Had something weird happen today.

Is it cold where you are? The bladder might not have stretched out due to cold weather. On a side note I always top my tank up.

 

Our gen 2s have varied by similar amounts on occasion, but that much is getting pretty extreme. I wouldn't worry about it. I'm curious what the next few tanks will be like, though.

 

maybe it was the pump

 

Never run on electric once you are out of gas. Neither you nor the dealer have a way to recharge the HV Battery if it can't start the car.

BEFORE the last pip starts to blink, get gas. (Gen 2 won't try to restart until you have added 3 gallons since the last time you tried to restart, don't try every gallon)

 

I have to ask.... Why do you wait for it to start blinking to fill up? Eventually you have to fill it up anyway so why even risk running out of fuel?

Just fill up when convenient after the gauge gets down to two bars. No stress that way. You can still track all the miles and gallons to see if anything is drastically wrong. The design with the fuel bladder already means the amount going in the tank will vary no matter how many bars remain on the gauge. Depending on weather, how long it's been running on two bars, etc., a "two bar" fillup has been anywhere from 6.8 to 9.3 gallons for me. It all evens out within a tank or two. Fill up sooner rather than later and don't sweat it.

 

Not to mention the fuel pump is cooled by the fuel in the tank. When you run the tank that low the pump is above the gas level and can’t cool the pump as well. Does it hurt the pump? I don’t know but it can’t help. Pump goes you need a whole new tank, and that’s not cheap.

 

Just be aware that refusal to get gas at two pips, means you will be walking with a gas can (repeatedly if it is less than 3 gallons) to hope you can restart your car, sooner or later.

 

It saves no money to get gas on fumes, compared to getting gas with a decent reserve. The Prius does not get any better gas mileage with one pip than ten.

As far as time, how inconvenient will it be to march back and forth to your car repeatedly? Call a friend to have them drive you back and forth to get at least 3 gallons in it before you try to restart it? What are the odds that it will happen on a day you have time for that?

(Gen3 and Gen4 Prius drivers fuss about how unreasonably large the reserve is on a Prius. Toyota reacted to Gen 2 drivers hating that they ran dry)

When I owned a Gen2, I gave the following advice:
Get gas at 3 pips with your mother in law in the car. Nothing could be worse than stranding her.
Get gas with 2 pips with your spouse in the car, you will be reminded of it your whole life.
Get gas with 1 pip, if you have some one to help carry gas.
If it start blinking, get gas NOW.

If it DOES run out, stop NOW. Neither you nor the dealer has a jump starter for the HV battery, it takes them about 3 weeks to order that.

The Gen2 Prius computer does not see less than 3 gallons as more fuel. You can add one gallon at a time until it pours out on the ground, if you try to start each time.

Repeated failures to start (5?) will set a code and it will need to be towed. Don't try to start until you have the gas.

The car may be sluggish for about a mile after you gas up. It is normal. you just drained the HV Battery before you realized you were out of gas (it won't do over 35 MPH)

As you may notice, this is been there, done that (twice) advice.

 

I've owned my '07 for about 16 months now, so have been through all seasons. Cold makes the bladder take less gas for me. I have recently discovered inserting the nozzle upside down helps put a bit more gas in. Even at its worst I still have about 350 mile range.

 

Unfortunately, with a Gen II Prius you're stuck with an inaccurate gas gauge. You'll have to go to Gen III or IV for that. When you mention 250 mile drive in a month, I'm confused. How many miles per day or per month are you really putting on the car? Is it 250 daily or one long trip per month? Is the 250 one-way or round trip? I would still like to to try and help you solve your dilemma.

You might need re calibration of your gas gauge too. The gauge should not be flashing at 190 miles. I have averaged 43 mpg over the 2 1/2 years I've had the car. My average fillup has been at 315 miles and I have never seen the gauge get down to flashing. I do know a re calibration is not difficult and done from the driver's seat. No tools required. Maybe someone here can post the instructions for you.

 

To be fair, it probably gets colder in IN than CA. The bladder capacity is very dependant on the temperature during the fillup. In cold weather the tank seems smaller.

 

Just to pile on...for no apparent logical reason...
Yes, I would recommend a tweak in your fill up protocol. Waiting until the last pip starts flashing is IMO pushing it a bit too far.
But it's not a Dante's Inferno warning...you've evidently never run out of gas...yet. For all the reason's already stated, NOT pushing the Prius to the pip blinking level, is probably a good idea.

As far as your mysterious tank capacity fluctuation, I wouldn't worry about that either. Gen 2 gas bladders are notorious for having their own fill personalities, that change with temperature, age, and with shut off quirks and fill speed of individual pumps.

 

While I have at times gone over 30 miles with it blinking, not after it ran out of gas after 7 miles of blinking.

From an emissions point of view, the bladder was great; but owners hated it.

Others have reported shorter distances, but face it: you never want to be within 7 miles of dead on the side of the road.