NO fix for Prius Gas Tank Filling Up Issues

To pile on... I have a 2004 Prius with about 150,000 miles (I'm likely to cross that mark in the next week.)

I live in Portland, Oregon, where it rarely gets below freezing, even in Winter.

In the past year, my bladder has been getting less and less flexible (I imagine that's the reason.) Last Summer, I rarely had a fill-up above 8 gallons. The past few months (again, it has rarely gotten below freezing,) my "blinking last dot" fill ups have been on the order of 6.5-7 gallons.

It has been years since I had a fill up over 10 gallons. (Even driving on the blinking last dot for far longer than I felt comfortable, just to test.) It was about three years ago that I last got >400 miles on a tank. I have *NEVER* gotten an 11 gallon fill-up. Not once. Missing nearly 10% of the advertised capacity up front is wrong, missing nearly *HALF* the advertised capacity is borderline criminal. When I take it in for the 150K service, I'll be bringing this up. I'll report back.

 

sounds like my bladder.

 

I bought a used 2004 Prius 2 and half years ago. I typically fill it when I get down to 1 or 2 bars. The most I could ever fill was around 8 gallons. I found on this site about recalibrating the gas gauge and I tried to recal the gauge. I also changed my habit about when to fill up. If I fill up with 8 gallons, and look at my mpg and wait till I have gone as far as 8 gallons times the mpg before filling up. Each time I try to stretch it out farther on each fill up. My best so far was 520 miles and filled up with slightly 10 gallons. I think I saw the last bar flashing and the add fuel message on the display.

I still don't know how much my tank holds but at least I know it holds at least 10 gallons. When I get to the last bar, just for safety sake, I take a gallon of gas with me just in case I don't make it to the gas station.

 

I just puchased a 2007 prius and was filling up and kept trying to top off the tank and to my surprise when I pulled the gas nozzle out of the fuel tank I got a gallon spit back out onto me, the car and the pavement. After the clean up I have found that I have driven 140 miles and the fuel tank still shows full. Not one click missing.
Whats up with this?

 

When you get a good full fill-up, there is as much as 150-160 miles @50MPG before the first pip goes away. The subsequent pips go away much faster as low as 25-30 miles.

I've had one experience where the tank over-filled...assume it is a pump problem.

 

Ditto, I go 90-140 miles before the first pip goes away depending on how much I top off. The fuel gauge on just every car doesn't represent the actual full and actual empty of the fuel tank. It's always been like this. People are starting to notice now that we are getting into digital gauges. As to why this is, I don't know know. I understand why they leave a cushion for empty but I don't understand why full isn't full.

 

Thanks for the feedback. Other than this issue the car has been delightful and feels like a dream and new car even though 2007 with 129k on it. Loving this car!!

 

My 2004 Prius had a "Guess Gauge". My new 2016 Prius has a very predictable digital gas gauge. It has 8 ticks between full and empty and each pip corresponds to 1 gallon. When at empty there are about 2 gallons left. Above full there is between 0 to 2 gallons depending on how I topped off the tank at the gas station.

JeffD

 

Good point for Gen2 anyways...well I take a guess at why they have slack in the first pip. My tank only fills up to 7 gallons now even in warm weather last week, versus say 9 gallon in summer. So they want folks like me to see FULL even though it is 25% empty from the getgo in winter. I personally attribute this to higher vapor pressure in the winter fuels. In other words, I speculate that fuel vapor pressure variations impacts how much fuel you can get into the tank, and to "paper" that over, they make the gauge say full at the 75-80% full mark.

 

It's been pretty well documented around here that topping off a Generation II Prius is a bad idea. A search should turn up a lot of references to that effect. There's also a pretty interesting thread here:

The Prius Geyser - The Show - Car Talk Community

 

Guess be great article to read if I knew about this prior time owning. Now I know. Will not top off again. Appreciate the info. I finally saw the fuel gauge come off of full at the 180 mile mark. So when you fill up do you leave the pump to stop when it decides? Do you pull it out half way and then fill till it stops on the first time?
How do you get the most without getting gas vomit?

 

Because of the bladder tank the actual fuel capacity will vary a bit from tank to tank. Many of us find it's easy to just fill it when it's convenient after you see it's down to two bars or less on the gas gauge. Fill slowly using the slowest automatic setting as opposed to holding the nozzle. Wait until it clicks off by itself and you're done. Don't try to force any extra fuel into the tank.

 

I just let it click off. My car does not seem to accept any top off...the pump immediately shuts off once it is full to the first click...then I cannot get any more in there. This time of year it is frustrating because it clicks off at 6-7 gals.

 

Not overstated at all. I have an 08 Prius, It will only accept about 6 gallons. I once got it to accept about 8. But never got in more than that. It's really annoying because I have to stop at the gas station twice a week. In my old Prius, I get a full 11 gallons in and I only go to the station once every 3 weeks in that one. It's almost enough to make me park the 08 and just drive the 01. Anywho not only can I not get a full tank every time I try to pump gas in it shuts the pump off. so I literally spend about 10 to 15mins just trying to force in more gas until it starts to spray back out at me. I find it pretty dangerous. I've tried pumping the gas in with the nozzle upside down, sideways. and I tried using the slowest setting. nothing works. I'm going to try to get in as much as possible at the pump, then try to get the rest in with a gas jug and see if that helps. At this point, I'm not even sure what to do. All I can think of is just to try to replace the whole gas tank and evap system and hope I can get a few yrs of normal operation. Oh, yea I'm a contractor so I have the records to prove it too. I keep most of my fill-up receipts. Sooo many 6-gallon fill-ups!

 

sometime I get a gas pump that will pump really really slowly if I want to ...then I can seem to get as much as gas in as I have patience to stand there.

 

My 2007 Prius taking only less than 3 gallons even when the gauge is down to one pip! I have to go to get gas everyday! There should be some idea to expand this bladder before filling up gas, so at least five gallon of gas you can get per visit to gas station.

 

It seems to me the with the thermodynamics of the bladder as it ages it holds less. after many winters and summers it loses its flexability to the point that in extreme cases a total replacement is needed. Like a BEV with a short range (LEAF) you just have to fill up with whatever your tank will hold more often. 8.5 gallons for us is the norm. If I got down to 3 gallons due to shrinkage....I would replace the entire tank.

 

In addition to a bladder (which gets talked about all the time, because it's kind of unusual), your Prius also has an ORVR system (which lots of other cars also have, so maybe that's why Prius owners sometimes forget to talk about it).



In cases where the car is rejecting even really small (like not even 3 gallons) amounts of gas, it is more likely a component of the ORVR system failed or clogged or liquid-filled, than anything to do with the bladder. Then one just repairs that problem, and returns to the normal Prius bladder experience of slightly vague 'full' levels.

 

So the components of the fuel system can be replaced separate of the Bladder? Nice. I thought everything was internal and required a full tank swap. Thanks for the knowledge.

 

What's in the tank is only available with a full tank swap.

But as the diagram shows, not all of the EVAP and ORVR components are in the tank.

You can find more details in this post and the rest of the thread it appears in.