Distance Until Empty

I don't think the bladder offers the luxury of a DUE, it's just to variable. Temp and several other things conspire against accurate fuel load information. How far can you go? I've gone way over 400 on mine and still no blinking fuel gauge, YMMV but looks like your on your way to 450 or 500, the blinking will tell you your experiment is over.

 

After a few tanks, you'll begin to get an idea how linear your gauge is, and how consistent it is. But there's too much variance between cars for anyone to say for sure how yours will behave.

An important number is how much gas you can get in when the last bar begins to blink. That'll give you a rough idea how much you still have in reserve, keeping in mind that a new bladder in cold weather may hold a LOT less than the rated capacity.

The mpg figure on the MFD should be reasonably accurate, and that will give you a good idea, allowing for uncertain tank capacity. But don't trust it down to the last drop. People have run out of gas calculating they could go X miles on the tank, and they ran dry 20 miles sooner.

The early-build cars apparently still had 1 to 1.5 gallons remaining when the blinking started, but I gather they fixed that.

Anyway, you won't really know except by observing your own car. Don't assume your gauge is linear until you've seen how it behaves. And don't trust it too much until you've observed it for a few tanks.

 

This past Saturday, I finally drove over 500 miles before filling up.

There was a chime, the last light started to blink, and the MFD flashed "Low Fuel" for a moment, right about at 500 miles.

When I fueled up a few miles later, the bladder only took in about 9.7 gallons. So if you believe the manual, there was well over a gallon, almost two gallons, of gas left in the car.

I fill up with the gas-pump-handle clicked on the "slow" setting, mark how much gas it took at the "auto-shut off," and then try to squeeze another half gallon into the bladder.

You can read all my gas-stats here:
http://www.w8kc.com/priusmileage.htm

The car is a late July build and already had the gas computer mod.

 

A lot of people think a " distance to empty" display is not possible in the Prius due to the bladder and/or the gauge being inaccurate etc etc. However, those things really do not matter. A ' distance to empty' gauge/display doen't work by assuming the amount of fuel when full, assuming average mpg and then calculating miles travelled. It is far more sophisticated. It works just like the gas gauge, ie it also fluctuates depending on slopes( plain vs uphill,or downhill) and conditions. If you start going down a really long hill, your DTE figure starts creeping up and vice versa. Often, for no reason, the DTE figure will change radically upwards or downwards( just like the fuel gauge losing some bars qucikly) and is never the same if you turn the car off and start it later on though it might be close. A DTE in the Prius would be tied to the gas gauge and would simply convert the amount of fuel the computer thinks is remaining and multiply it with the current mpg to get the figure. Ofcourse, as in any car, it would be an estimate and you may not be able to drive to the very last mile indicated or may be able to drive beyound zero!! I think Toyota avoided it as they believe it is bad to run the Prius out of fuel for the battery. If the last bar blinked but the DTE said 100 miles( assuming around 2 gallons are left and the mpg were 50), many people would wait until the DTE said 30-50 miles left till empty thereby incresing the chaces of error. I have driveb my pre Prius BMW for several miles when the DTE said 0 and inversly have run out of fuel when it said 11 miles left.

 

Judging from posts in this forum, Prius owners, apparently eager to test how far they can go on a tank of gas, run out of gas ten times more often than drivers of other cars, and with potentially far greater consequences.

 

Gurmail as you stated the DTE uses the fuel gauge to determine the distance till empty but the gauge is totally inaccurate as you will find out if you go thru a cold winter when the gauge read full but you can only put 7.5 or 8 gallons in the tank. The computer thinks the tank is full at 10 gallons but the bladder restricts the capacity to 8 the DTE is out of wack. DTE's always assume full on the gauge is full capacity. On a Prius it seldom is. And never in cold climates. But the computer doesn't know that, and blindly computes as if it was.

 

i believe that i have just under ¼ of a tank when i reach my last bar.

 

Frank, you are right. My point is that the DTE will also be inaccurate and be affected by the temp etc, but is possible. DTE are somewhat inaccurate in all cars. In the Prius, Toyota believes it is bad for the battery to drivw without ICE( out of fuel) and if there were a DTE saying 70-120 miles to go when the last bar flashes, many people might want to wait a bit longer before filling up. Once, in my proir BMW, tge DTE said 70. I drove a few miles back and forth to the train station for a couple of days. The DTE kept on fluctuating. It would start at 40-50, would go down to 28 and up to 35. Then, on the weekend I went to get gas. The DTE said 25 at start up and then went to 15. I risked going to a gas station na mile away ( cheaper) and ran out of fuel when the display said 11. Conversly, on another car I have driven 10-15 miles after the display said 0. But, like the prevoius poster, I believe in filling up early and not pushing it.

 

just as a note...i have had 4 toyotas in the past and all of them have a big red "fuel" warning light that comes on when the gas is about ¼ of a tank...

of course when you still have the analog gauge there to go by, you soon learn to ignore the light... although it is rather bright at night and is smack dab in the middle of the instrument display.

 

It's not really the battery as it's protected from damage but running a Prius out of gas and driving it on electricity only leaves the fuel pump running in an empty tank and overheating. The tank being sealed with the pump inside, means a burnt out pump equals a new tank. Not cheap, and probably not warrantable in Toyota's eyes. I know some have done it and not had any harm done to the pump, but why take a chance. When the last bar blinks gas up how simple is that.

 

I think everyone is missing another factor of DTW or DUE. I tend to try this myself. At about 500 miles, the MFD says 55MPG (sometimes higher, sometimes lower). OK, so now I calculate how much gas I've used. In this example, 9.09 gal.
So, 11.9-9.09, I get 2.81 gal. left. Assuming how much gas was originally in the tank, how far we've gone, and the MPG is accurate, the remaining gas is accurate. The problem is, we can't continue assuming 55MPG. We may hit traffic, and cause the instantaneous, or even short range MPG to be quite lower. Thus for the last 2 gallons, we may only get 30MPG, and can only go 84 miles rather than the 154 we will probably assume.

I think the constant change in MPG is why the DTE display in other cars fluctuates.

 

Exactly. Also the amount of fuel deemed to be remaining might change with slopes, movement etc.