When is it really "empty"?

[orracle]

I am on my 4th tank of gas on my '05 Prius I bought used and I haven't felt this way about a car since my '69 Mustang in college.

I am amazed at how quickly it starts to bug you to refill. The first time I went to the station I had over 3 gallons left! The second time, two, and the last time almost 2.

I know you don't want to run out, but jeez, is the extra early warning really necessary? What do the rest of you do? Just go by the mileage and ignore the reminders??

[Marlin]

How do you know how much gas you had left? The Prius doesn't actually have a usable capacity of 11.9 gallons. If you assume that it does and try to use the mileage to out-think the gas guage, then you will likely end up hiking to a gas station when you run out of gas.

There are many, many, many posts on PriusChat from people who tried to out-think the gas guage and ran out of gas. They all follow the theme of "I've been averaging 45 miles per gallon and after driving 480 miles, I ran out of gas, even though I should have had 55 more miles to go on a 11.9 gallon tank!". They then usually admit to seeing the gas guage blinking 50 miles earlier but chose to ignore it because they knew better.

Do a search on "out of gas" for more info.

I personally fill the tank when I get down to 2 pips on the guage. That usually equals 8.5 to 9 gallons of gas.

[orracle]

I did use the 11.9 as a gauge, adding to that what I put in it. But based on another forum elsewhere this was a hot topic and they suggested using mileage as a better indicator, starting with 400 in winter and 450 in summer. My last tank went 539 miles at 54 mpg so I think I'll stick with 500 miles or so.


<div class='quotetop'>QUOTE(Marlin @ May 24 2007, 11:01 AM) [snapback]449092[/snapback]</div>

How do you know how much gas you had left? The Prius doesn't actually have a usable capacity of 11.9 gallons. If you assume that it does and try to use the mileage to out-think the gas guage, then you will likely end up hiking to a gas station when you run out of gas.

There are many, many, many posts on PriusChat from people who tried to out-think the gas guage and ran out of gas. Do a search on "out of gas" for more info.

I personally fill the tank when I get down to 2 pips on the guage. That usually equals 8.5 to 9 gallons of gas.
[/b]

[Tideland Prius]

when is it really "empty"? - Neva!!! haha..


Seriously though, if the computer thinks it's empty, the car will shut down so when it says "Add Fuel" then just do it even if there really is (and I have no doubt) 3 gallons of fuel left.

The TCH, HiHy and RXh have pressurised gas tanks (or so it seems? I think Evan or Danman can give a more detailed respoosne) so it eliminates the need for the bladder.

[bwilson4web]

<div class='quotetop'>QUOTE(N_IL_Priusfan @ May 24 2007, 10:48 AM) [snapback]449074[/snapback]</div>

I am on my 4th tank of gas on my '05 Prius I bought used and I haven't felt this way about a car since my '69 Mustang in college.

I am amazed at how quickly it starts to bug you to refill. The first time I went to the station I had over 3 gallons left! The second time, two, and the last time almost 2.

I know you don't want to run out, but jeez, is the extra early warning really necessary? What do the rest of you do? Just go by the mileage and ignore the reminders??
[/b]

I have a little, 1 gallon spare can I carry in the trunk of my NHW11, 2003 Prius. When the car runs out, I drive on to a safe area and add the extra gallon. Then I have about 70 miles to find a gasoline station. Crude, it is effective.

Bob Wilson

[kdmorse]

Two comments:

1) If you pump in 8 gallons and it clicks off, that does *not* mean you're now full, and there were three gallons in there. It often just means the pump clicked off before the tank is truly full. When the pump clicks off, I can easily add 1.5 more gallons every time. Additionally, capacity varies with temperature, and 11.9 is not a good constant.

2) My 2006 consistently says "Add Fuel" and starts blinking when there is 0.9 gallons of fuel left. Your results may vary, these results good for my car, my fuel gauge, and my location only.

Regards,

-Ken

[tochatihu]

Prius fuel tank has a flexible polymer liner. This may interfere with our efforts to get a full fuel load. Over time, my 2001 Prius has been accepting smaller fillups, even though I often drive until the "get fuel now, idiot" message is presented. Usta be 11.4 gallons, now anything over 10 is a big deal. But whaddayagonnado?

Running out is not to your advantage, so please don't do that unless you've something to prove.

[wyounger]

<div class='quotetop'>QUOTE(kdmorse @ May 24 2007, 03:16 PM) [snapback]449261[/snapback]</div>

Two comments:

1) If you pump in 8 gallons and it clicks off, that does *not* mean you're now full, and there were three gallons in there. It often just means the pump clicked off before the tank is truly full. When the pump clicks off, I can easily add 1.5 more gallons every time. Additionally, capacity varies with temperature, and 11.9 is not a good constant.

2) My 2006 consistently says "Add Fuel" and starts blinking when there is 0.9 gallons of fuel left. Your results may vary, these results good for my car, my fuel gauge, and my location only.

Regards,

-Ken
[/b]

Ken's quite right. I tried the logic stated in #1 and promptly ran out of gas 45 miles after the pip started blinking and it said "Add Fuel".

I think the gauge probably works pretty well. What's inconsistent is how much gas the thing wants to accept. Now that I've had a few tanks in warm weather it seems to be getting more consistent and less fussy about filling in general (less premature shutting off of the pump, less of the car not getting along with a particular pump, and less trouble getting back to truly full). Now after a fill-up I pretty consistently get 140 miles (@46 mpg) before the gauge comes off of reading Full. This is my first summer so we'll see if that starts dropping when the weather gets cold again and the bladder starts getting stiffer.

[FireEngineer]

Over 50F use the MFD MPG times 10, when you reach that number of miles time to refill. Under 50F use times 9, bladder shrinkage.

Wayne

[NoVaSnow]

<div class='quotetop'>QUOTE(Marlin @ May 24 2007, 12:01 PM) [snapback]449092[/snapback]</div>

How do you know how much gas you had left? The Prius doesn't actually have a usable capacity of 11.9 gallons. If you assume that it does and try to use the mileage to out-think the gas guage, then you will likely end up hiking to a gas station when you run out of gas.

There are many, many, many posts on PriusChat from people who tried to out-think the gas guage and ran out of gas. They all follow the theme of "I've been averaging 45 miles per gallon and after driving 480 miles, I ran out of gas, even though I should have had 55 more miles to go on a 11.9 gallon tank!". They then usually admit to seeing the gas guage blinking 50 miles earlier but chose to ignore it because they knew better.

Do a search on "out of gas" for more info.

I personally fill the tank when I get down to 2 pips on the guage. That usually equals 8.5 to 9 gallons of gas.
[/b]

This is exactly my experience. After 34 fillups, I have averaged 420 miles of driving between fillups. I have added an average of 8.7 gallons each time. Most fillups have occurred at 2 pips, maybe 5 or 6 at 1 pip, and about 3 at blinking pip.

Yesterday, I filled up at exactly 420 miles. I only put in 7.8 gallons, resulting in my best tank ever at 54 mpg.

I know I could go more miles on a tank (my personal best is 502), but why push it?