Gas Gauge accuracy

I find it very accuarate...on my first fill up when the last bar started blinking, I went another 30 miles....fill up was 8.9 gallons...so only .6 gallons left in tank...With that .6 gallon left I probably had another 20 or so miles basesd on my 54.8 MPG actual for that tank.

Update!! Second Fill up today. 531.5 miles on tank...9.3 gal fill up...57.1 MPG. I would say guage is very accurate!

-M

 

I did a little simple math last time I filled up to try to figure out the notch-to-gallon ratio of the gas gauge and it worked out like this :

9.5 gallon tank / 10 notches in gauge = 0.95 gallons per notch

When I filled up my tank last Sunday, I had 2 notches left and the car took 7.541 gallons.

7.541 gallons / 0.95 = 8 notches (7.93 rounded up) (plus the 2 that were left = 10 notches)

Pretty darn close!

 

I know for a fact that on our 2010 Prius when
I fill up, note: I can't do this in Oregon because it
is forbidden to pump you own gas, but when in
Washington I noticed that after the first auto click
off on the pump at slow speed I can still nurse in
another 2 gallons of gas untill I can see standing
gas at the filler neck.

I bet the same is probably true on the Prius C, maybe
not two gallons but maybe 1 or 1 1/2 gallons after
the first auto click off to the top of the filler neck.

I know there are memebers here that will gringe because
of filling in this method but this is exactly what
Wayne Gerdes did when testing the Prius C for
Cleanmpg.com.

 

I had that problem a lot with my 04 Prius, I never really knew how much gas was in my tank and sometimes I would fill up and the gauge would only show it 3/4 full. That's one of the reasons why I traded that in for my C.

 

I really don't have that problem as I always fill when about 1/2 a tank shows. But the 07 and the 1 fill on the Prius c seem to be about what the tank indicator shows.

 

Major problem with gas gauge not being accurate
We had 2 bars showing and got the warning sign "Hybrid system not working pull over immediately". The cruising range was at least 20. It had run out of gas. 10 days later it ran out of gas again and the cruising range over 30 and just had gone down to 2 bars. Gauge replaced. I still don't think it is working accurately

 

I'm terribly sorry that's happened to you, and I greatly hope it gets sorted out quickly. But do you really need to post it over and over in every thread about the gas gauge?

 

I am having this same issue... how long did it take for them to replace the gas gauge for you?

 

I am having this issue as well where it will run out of gas when there are 3 bars. Did anyone else file a defect report on nhtsa.gov to log this issue?

 

For those having the gas gauge issues I'm curious as to what the "cruising range" in your drive information screen shows when you run out of gas so early. I.e., is the problem JUST with the pips showing on the "gas gauge" or does the error run throughout the system? Knowing this might help others determine if they have a problem early on if one screen is inaccurate and another is accurate.....

 

So I took my car in to Toyota and they had it overnight... they didn't find anything wrong!? I don't get it. This is really frustrating

 

I guess at the point where they are trying to tell you nothing is going on, I would:
1. Ask what the cruising range SHOULD be at 1 and 2 bars - and when you should run out of gas. Then you have THAT documented.
2. Keep a camera or smart phone handy in the car so that if you have the problem AGAIN, you can take a photo of all your different screens to demonstrate to them what was showing at the time it happened.

How frustrating for you!!!

 

Not quite sure what to make of mine. It used to be right on the money - now when I fill up the top bar doesn't usually light and on the last fill up I was down to the half way point, but this time the car accepted 22.23 litres (61.75% of capacity). Last time it accepted a similar amount I was an extra bar further down.

 

So....it's the Gas Guess instead of the Gas Gauge! (sorry, couldn't help myself )

 

I have an issue with my gas gauge too. The cruising range it states is pretty accurate, but the number of bars is not even close. The when I get to the bottom 4 bars, I need gas within 100 miles. I drove 800 miles the first day after buying my car and the first 250 miles of wach tank used almost exactly half the tank. The last 100 miles used the final half.

 

That sounds exactly how floats in tanks work. The resolution at the top and bottom of the capacity are not linear. Please check out the HowStuffWorks site, it's really very simple with their video showing the correlation.

Also, the Prius C does not have a bladder tank like the earlier liftback Prii. It has a normal tank with a fixed volume. Don't get creative and think you can cram in another 2 gallons after the auto-shutoff has clicked, unless you really enjoy spilling gasoline all over the ground and your car.

Everyone should be using their trip odometer as a rational backup for tank capacity. Those of you that ride motorcycles are accustomed to doing this to estimate remaining range. Chances are if you average 50 MPG that after 400 miles, there's only 1.5 gallons left and it's a smart idea to fuel up.

 

This time I had 4/10 bars on the fuel display and the car took 21.33 litres (59.25% of capacity). I filled to the second click of the auto shut-off at which point I could see some fuel splashing back without spilling, but the guage once again only showed 9/10 bars.

The plot thickens.

This time I'm trying our Premium Unleaded 95 (US Octane ~90) instead of our Regular Unleaded 91 (US Octane ~86).

 

Only filled my car up a few times. First fill up was on the dealer filled tank on my way to Vegas. Kept my eye on the cruise range and it sat at 1 mile for almost 20 miles and the 1 bar started flashing. I stopped at the next exit to fill up. Took 9 gallons to fill! I filled up on the slowest notch and was shocked at how little gas was left in the tank. On my next fill up when the one bar started flashing I was about 30 miles away from the next gas station. I filled up again on the slowest setting and it only took 7.8 gallons? I'm having doubts about the gas gauge. Still have half a tank before fill up and hopefully I can start to get some consistent numbers.

 

I don't think the C has a conventional fuel tank, it has a bladder fuel tank that can expand or contract due to weather mostly. Something about being more environmentally friendly. This is what the gen2 had as well. I would just trust the fuel gauge.