Stopped for gas the other day with on 2 pips left... almost 500 miles so I had an idea that it should take at least 7 or 8 gallons... the pump cut off after 5, started the car and gauge immediately fell from 9 to 7 pips- no real surprise, put in almost 3 gallons more which was more what I expected- wondering why the pump cut off so early and how to avoid this again~
No sure-fire answer; it is either a function of the gas station's pump, a quirk in the fuel bladder system, or some combination thereof. My parents occasionally run into this early-shutoff circumstance with their Sunfire (guess-gauge reading not withstanding), so I'm sure it's not entirely a result of the Prius fuel system design. It hasn't happened to me yet in any car I've driven, including my two-year-old Prius. The only exception to that was a year ago when it kept clicking off instantly; turns out someone had slightly bent the nozzle just enough to cause problems for everyone using that particular pump. I'm still trying to imagine how someone could accidentally accomplish bending the nozzle... but anyway, that instance was obviously an exception. Some have recommended filling at the pump's slower speed, others have suggested trying a different pump.
I have found that the pump can cut off early if you're filling at full speed. So I've taken to filling at full speed for the first 4-5 gallons and then squeezing the handle at the slowest setting. Not on automatic, but actually holding the handle at the slowest possible fill rate. I have had very consistent fillups and mileage calculations (manaul calculation matching the energy display) using this method no matter what station or pump I fill up at. I have had the pump cutout pretty quick sometimes and I pull the nozzle out and release the back pressure of air in the tank. Then I'm able to fill up the tank. Took a little while to learn this but I'm very happy with the consistent results. Hope that helps.
This is one of the problems I have with NJ's full-service only law. I'm not the one in control of filling my car. I know how empty the tank is and how much should be able to go in. If it's way off (as in Barb's case), I can make an adjustment. With the full-service, though, when the pump clicks off, the attendant just clicks up to the next quarter and puts the nozzle away. I suppose we could ask them to use a slower setting, but we're really at their mercy.
Yeah, i'd say it's most likely a problem with the pump, and really rather unavoidable when using different pumps all the time. Personally, I always go to the same station to fill up, and almost always use the same pump, which gives me very consistant results. using different pumps just adds one more level of uncertainty in the results.
<div class='quotetop'>QUOTE(eagle33199 @ Sep 14 2006, 07:23 AM) [snapback]319468[/snapback]</div> Same here. If I have to use another station, I fill it slowly.