NO fix for Prius Gas Tank Filling Up Issues

While this doesn't help current owners, the new 2010 has a bladderless fuel tank. The problem should be gone.

Tom

 

If it can be called a "problem" at all... ; )

 

Well, this past week, on my 1st full tank of gas, I kept track of each pip and mileage. The one pip showed up at 397 miles, started to blink at 420. At 470, the display said to fuel up before starting. It did start, didn't want to push my luck and filled it up at 476; pumped 10.18 gal. I would say on that one tank, that it behaved normally and it seems that it had the right amount left, 1.5 gal. See what happens on this tank.

 

This is a long thread so maybe these things have been covered. My car barfed up gas once when newish and it was very cold, the tank very empty and I filled up at the highest flow rate. I read it was better with the bladders to fill them slowly so now I use the slowest speed where the handle can be set to automatic. I also withdraw the filling tube as far as possible (don't recall why I started doing this). I also heard on Click and Clack that fuel pumps are now submerged on most cars and they are lubricated by the fuel so running out of gas is really bad - leads to pump burn out. So the gauges are set to read empty when they are not empty to keep the pump protected.

 

An 11.9 gallon tank effectively being a 7 gallon tank is a problem.

 

So is premature fuel pump burnout from running gas tank low. See ctmurray's comment.

It's for our own good. Saves money from fuel pump replacement due to inability to put gas in a car at the appropriate time/level. Not sure why that is so hard. Many things in life are variable and not the same from day to day or week to week. Why is it expected that variance is bad? Nature itself (by it's very nature) is varied and differs all the time...the Prius is just another example of nature's perfect variances.

 

Another data point with my 2006: Temperature was 37°F, I had driven on one pip for about 15 minutes; the tank took 8.3 U.S. gallons to the first click, which is where I stopped filling. This is a normal fill for me at this level, for which I am perfectly satisfied.

Tom

 

I agree, Toyota should not have put an unreliable bladder in it. Then the possibility of premature fuel pump burnout would be reduced. If instead you have a system that won't fill to anywhere near its full capacity and that apparently can run out at its own whim even if it is displaying more...well, that's not good is it? Or perhaps you like replacing fuel pumps.

 

No one has said they run out when they still have 2 bars displayed on the fuel gauge.

 

Actually, on a recent thread someone described that very problem. I believe the person was a two Prius owner but I might have him crossed with someone else.

You shouldn't have to worry about running out with even 1 bar on the gauge. Until you hit zero bars you should not be out...(not sure if it can even display zero bars. Filling within a few miles of the flashing pip should be enough.) If you buy a new car and it runs out at 1 pip or 2 pips, then the problem is with the gas tank and/or gauge. And if it takes out the pump, that's what the warranty is for. Nice thing is if you take it in to be checked out for running out of gas at 1-2 pips then you've got documentation for warranty coverage AFTER the warranty if the pump later fails. So better to learn the reasonable limits while the car is within warranty. Afterall, I paid for an 11.9 gallon tank, expecting some reasonable variability and effective volume below that...but NOT 6 gallons effective.

Does Scangauge show the level indication in something other than pip increments? This would be highly useful if one was concerned about running out. For example, if the gauge "hung" at 25% then one should justifiably be concerned about running out of fuel.

 

In the UK we don't have the bladder, just a regular 45 litre (11.9 U.S. gallon) tank. I generally fill up with two bars showing and the most I've filled so far is 35 litres, meaning the car had 10 litres of fuel still in it, i.e. 22%.

The manual is littered with warning symbols, but the language telling you to fill up before dropping below 25% is pretty clear.

Of course it's possible that the car really has more than 45 litres capacity, but you know what? I don't really want to find out.

 

Australian Prius has a 45 litre no bladder tank. I fill at 2 pips but sometimes it drops to 1 on the way to the sevice station. Most I have put in the tank in one fill is 42 litres.

The only time I have EVER run out of petrol in a car was in a then new Holden Commodore which I drove until the warning of low fuel then 5 more kilometres and even though the gauge said I had 26 kilometres left in the tank it cut out. I was one kilometre from the service station. At the next service the fuel gauge was recalibrated, it was calibrated for a V8 fuel tank rather than the V6 tank.

 

So are you saying you had the wrong tank calibration to start? If so, then this was repairing a defect. If not then you were compensating for the low warning level.

I've had vehicles run out before, just not ones with properly functioning gauges, and none that I've owned from the start. One was a rusting out Chevy hand-me-down that my wife had about 17 years ago. The sender failed, along with the tank itself and the fuel line...it was leaking so much gas that it was a real fire hazard and we had no idea what the level was anymore. (Changed the lot out after identifying the leaks.) One was a Ford half ton 20+ years ago with which I was supposed to pick up some construction material in about 3 miles away. It had 1/4 tank showing...but nobody told me that it had a known defective gauge. It made it two miles, took me awhile to figure out what was wrong. The only other was a brand new Grand Am rental about 12 years ago, ran out at a little over 1/8th tank on the way to the station without triggering warning light, etc. Tank calibration was definitely screwed.

It's because of these sort of surprises that I've determined to make sure I have full working use of my gauges in my new vehicles. None of mine have failed the test so far. The gauges have all worked across their ranges and I've never run out of fuel in one of them with almost every fill below 1/8 tank. That's about 1,000 fills on as best I can tell.

