What is up with the Prius' gas gauge?

Mine doesn't work that way. Have you tried multiple gas stations & many pump nozzles and observed the same issue?

 

Two bars are way too much gas. You'll still have some gas left when it gets down to 0 mile.

 

Filling 7 gallons with 2 bars left sounds about right. If you're able to get more than that, something's wrong with your car

 

I don't understand what the problem is. This is normal behavior for any normal car.

 

Agreed !!

When the last pip blinks (the first time) ... you still have about 2+ gallons left.

Would you rather run out of gas ?

Generally speaking ... each pip is about a gallon, except for the first one, which is only lasts about 30-35 miles from what I've seen ... every pip after that is about 50 miles. If the 3rd to last pip just went out (meaning you have 2 remaining) ... I would put just under 8 gallons in my car. Since there are 10 pips total ... with 2 remaining, you should have about 350-370 miles on the tank .... probably shows about 80-100 remaining.

Any gas in the tank is constantly mixing ... it's not like the last two or three gallons stay in there forever if you don't run the tank down. Don't worry about it.

REV

 

On my 2012, I drive to about 420 miles and fill up, thats in the two bar range, I add anywhere from 8.5-9 gals. Soabout 47.5mpg. Old gas, not likely as it is blended as you drive and fill up. I know I can go another 100 miles based on those figures.

 

I don't even think about filling up until I get about 100 miles past when the last bar starts flashing and still have over a gallon left in the tank. The last fill-up was 10.218 gallons after going about 140 miles after that last bar starting flashing.

My advice is to pay attention to the displayed mpg and be aware of how much fuel you still have on board, understanding the fudge factor based on experience. The bars don't really mean much to me, especially after 8 years of experience with the current vehicle.

 

This morning, my remaining distance was about 70km and the last bar hasn't flashed. So our cars must be wildly different in order for you to go 160km after the last pip flashes!!!!

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My typical fill up is 8 gals. I have zero sympathy for people who run out of gas. Too busy, too distracted, "I thought I could make it," are just weak excuses to me. While AZGeek has it mastered, I don't advocate running to the last drop.

 

You'll still have some gas left when it gets down to 0 mile.

 

It's normal for our cars. I'm not sure i would drive 140 miles past the last pip blinking, that was a owner of a different model. I seem to have about 2+ gallons left when the last pip blinks.

 

You lost me, LOL.

But seriously, once you get familiar with the gas gauge's nuances, you can get closer to empty, if you like. But there's no benefit to getting too close. Personally, I'll fill up anytime the gauge is under half and my favourite brand is nearby.

 

once it passes "20" it usually jumps to "0", but I can still go for about 20 mi, and another 10 more after the warning beep, and still end up filling about 9.8 - 9.9 gallons
I realize it's not really a good idea to run on fumes, so I do try to fill as soon as I hit about "55"

 

Your 2004 is a different generation than OP's 2010 with a different tank structure, so it not relevant to this thread. And your gauge is reading longer than typical for your generation. We have had many reports of Gen2 drivers stranded at shorter distances. I seem to remember Jimbo running dry just 7 miles after the flashing pip, and someone else running dry without the pip ever flashing.

The reference point for Gen3 is Bob Wilson's thread: [WARNING] Running out of gas (Gen III). While intentionally running dry, he went 122 and 132 miles after the flashing pip, while getting better mileage (56 and 60 mpg) than many drivers here on PC. That amount of fuel on the flashing pip seems to be typical of other Gen3 drivers who have reported here.

But remember that gauges vary. Some will go longer, but others shorter. And Bob did his tests on an already warm engine on flat roads in good weather. The very same car, with a different driver running ten mile commutes on hills and having to re-warm the engine multiple times in winter, will run dry much shorter than that.

My old nonhybrid, with a claimed gas tank size a hair under 16 gallons, takes only 9-10 gallons when its gauge reads its analog equivalent of 2 bars.

The two cars before that, were proportionate to this Prius. My 'most accurate' gas gauge was in my very first car, and its gauge was almost dead on. Key word: Almost. Its small error was in the wrong direction, and did run dry with the needle slightly above E. This happened on its very first tank, just after my parents had trained me that their cars had plenty of gas to get home after the needle drops below E.

 

There is a "miles to empty" estimate on your trip meter - what does it say at 2 bars? I'll bet it reads somewhere between 60 and 100 miles. Think about it; the tank holds 11.9 gallons. Multiply that by your average mpg, what do you get? What's your typical miles at 2 bars? You still have a lot of miles left at 2 bars.

 

Let me re-post my "gallons per pip" chart:

 

Good point. However, I'm certain I will follow the same behavior once I am comfortable with the operation of the fuel system on the 2012. Or, I could become one of those "prepare for the end of the world" folks and top off at every possible occasion so I can rule the post-apocalyptic world.

 

I also run mine quite low on occasion, in order to test out the fuel range before it is really needed. This relates to past experience with long road segments without fuel, and stations shut down for nights and holidays, and the only open station adding a large holiday or tourist trap surcharge. It is clear that many folks in this forum don't have similar experiences.

But I predict that you won't be able to uniformly get 140 miles past the flashing pip on your 2012. That sounds more like a Gen2 fuel sensor badly out of calibration.

 

I did a little experiment with this too. Warning beep usually starts between 20-30 miles left. At this level with one bar left, it can prematurely engage the beep and flashing one bar when you are going uphill, going downhill and when making turns at a higher speed rate. Funny thing is that when I stopped at my driveway, computer says I have 14 miles left in my tank. Turned car off and went inside the house to get something and came back to go fill the prius gas tank. When I started the car, computer say 0 miles left. Still was able to get to the gas station that was less than a mile away with no problem. Have my 5th fill up with only 9 plus gallons each fill up. In the last 4 fill ups, I got a total of 2018 miles on my ODO and based on my odometer reading, I'm getting over 50mpg. Got my new prius with only 6 miles on it. My cons is showing 53 or 52 mpg. Looks to be pretty close to me.

 

At zero miles left to empty, my Gen III takes about 9.6 gallons to fill. With an 11.9 gallon tank, you can drive quite a distance but I don't like to cut it too close, so I fill up 20-30 miles later.