[WARNING] Running out of gas (Gen III)

What you are missing is 'knowledge'. Bob has done the 'out-of-gas' scenerio all the way back - when he took possession of his brand new Gen I , so that those who are so slow to let "out-of-gas" happen accidently will know what to expect, other than being stuck, out of gas. Some want to know. Will the car restart with a half gallon? ... 1 gallon? 2 gallons? ... will the battery be damaged? These are the nuggets we tinkerers pass on to others. I think the last nugget to be experienced is what happens to the PiP, when your gas runs dry, and you're on your last mile or two of EV. Will the PiP go into a turtle mode the way many EV's do? Or will it respond like the standard Gen III - not letting you even enter EV mode w/out gas. Or, if you've just switched to EV as you're sputtering out of gas, will you be able to remain in EV? Enquiring minds want to know. If you don't want to know - that's ok too.

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I guess I don't want to know (at least not first hand ), and I got the research part at the beginning of the thread, and think it's cool, but there are *lots* of posts about people's own experiences running out of gas. There are so many, I figured there had to be some "logical" reason that people are running their tanks dry.
I just didn't want to be the only guy who wasn't told... you know, the guy walking around with the sign taped to his back reading, "Don't fill my tank!" that everybody laughs at, but nobody will tell him about the sign.

So where is that &^%$in mirror???

 

Why should condensation be an extra concern with ethanol? Isn't filling up with E10 roughly equivalent to putting more than a gallon of gas line drier in the tank?

The only moisture problem I've heard with E10 was when it was first introduced locally, by government mandate. It soaked up and flushed through years of collected moisture in the fuel distribution and storage supply chain, all at once. After that, moisture couldn't collect enough to be a problem.

Your 1/2 tank rule, applied to my last non-hybrid, would cost me several dollars per refill on one of my regular trips. It wouldn't buy me any real peace of mind (math is easy for some of us), only permission to shut off the thinking cap.

That trip is 400 miles each way, plus an extra 20 miles or so during the stay at the other end. That old car goes the 330 miles between affordable fuel stops, and has comfortable safety margin (for me, not for you) even when lousy conditions cause the fuel needle to drop below E. A surprising amount of its fuel capacity is below that mark.

However, its range to the 1/2 tank mark is only 145 miles. Your half tank rule would demand refills at 146 miles (touri$t trap prices$) and 285 miles (al$o expen$sive, and the location of my long ago price gouging experience in a short fuel range car). The half tank rule would have me either running 82% of the trip on overpriced fuel, or making some extra stops for partial refills to get that overpriced fraction down to a mere 47%.

By better characterizing its fuel range, I can get that overpriced fuel fraction down to 0% and still be comfortable.

My first car had much shorter range, and negative reserve margin to E (i.e. it went dry above that mark). In theory, on some journeys, it could be above 1/2 at the 'next gas xx miles' signs and still not make it. So I paid higher average fuel prices, learned fuel planning, and made sure future cars had better range.

Old planning lessons die hard.

Nearly all of those are 'uncontrolled'. Engineers tend to prefer the better information of controlled experiments, when practical.

 

i have done this with almost every car i had and not quite sure why. i think its for the thrill of getting stuck, kinda like gambling. the more i think about it.... i think, my real reason is to wait till i can get to my fav gas station and being lazy. i can get away with driving from oc to la with the gas blinks, then go to work tomorrow with out pumping gas. esp helpful when your late for a party then tired while going home(which happens often).

 

I did this just because I was trying to get down so I could take advantage of a 25 cent code and I was running around helping my son in moving. I had never taken the car down to 0 mpg but the 4 or so times I had taken down to 50 miles i rarely got more than 10 gallons. The meter was flashing the whole time and most of the people that were in my car (my nephew told everyone i was running on empty). I got kinda nervous and when I finally did fill up, I took just a little over 10 gallons (i topped it off...)

I do want to warn people that I usually do get gas at a 1/4 tank so that probably has some bearing to the extra miles...

 

Dri-gas is methanol, not ethanol. Methanol has it's own problems, but it is good at dissolving water in gasoline. While it is true that today blenders put a corrosion inhibitor into all E10 blends, it's effectiveness is limited. It is also true that auto manufacturers are cognizant of the problem and had greatly upgraded the quality of materials used in fuel systems. However, I am not willing to put all my faith in remedial measures. Keeping water out of the fuel system is the best way to avoid problems. Michigan has both high humidity and daily temperature changes - thus the advantage to reducing air volume in the tank.