So if someone tries to tell me I should not use the bottom quarter of the indicated tanks, and that the top quarter is also unusable, I've got a real problem with that. A 6 gallon tank is not acceptable for this vehicle.

 

You don't have any idea what is left in it because you haven't tested it. You are guessing. However, with a normal tank this is a fairly safe assumption, not necessarily so with the bladder tank and its "guess gauge." I would gladly saddle you with bladder and use your tank so that you could enjoy this albatross instead and tell us how wonderful it was.

Really, must be the UK manual then because mine says for the flashing pip "Remaining fuel (Approximately 3.0 gal. [11.4 L, 2.5 Imp. gal.] or less)" on page 429 "Essential Information" and to refuel. Now an intelligent reader would take that to mean they should not be terribly concerned that they will run out immediately even at the flashing pip. One would also note that this is ~25% of the tank capacity remaining if the gauge is approximately accurate.

If a gauge can't hit within 25% of empty it isn't worth crap! Heck, I could make a tank that turned on an idiot light at 75% full and only showed you the top quarter, and throw in a manual that gave you all sorts of admonitions about running out of gas, but it would be ridiculously stupid and unreasonable to do that to a customer. Consumers should know better than to put up with this sort of BS.

You don't even know if it has 45 liters of capacity! All you know is that it had 35 once! You have ASSUMED it has 45 liters of capacity. With a normal tank, that's a pretty safe bet.

Now, imagine you have a bladder system that might give you 11.9 gals in perfect conditions (from empty), but will give you ~15% less just due to shrinkage in very cold weather (ironically, when you least want to be standing around pumping gas), and frequently even less since the damned vapor recovery system is so picky about fillsa and often shorts you a gallon or so, seemingly at random.

And for the record, my last fill was in warm enough weather that shrinkage should not have been too bad, it took 8.8 gallons after a few miles on the blinking pip (first time I've allowed it that low.) This was a relatively full fill as shown by an uncharacteristically low calculated MPG vs. MFD. This would appear to be spot on with the manual's statement about 3.0 gallons remaining in an 11.9 gallon tank...but I don't know for sure. However, I do know that if it runs empty when it should be in the neighborhood of 3.0 gallons left per the manufacturer, then there is a manufacturer's defect and it requires repair. Unlike some, I prefer to know about defects and have them repaired under warranty, rather than finding about them in less ideal conditions and out of warranty.

BTW, previous tank at 1 pip = 7.2 gallons in cold weather, while in Summer/Fall 2 pips was filling with ~8.2 gallons. I've been getting 2 pips with about 6 gallons consumed during Winter. Range of half a tank just won't cut it.

 

CAPACITY HAS NOTHING TO DO WITH MPG. got it, loud and clear. however, i've been quite frustrated with the variance involved with the bladder type tank.

STOPPING after the 1st or 2nd click leaves an empty area for approximately 2-3 gallons.

here's my question for you all.

#1) after the 1st or 2nd click, what is your average miles traveled AS THE FIRST PIP DISAPPEARS?

for me, it's 60-80 miles. when i fill up all the way, it's over 150+

this is a huge variance to decipher and shows to be a design flaw.

 

How do you know this? Are you able to add two to three more gallons by topping off, or is this assertion based on calculation?

Tom

 

I was down to two bars so I thought I would fill up, but the tank would only take 2.5 gallons of gas. So i drove home and tried a different gas station near my house and it filled up the entire way.

I believe it has something to do with the gas pumps you use. The one that worked was an older one, the one that didn't was a newer one.

 

I talked about this very issue with Toyota reps at last night's 2010 Prius Event in DC.

The issue has nothing to do with MPG; it's simply the frustration of having to fill-up more often than necessary because the tank doesn't seem to hold a full 11.9 gallons. That combined with the "guess gauge" is the biggest frustration of my 2009 Prius. On Sunday I got a low fuel warning for the first time- I drove about 4 miles to the gas station after the last pip started blinking. I filled up completely, and then pressed the gas pump handle two more times after the automatic stop. This resulted in a fill of 9 gallons- the most I've ever gotten into the tank. (I usually refill at 1 pip left and average 7.5-8 gallons for a fill- consistant across different pumps and gas stations.) The temperature at fill time on Sunday was 59 degrees F if that matters.

The Toyota rep assured me that although the 2010 Prius has the same capacity gas tank the bladder no longer exists and that that issue would no longer occur with the new generation. He also mentioned that the gas guage had been improved. Thats great news; I just wish I could go 10.5-11 gallons between fills with my existing 2009 Prius.

Toyota hosts a very nice event, BTW. I was impressed. It was absolutely amazing at the end of the night when they announced every attendee would be receiving a free 2010 fully loaded Prius.


Just kidding about the free Prius...

 

It is the pumps. The Prius gas tank with the bladder is more difficult to fill than a normal tank, so problems with the pumps and nozzles are more likely to be exposed when filling a Prius. That said, a properly adjusted pump and nozzle will be able to successfully fill a Prius tank without much fuss or bother. The Prius tank bladder is neither necessary nor sufficient for refueling trouble.

Tom