Fuel gauge way off

ok your off the hook!

 

Having worked with bladder tanks in aircraft, one needs to take the time to fill them completely, i.e. fill to the click, remove the nozzle for a few seconds and then re-insert and fill to the click again. This is somewhat difficult in a new Prius in that the seal at the fueling port is pretty tight which prompts early nozzle shut off. Also the bladder material tend to take a "set" like nickel-cadmium batteries do. That is if you continuously use only a portion of the capacity, sooner or later the capacity is semi permanently reduced; you must then re-stretch the bladder.

One way to resolve this is to slowly fill the tank in steps listening for the fuel to come up the the fueling entry pipe. Remove the nozzle and and observe whether the fuel is at the top of the pipe or not. If you can't see fuel, re-insert the nozzel and add more fuel. Continue this procedure until you see fuel. Now replace the cap and drive the car until you are ready to re-fuel. However, calculate the gallons used by dividing the miles by the mileage. The result is the approximate number of gallons used. When you re-fill, pump that number of gallons into the tank. It's a bit of a pain, but you will now start with a full tank.

 

I too burp the baby (take out the nozzle) and fill about .2 gallons after first shut-off until I see fuel.

At 57 MPG, my guage goes an average like this:
From blink to F
50 50 50 50 30 | 30 30 30 30 200
This is conservative, since I usually get in the upper 500's to 600's an the above only adds up to 550.

 

This confirms my observation that the tank has a 'memory' much like such batteries, and it requires a overdrive/stretch to get back the full capacity again. I have been always able to put 1 gal past the click also without it upchucking, so I'll stick with that.

Thanks for the confirmation.

So then I'm going to stick reading only my total mileage as I did with my Civic and ignore the gauge (which was also guess in the Civic). 550 is my safe tops and 550 is what I'll drive to, damn that meter.

 

After driving 410 miles in my 2005 Prius, manufactured August 2005, my fuel guage showed the first box of the 10 (which indicates a full tank). It did not flash as described on page 114 of the 2005 Owners Manual, nor was there the message of add fuel described on page 115. Trying to force what I thought was the correct operation, I stopped, and put the gear selector in park. Still no message or flashing fuel guage. Then, I discovered I could not get the car back into drive, no matter how many times I moved the shift lever with my foot on the brake pedal. (I couldn't go into reverse, either.)I powered off, and powered on to reset whatever software glich I got myself into, but still was stuck in park. Powering off a second time, and restarting allowed me to get into drive and drive to the nearest gas station (about 3 miles). Filling the tank to the first click of the pump took about 7.0 gallons. Pumping a second time to the second click added 0.77 gallons more for a total 7.77 gallons. Page 206 of the 2005 Owners Manual gives tank capacity of 11.9 gallons. Does this mean there are still about 4 gallons in the tank when box number 1 is lighted on the fuel guage? Is this worth a trip to the Toyota dealer for an explanation or fix?