's more like .75 per pip.
curious what others experience?

 

I fill mine at 2 pips, put in 8 gal, get 400 miles for my efforts, slightly less in winter. There is really no excuse for ever running out of gas.....

 

i meant to point out that at 2 pips i'm only able to fill woth 6.5 gallons and get 330 miles averaging about 50mpg. Based on my rough math that leads me to conclude that at least in the winter time, for me, each pip is .75 gallons not 1 gal.

 

When you're trying to understand the inherent inaccuracies of the
combination of the Gen II Prius' "guess gauge" and fuel tank bladder,
it helps to have solid information about the system.

It hasn't yet been posted in this thread, so here's how to see it.
Go to this Toyota technical site and click on Technical Articles, then
the Hybrid13: Fuel and EVAP System link.

I think that what you'll see/read will prove to be both revealing and
surprising in it's complexity.

 

I'm stilllearning how to intepret my gas gauge. In previous vehicles I have learned at what mileage to expect from a tank basked on the total amount that is there based then on total mileage traveled no matter what the gauge says. On long trips I know my 4runner gets anywhere from 20-24 mpg. When the gauge gets to 1/4 I get gas. Figure the mileage and it comes out 300 miles traveled, 12.8 gallons = 23.4 mpg. So using basic math skills if my monitor tells me that after 310 miles averaging 47 mpg, I fill up the car and it only takes 6.3 gallons it tells me thats 49 mpg. I should be able to get with an 11.9 gallon tank even at the reported mpg of 47 I should be able to safely go around 500 miles with around one gallon of fuel left to get to a station safely, but my gaugue tells me, 1-2 pips, and only using around 6-7 gallons, this really confuses me. Maybe I need to take a one gallon fuel can with me just incase and try to see how far I can go for real, till it does the "GET GAS NOW" indication comes up! LOL

 

Unless you take the effort to fill the tank to the neck of the filler tube every time, you're not going to get anywhere near 11.9 gallons in there. Probably closer to 9-10 gallons with letting the pump fill to automatic cutoff. I usually fill when I hit 10 gallons used; which is anywhere around 550-600 miles. The "Get Gas Now" message typically appears when I've got 1.5 gallons left until empty.

 

I always fill at the halfway point--or close to it. And I go by the electronic mpg, which is more accurate than calculating because of bladder changes.

My wife has an Insight with a regular analog gas gauge. She'd go nuts with the Prius digital gauge, as she usually goes to a quarter tank before adding gas--and often doesn't fill the tank.
A mechanic at a local garage told me the Insight is one of the best cars on the market--a well-kept secret. She has 28K miles now in 2 years--no problems. Sorry for the digression.