2005 Prius only takes 5 gallons of fuel

there are some threads here on the proper way to fill a finnicky gen II gas tank.

 

If he hits that, perhaps try rotating the nozzle so that it's sideways or upside down? I wouldn't do that always... just try it as a test.

If that doesn't help, try Gas gauge didn't show empty | PriusChat. I don't think he's got much to lose at this point.

The guess gauge and bladder in Gen 2 are a bit quirky. There's even a joke about it at Attila Vass's visit w/ the Chief Prius Engineer | PriusChat.

 

Have him calculate this actual MPG and compare it with what the MFD is reporting. If the MFD is accurate, he could attempt to drive until 10 times the MFDs repoted MPG. This will determine if it is a bladder filling issue or a gauge inaccuracy. He should be prepared to run out of gas and make sure to avoid a dangerous situation.

Avi

 

i recall reading a post about filling very slowly and another one about trying different gas stations.

 

If your coworker consistently can only put five gallons in at one pip when filling at the slowest fill rate, I would recommend that he reset the inclinometer. cwerdna's link will take you to that info.

The Gen 2 bladder is fussy, but most of the time it will be consistant.

Ask your coworker is this every tank at one pip for five gallons, or occasionally. If it is all the time, the inclinometer needs to be reset. If it is occasional, I would suspect the bladder.

FWIW, it seems to be easier to fill the bladder when you get down to 2 pips or higher rather than 1 pip or the flashing pip. When the pip is flashing, the bladder is almost collapsed. It seems that the bladder expands more easily the less it is collapsed. Some users in the past have reported filling the bladder, then going 50 miles or so and already see one or two pips disappear. It seems that when the bladder finally expands the guess gage thinks the tank has less gas, and therefore changes the number of pips on the guess gage. Once the bladder has fully expanded, you can then put more fuel in. Cold temp's affect the bladder drastically. I have experience that there has been more than one occasion that the number of gallons pumped in the bladder did not agree with the amount expected based on MPG. (more than 12 MPG difference), and then the following tank the MPG will reverse. I call it a bladder moment and you can see it plainly on my fuelly link.

Hope this info helps you and your coworker. Also welcome to Prius Chat!

Ron

 

Guess Gage = Fuel Gage (With the Prius sometimes it is a guess)

Pip or Pips = The little squares that appear on the Guess Gage

 

My guess is the issue is with the gauge and not the fuel tank. As I understand it the bladder is semi-flexible and allows the tank to shrink and grow a touch but not really move or twist. However, if the car was purchased used and has had the issue since purchase it could be something with the tank. What I have noticed is that in the summer when the bladder is flexible I have about 70 miles more range than winter so I have just assumed that the capacity can vary by at least 1.5.

I had a similar issue - when the car showed 1 pip it took only about 8 gallons. I tried resetting the inclinometer a couple of times, but it was no help. What I finally did was on a day when I needed to do a couple hundred miles of driving I figured out how many miles I should be able to go on 10 gallons (I believe that max with the bladder is a bit over 11.5). I then put a gas can in the back with 4 gallons and set off - yes, I know that this is not super safe, but I did it anyway. I drove a ton of miles with that last pip blinking and when I hit my mileage I stopped for gas and put in right around the 10 gallons I thought that I would need. After that the gauge was a bit closer to accurate, but more so, I had a level of comfort with the gas gauge.