Do we still have to deal with that silly flexible gas tank?

The gen 3 does not have the bladder, and the gen 4 does not either. My gen 3 gas tank is pretty consistent

 

my gen 3 is spot on, with 8 bars, and 8 gallons.

 

The gen 1 did not have the bladder either AFAIK.

 

Why is this a problem? I'm being serious. I just got a 2005 and would like to know why this bladder causes so much headache? I've read so much about it here. I've only filled up once on the 2005. I will probably get 350 - 400 miles on my current tank. MFD says 49 mpg. I filled up a little under 8 gallons the first time on my 2005 same as per usual on my PiP with 1 or 2 bars. I've never gotten 500 mile gas only tanks.

You're describing symptoms that is normal for my PiP. Everyone here confirms no bladder in a G3. 400 mile gas only tanks and 8 gallon fill ups is normal on a PiP. Why is it an issue on a G2? Consider me a newb on bladder conflicts.

P.S. The Safeway that I fill up at prematurely cuts off for my PiP so if I drive some 10 miles after fill up, I lose the first bar. The only way is to to keep topping off 10-20 times which I am unwillingly to do. So I actually experience 1 gallon is slightly more than 1 bar.

 

In the winter on Gen2 we can get down to 300 or less miles. That's where it's a pain. The oft stated reason is the bladder does not expand as much in cold, but I wonder about that. Of course our MPG in winter goes from 48 down to 42 or so tops and then you cannot fill the tank more than 8 gals.

 

The bladder was wildly successful as an emissions control device, as an owner, it had some issues.

Some owners could only fill their tanks at an incredibly slow pace. (It helped to open the cap before paying, to allow some air in)

The variable amount of miles traveled before the first pip disappeared was a mild issue, but the variable number of miles you could travel after the last pip started blinking risked running out of gas which is a pain in a Prius. (it takes 3 gallons before it admits it is not empty, and no one has a 3 gallon can)

Past performance was no indication of future miles to empty.

As the bladder became colder it folded more poorly, so cold weather tanks were gallons smaller than warm weather tanks. (Unlike other cars, it was best to get gas in the heat of the day)

You needed a spreadsheet to track MPG as each tank was a different value, you needed a running average to determine your mileage. Many of us with North American Gen 2s joined fuelly.

 

Do you mean the bar is blinking when you fill up you can only put in 8 gallons? Because again, that's what happens on my PiP. I don't find that unusual beyond the DTE being overly conservative. The only way I can fill more than 8 gallons without topping up is to drive the car beyond DTE. I've dared to go as far as 50 miles beyond and it still only accepted 9 gallons max.

Now if JimboPalmer above is saying the variance is 3 gallons and in the dead of winter I can only put in 5 gallons with the last bar blinking, then I may have a problem with the bladder.

 

As pointed out, places that have winter meant the tank actually held less when the plastic was less flexible.
For those tracking MPG by measurement, it a wider range of variance in fill ups.

 

No matter how messed up your fill ups are, it will even out in a tank or two. Variations cannot persist.

 

Didn't bother me much - I averaged 9.10 gallons per tank for 267 fillups in my 2008. Three times I pumped over 11 gallons.

 

What you notice on a Gen2, is that in hot summer, you can get almost 150 miles before the first little pip goes away. In the winter the first pip goes away much sooner, as if the level filled to was lower. Of course PiP has a smaller tank so add ~1-gal to correlate

 

Never had a problem discussed above in Pearl (GII). Always filled till I saw fuel in the neck. But then I hardly ever waited till it was empty to refil. Usually I filled up at around 1/2 a tank (on the gauge). I suppose keeping the bladder extended helped.

The fuel gauge won't work properly unless you put in a minimum amount of fuel, and that amount varied a bit car to car. That is, it doesn't think any fuel went in until that minimum amount was added. I did experience this a few times. However, it quickly sorted itself out once it began recording dropping fuel "pips". Once it never recovered until the next fillup (displaying less fuel than it actually held). All this on highway long distance trips. But I don't think this had anything to do with the bladder, rather the quirky computerized fuel gauge system was the culprit.

 

While that is so, it meant comparing if changes affected fuel economy difficult.

I had started only filling the tank on the gen2 to 1/2 to 3/4, with a top of once a month. People were reporting seeing better fuel economy on the last half of their tank. I didn't consider the weight of more fuel an issue if this was so, but rather a factor of increased pressures on the fuel by the pump inlet. Fuel pumps aren't peristalic, so extra pressure on the intake side could push more fuel into the fuel line than called for.

There is the head pressure of the fuel above pushing down. With less fuel, there is less pressure. Like weight, this probably had little effect. Otherwise, a marked increase in fuel economy of other cars running low on gas would be seen. The fuel bladder was a dynamic other cars didn't have though. When completely fuel, it could be stretched out to a small degree, and it may have been squeezing on the fuel.

It is possible there was another variable I haven't accounted for, but I did get better fuel economy with not completely filling the tank.

 

My 2003 does.

Bob Wilson

 

I can't confirm that the 2016 tank does not have a bladder, but it does have something new, what I would call a pressure relief valve. From the manual page 262:
"The tank of your vehicle has a special structure, which requires a reduction in fuel tank pressure before refueling. After the opener switch has been pressed, it will take several seconds until the vehicle is ready for refueling"

So when you push the button under the dash, there is a delay of a few seconds and then the filler door opens. There is not a direct connection to the filler door like a cable. On manual page 265:

" When the fuel filler door cannot be opened by pressing the inside switch, open the back door and remove the cover under the luggage compartment light. Pull the lever backwards and check that the fuel filer door opens. Using the lever to open the fuel filler door may not allow for an adequate reduction in fuel tank pressure before refueling. To prevent fuel from spilling out, turn the cap slowly when removing it. During refueling, fuel may spill out from the filler opening due to air being discharged from inside the fuel tank. Therefore, fill the fuel tank carefully and slowly."

 

Interesting. I assume flex tank died with Gen2.

The whole idea of the flex tank is to avoid releasing vapors to the air, so I wonder where that excess pressure bleeds off to? Probably not to the air.

 

The gen2 needed the bladder to qualify as AT-PZEV under CARB because the traditional vapor capture system Toyota was using in other parts of the world wasn't good enough. With the gen3, those had improved, and made the bladder unneeded.

 

Everybody likes an easy question to answer.

Yep..the flexible gas bladder is no more.

You will get plenty of advice, and there are numerous threads on how Gen-2 owners have dealt with Gas Bladder issues.

These solutions range from total frustration...to various mojo's being applied to the refueling process.