Low Fuel Warning

[doctorbob]

Hi all,
I am a first time poster with a new, 2007 Prius. I was driving last night when suddenly there was an alarm in the cockpit and a "fuel vehicle now" warning showed on the display. I drove about 5 more highway miles and pulled into a gas station. I filled the tank to pump shut-off and it took 8 gallons (US). The specs on the car show a fuel tank capacity of 11.9 gallons. So, the alarm went off with the tank about 1/3 full and a range left of 150-200 miles. Previously, when I filled it with one "tic" left on the fuel gauge, it took 7.7 gallons. Is this normal or do I have a fuel-tank sensor that is out of whack?

[Proco]

<div class='quotetop'>QUOTE(doctorbob @ Apr 16 2007, 08:59 AM) [snapback]423918[/snapback]</div>

Hi all,
I am a first time poster with a new, 2007 Prius. I was driving last night when suddenly there was an alarm in the cockpit and a "fuel vehicle now" warning showed on the display. I drove about 5 more highway miles and pulled into a gas station. I filled the tank to pump shut-off and it took 8 gallons (US). The specs on the car show a fuel tank capacity of 11.9 gallons. So, the alarm went off with the tank about 1/3 full and a range left of 150-200 miles. Previously, when I filled it with one "tic" left on the fuel gauge, it took 7.7 gallons. Is this normal or do I have a fuel-tank sensor that is out of whack?[/b]

This is pretty normal. Do a search for the term "guess gauge" and you'll see tons of posts devoted to this.

Some posters will bemoan the fact that the Prius doesn't really have an 11.9 gallon tank (and some will go so far as to wonder if they could remove the bladder somehow). Others will give you a detailed breakdown of how the bladder works. Still others will tell you that you should always fill up at 2 pips and you're a fool to run to the low fuel warning.

But, yes, that is fairly normal.

[qbee42]

<div class='quotetop'>QUOTE(doctorbob @ Apr 16 2007, 08:59 AM) [snapback]423918[/snapback]</div>

Hi all,
I am a first time poster with a new, 2007 Prius. I was driving last night when suddenly there was an alarm in the cockpit and a "fuel vehicle now" warning showed on the display. I drove about 5 more highway miles and pulled into a gas station. I filled the tank to pump shut-off and it took 8 gallons (US). The specs on the car show a fuel tank capacity of 11.9 gallons. So, the alarm went off with the tank about 1/3 full and a range left of 150-200 miles. Previously, when I filled it with one "tic" left on the fuel gauge, it took 7.7 gallons. Is this normal or do I have a fuel-tank sensor that is out of whack?
[/b]

This is normal. Brace yourself for a whole bunch of replies telling you to search through the forum, but hopefully most people will be kind, considering that you are new to PC. This topic has been beaten to death, so there is all sorts of information lurking about. Search for "gas gauge", "guess gauge", "fuel tank", and "bladder".

In short, what you are seeing is completely normal in the U.S. version of the Prius. Our version of the Prius has a flexible bladder inside of the rigid fuel tank. The 11.9 gal rating is the gross capacity of the tank, not the usable volume. The bladder removes some of the usable space. The real kicker is that the amount of space used by the bladder varies depending on a number of variables, most notably temperature. Forget any notion you had about filling up based on the number of gallons, and instead focus on the gas gauge. If you insist on thinking in gallons, use a smaller number; something closer to nine.

Tom

[doctorbob]

Thanks to you both.
For the less patient, I did search prior posts before posting my question. My search for low fuel warning showed me a number of posts about the opposite problem-the car running out of gas very soon after the warning light went on. This made me wonder which situation was the "normal".
Thanks again.

[qbee42]

<div class='quotetop'>QUOTE(doctorbob @ Apr 16 2007, 09:59 AM) [snapback]423939[/snapback]</div>

Thanks to you both.
For the less patient, I did search prior posts before posting my question. My search for low fuel warning showed me a number of posts about the opposite problem-the car running out of gas very soon after the warning light went on. This made me wonder which situation was the "normal".
Thanks again.
[/b]

Searching PC is a bit of an art; the search feature isn't quite up to google standards. Sometimes I find myself searching for the OP's name when I know a post exists but just can't seem to find it. Finding a particular topic cold can be very frustrating.

By the way, welcome to PriusChat!

Tom

[Tideland Prius]

It is normal. Unfortunately, the bladder makes the tank size variable so when the car says "Add Fuel" do so ASAP otherwise the car will think it's out of fuel even though it really isn't.

[Darken]

I have to admit this has been one of the most confusing aspects of the car. You would think with the last blip flashing the car would take more then 8 gallons (with a rated 11.9 gallon tank)...but apparently not. Something dealers might want to tell their new prius owners about this...as it seem to come up alot and surprised me the first fill up...to the point I thought about sqeezing in more gas (a mistake many people might attempt to do)..

[rob_md]

I've been quite content to fill up as soon as the car beeps. My previous car, a 2002 Mecury Cougar, had fuel pump issues. They were prone to overheating if the tank got below 1/4 full. As one of the posters in the previous theads said, the fuel pump is cooled by the liquid fuel sloshing around in the tank.

So, I won't fight it.

[Tideland Prius]

<div class='quotetop'>QUOTE(Darken @ Apr 16 2007, 12:15 PM) [snapback]424150[/snapback]</div>

I have to admit this has been one of the most confusing aspects of the car. You would think with the last blip flashing the car would take more then 8 gallons (with a rated 11.9 gallon tank)...but apparently not. Something dealers might want to tell their new prius owners about this...as it seem to come up alot and surprised me the first fill up...to the point I thought about sqeezing in more gas (a mistake many people might attempt to do)..
[/b]

Indeed, although I have to wonder about all those "regular" folks that have no idea PC exists or simply don't join forums. How do they react and what are they thoughts on it.

[Prudence]

<div class='quotetop'>QUOTE(Tideland Prius @ Apr 16 2007, 06:48 PM) [snapback]424280[/snapback]</div>

Indeed, although I have to wonder about all those "regular" folks that have no idea PC exists or simply don't join forums. How do they react and what are they thoughts on it.
[/b]

Does that make the rest of us "irregular"? Hmmm...more fiber, I guess.