1 mile left

I have no clue what this is about. I have a Gen 3 with out Nav.

 

I have done at least 40 after it hit zero. I was on a road trip and thought there would be a gas station ahead since I passed one. Then 20 miles in I didn't see a gas station and the navi said at least another 40 more miles. I turned back around, I was worried I wasn't going make it. But, I thought I read there are close to 2 gallons in reserve?

 

The most I ever drove after DTE @ 0 was an additional 81.7 miles. I got 64.6 mpg for that tank.
I had 1.064 gallons of gas left. When I get gas I never top off and stop filling at the first click.

 

Keep in mind that the "miles left till empty" is really how far you can drive before you really need to fill up for the health of the car, not that the tank is physically empty.

Driving with the tank that low is really bad for the fuel pump and unless its an emergency and you have no choice it's not a good idea to run the car in that state. This is especially true in older vehicles where there's likely to be more sediment and crud in the fuel tank.

 

I have a 2010. I just recently drove definitly 20 miles and faily sure 30 miles when the DTE was at "0".

 

Bob Wilson, who deliberately runs cars out of fuel for fun and sport and engineering research, got 122 and 132 miles: [WARNING] Running out of gas (Gen III)

Note that he started counting when the bottom pip started flashing, which is 20-30 miles earlier than DTE = 0.

 

Just an FYI, to add to fuzzy's comment...I drove 117.2 miles after the bottom PIP started flashing on that same tank I noted above. I had a tad more than a gallon of gas left. Keep in mind of the mpg. I was only able to drive that much after bottom PIP because of the 64+mpg I was getting at the time.

 

This an easy way to figure out how much farther you can travel. It is not dead on but really close.

The gas tank is 12 gallons and a warning beep will go off at about 10 gallon. This approximate when the car shows 0 miles left on the tank.

Look at the two numbers. Miles traveled (328.8) and cons MPG (59.6)



If you keep the MPG at 59.6 you should use 10 gallons of gas to travel 596 miles. This is when the car will show 0 miles left. Really you have 2 gallons more to go. At 59.6 * 2 (gallons) = 119.2 more miles before you really run out of gas.

Again this is not perfect but it is really close. I let the car run out of gas once and it was within 3 miles. I have put more than 12 gallons of gas in my car. Maybe 12.3

 

I have to ask, I bet I heard 20X or more if you run out of gas it is really bad on the fuel pump. Did anyone ever actually run out of gas and did it ruin the gas pump?

 

I'm happy to say I've never run out of gas.

My understanding is that running out of gas can cause problems with getting air in the line and then the pump not priming itself after putting gas back in. I know this is a big problem with large diesel vehicles like heavy machinery. Was at a worksite once when a bulldozer ran out of diesel and it was a big mess for this reason... you cant just put fuel back in and fire it back up. With smaller cars it may not happen every time, but it does happen.

In regards to running on "E" it's more of a degenerative thing. Doing it once won't harm anything but constantly running the fuel pump when there's very little fuel in the tank is hard in the pump and will likely reduce its lifespan for several reasons:

1. The pump is cooled by the fuel it sits in... If its not submerged in fuel the pump could overheat or wear more than a properly cooled pump

2. Over time all fuel tanks get a bit of sediment in them. The fuel filter hopefully blocks this stuff from getting in the lines, but that keeps the crud in the tank. If you're sucking the last bits of fuel out of the tank the fuel will be "sludge like" and that makes the pump work harder, clogs up the filters more, etc. If you've ever cleaned out a fishtank it's like that... The water is nice and clean until you start sucking out the bottom 10% where all the junk is resting. Ideally the gas tank would get cleaned out every 50k miles or so but in practice this doesn't happen.


For all the reasons above most cars will scream that they're out of gas long before they're physically out of gas.

 

I totally agree with your explanation, thank you for taking the time and for the details around the effects. Cavitation, and pump run out are really hard if not catastrophic on a pump. I just wanted to know if any one ever actually had experience with running out of gas and if so did it actually require a new fuel pump.

 

Yes, Bob Wilson has run the tank all the way down in the name of Research. No, he did not destroy his fuel pump.

 

... at least 10 times in a Gen II, and 3 times in a Gen III, IIRC.

I've done it only twice -- once intentionally, four cars ago, and once accidentally, five cars ago. Both predated fuel injection. No consequences.

Many PriusChat posters have accidentally run out of gas. The great majority had no problems. But some did run into problems: traction battery drained to exhaustion, ignition lockout requiring dealer reset, car not recognizing just one or two added gallons so it refuses to allow restart attempts. There have also been a few other poorly described reports that might have been pump or other fuel problems, or may have been unrelated failures that just happened to occur while the fuel tank was extremely low.

 

i ran out on my gen II. then drove until the battery quit and the dash lit up. added two gallons and was on my way. 30,000 miles later, no repercussions. not sure about gen III tho.

 

Thanks, I think if the pump would run for a long period w/o any fluid certainly it would fail, however I think the car will shut down long before the pump would actually fail, it is just an opinion.

 

Fortunately I have never ran out of gas.

In the past I have used Codyroo's formula 10X MPG dash reading which you may have heard of and I also have used a calculation of my largest error% MFD vs calculated (for me it is +7.65%) with my current MFD reading...then with the estimated current miles driven so far I divide the estimated MPG to get DTE.

Example - if I have MFD 68 mpg than 7.65% optimistic is ~63.2 mpg.
If I have driven 625 miles so far I can divide 625/63.2= 9.89 gallons used.
So I have close to 2.01g left. If I keep display around 68 then 63.2*2.01= 127.03 miles till empty.
Since my average % error is a little less than 7.65, I probably have a little more than 127 miles till empty. I just use the highest error % for a safe estimate.
I hope the math looks okay and makes sense.

Most of the time I don't let it get down too low. I usually have at least 1.5-2 gallons left in the tank.