Did I not make it clear that one of the factors I was taking into account was the increased time between fill ups now that I'm driving my Prius. Thus your comments about your old non-hybrid and taking long trips are not responsive to my question. On a trip, when you are burning through a tank in a single day, or even multiple tanks there is no opportunity for condensation to form. I am not obsessive-compulsive, rules are guidance not laws.
On a long trip I still follow the 1/2 tank rule - but the rule is my bladder - I stop whenever my bladder is 1/2 full.

Not old planning - careful thought.

 

Iso-HEET and some other gas line dryers are isopropyl alcohol. Because methyl, ethyl, and isopropyl alcohols are all miscible with water, do they all not have similar effects with moisture in the fuel tank?

I have generally divorced pit stops from fuel stops. The cheapest fuel often comes with no restrooms, or hideous restrooms, and doesn't fit the travel companion's bladder schedule. The most scenic and/or pleasant restrooms don't have fuel available.

 

Thank you, Bob, for being the point man on Prius knowledge.

I think we've all learned something here. Some people are gamblers, some aren't, and some force their will upon the world regardless of the risk.

Me, I'll just fill up when I start feeling queasy. If I need to go a precise, long mileage on a tank, I'll buy a bigger tank.

 

Maybe it's because I grew up in the west, where sometimes there were long miles between gas stations, but I tend to gas up fairly frequently when on long trips. As my dad used to say, "It costs the same in the long run whether you add it a little at a time or all at once."

For daily commuting, I go by gas prices, because over time there are differences. If prices are rising, I buy more often to get gas while it's cheaper. If prices are falling, I buy less often so I get lower prices.

 

No. With ethanol you get phase separation at relatively low volumes of water. And adding either methanol or isopropyl alcohol to ethanol bearing fuels that have undergone phase separation has a number of bad effects. If you ever do get phase separation in ethanol/gasoline fuels, the only wise course of action is to completely drain the fuel system.
It is suitable to use a stabilizer like Sta-Bil, but that would certainly negate any savings from searching for cheap gas.

Yes, I realize that our fuel systems are far better sealed than that jar, but,again, that's why I made the point of going weeks between fuel-ups. Fuel system repairs are expensive, buying gas every week is not.

 

Quite simply there's no excuse for running out of gas unless you are a moron. As someone posted above, fill up regularly. I fill up around the half way mark as I would hate any sediment that's resident in the tank to get dragged into the engine and cause even more problems and aggro.

 

Dittos what Skateruk said. Years ago I had a wrecker service. The easiest money I made was running 2 Gallons of gas out to people that refused to fill their tanks when they had the opportunity. AND,I averaged 3 calls per day. And that was when gas was 50to70 cents a gallon.Some things never change!

 

I bought my 2014 gen3 prius april 2014. I am now in my 4th month and have let the tank go down until all the bars were out including the last flashing bar before I filled up. The beep sounds once when last bar is flashing and beeps again when the flashing bar goes out and there are no gas indicator bars and I was still able to get to a gas station nearby to fill up. I got away with it but it is not good so I wont do it again - best to fill up on the last bar or 2.

 

While the last bar does go out on my 2014 Forester, I have not witnessed such on either of my Prii, nor recall anyone else mentioning it.

Can you give us more indication of how far down this happened, such as distance from initial flashing or how much fuel the refill took? Any chance it is a new 'feature' for 2014?

 

Living in earthquake zones, I now aim to refill at 50%.

 

I'm afraid I don't understand why a normal intelligent person would let their car run out of gas. It cost no more in the long run to full at 1/2 1/4 or E ,you use the same amount of gas. When you run your tank low you suck up all kinds of debris and moisture into your fuel filter. Some cars (and I don't know about the Prius) have the fuel pump in the gas tank and it is cooled by the gas in the tank. It can overheat and fail prematurely. Running out of gas can be costley and dangerous depending where you are.

 

Is all gas the same price where you travel? Where I travel, gas has enormous price differences, and the 1/2 tank mark often coincides with the highest possible price.

 

I learned this when Hurricane ''Katrina'' came calling. Although-- I had enough smarts to fill wife's Lexus and my Z-71 [ and motorcycles ] before, many did not and gas was scarce. I could hardly keep my generator running------- 1/2 tank is empty for me now. Also a good tip on keeping fuel pump cooled.