Problems pumping gas

<div class='quotetop'>QUOTE(tlmkr7 @ Oct 5 2007, 09:21 PM) [snapback]522032[/snapback]</div>

This makes no sense whatsoever. If it takes pump pressure to expand the bladder, then creating an air gap would cause fuel to rush out of the air gap instead of expanding the bladder. This is another example of dealers talking nonsense.

As for how pumps are adjusted, MOST is a gross exaggeration. A few pumps may be mis-adjusted, but certainly not most. I have occasionally run into pumps that don't shut off properly when filling my other car, but so far have never had a problem filling the Prius.

Tom

 

<div class='quotetop'>QUOTE(tlmkr7 @ Oct 5 2007, 09:21 PM) [snapback]522032[/snapback]</div>

This makes no sense whatsoever. If it takes pump pressure to expand the bladder, then creating an air gap would cause fuel to rush out of the air gap instead of expanding the bladder. This is another example of dealers talking nonsense.

As for how pumps are adjusted, MOST is a gross exaggeration. A few pumps may be mis-adjusted, but certainly not most. I have occasionally run into pumps that don't shut off properly when filling my other car, but so far have never had a problem filling the Prius.

EDIT - Sorry about the double post: PC is doing some very odd things tonight.

Tom

 

<div class='quotetop'>QUOTE(qbee42 @ Oct 17 2007, 05:23 PM) [snapback]527141[/snapback]</div>

On the contrary, it may make sense. In order for air or gasoline to be pushed out of the bladder, the contracting pressure of the bladder has to exceed the force of gravity on the the air or gasoline. Since air is lighter than gasoline, it can be pushed out with less contracting bladder pressure than gasoline would. I imagine you could do a practical experiment on this using a balloon with water, air, and water+air as a reality check.

The reason I say it may make sense is b/c it depends on the implementation on the air hole used for fuel shut-off. This is how the fuel shut-off works: http://www.pa.msu.edu/sciencet/ask_st/122591.html I imagine that the source end of the hole is attached to the flexible bladder somewhere and since it isn't a rigid object, it's possible for it to drop below the gasoline level when there is an air pocket. This would cause the fuel shut-off to kick-off so the bladder does not get filled completely with gasoline (though the bladder is full from gasoline + air). In this case, pumping more gas is unsafe. You should just wait until the next fillup to put in more gas as the air pocket can probably be cleared by movement (driving around) or higher temperatures (allowing the bladder to expand more easily).

 

I just re-fueled my '08 Prius for the first time. The nozzle shut itself off constantly. The only way I got gas to flow was to exert the very slightest pressure possible. I thought the problem might be with that particular pump so I stopped after I finally got 5.6 gallons in. Then I went to a different pump but it worked exactly the same way.

I wanted to fill the tank to get an accurate calculation of my mpg. But with pumping at such a low flow rate I knew that the automatic shut-off would probably not work. [I read lots of PriusChats that warn against over-filling the tank.] So I guestimated that around 8 gallons would get the tank pretty near to full.

I know this thread seems to have stopped last October but I wanted to let others know that the problem still exists with 2008 models. Next time I'll try "pushing down on the pump nozzle" as was suggested by tlmkr7.

 

I don't think the Prius tank has an air relief like other cars. If you notice the gas nozzle fits in our prius's very tight and I think there is a rubber gasket there to make sure it is tight. If there is no air relief hole then the quicker you pump (if it will let you) the more air you are compressing and that is when you will get that gas tank puking like in the exorcest movie. Go find a Buick or something and look at the filler, there is the place to put the nozzle and around it you will see plenty of room for the air to escape the tank as gas is pumped in.

 

I don't see it as a problem. Look for a working pump. The Prius is designed to keep fuel vapor from leaking into the atmosphere when refueling, so it does confuse some mis-adjusted pumps, but that is a gas station problem, not a problem with the Prius, so I wouldn't expect it to get "fixed".

Tom

 

I have a 07 model and have had it since last February. I have always filled up with two or three pips showing and have never had a problem. However, when I filled up last week, I did it when the gage still showed half full. The reason that I did not wait till it was down to two pips was because we had a couple of warm days and it was more pleasant to fill up then than to have to do it when it is cold and windy.

I always put the nozzle in all the way and set it for the slowest fill. Well this time it clicked off instantly and did so every time I tried to re-start it. I knew that I had to put in at least three gallons so I pulled the nozzle almost all the way out and held it so that it could vent. I put in a little over four gallons and stopped.

The gage moved up to full, but the first pip went away after about 50 miles, so it could have held a little more.

I will wait till it is down to two pips before the next fill-up and see how it behaves then.

 

I have a 2004 and periodically I will have a similar problem. I have managed to pump gas at the normal rate after doing one or more of the following:

o repositioning the nozzle e.g., pulling it part way out, or twisting it in the opening, etc.; and
o rocking the car up and down a few times.

I have also had a problem with it stopping BEFORE it is full (maybe 1 - 2 gals short of full). I usually rock the car up and down a few times (I figure to release any trapped air in the tank/piping).

 

A similar thing happened last night when I went to refill my new '08 Prius for the first time. I was down to one pip. I had a $25 gas card at Shell, but figuring that wouldn't be quite enough to fill up the tank, I wanted to give the gas attendant an additional $10 so that I'd have $35 worth of credit on the pump before starting. Unfortunately, he said I'd have to first pump the $25 gas card amount, then put the nozzle back, and then he could let me do an additional amount as needed (I guess that's the way their computers are set up).

Anyway, after pumping the initial $25 worth, I had put in about 7.5 gallons. The pump never stopped once until it clicked off at exactly $25. I was sure it could have taken more, so I gave the attendant the extra cash and proceeded to try to pump the additional gallon or two that I assumed were needed to bring the car up to full. But as soon as I started to resume pumping, the nozzle kept clicking off. I did this a few times before stopping, only managing an extra .15 gallons. Nothing ever spurted back out at me, but I wasn't able to resume pumping any additional gas.

It seems that after the initial 7.5 gallons, the tank was close enough to full where it would not accept any additional gas, even though if I had not had to stop in the middle, I think it probably would have happily taken a little more before clicking off the first time.

Interestingly, even after having been down to one pip, and putting in barely more than 7.5 gallons, my fuel gauge now reads a full 10 pips. So I'm happy. Only problem is my calculated mileage for the first tank was probably too high, as I'm guessing I probably used more than 7.5 gallons off the initial tank.

Unless, I really started with a lot less than 11.9 gallons, as a result of the bladder being contracted due to winter weather.

 

You'll get fewer miles than usual before that 10th pip disappears. If I'm down to 1 pip, most pumps knock off at about 8 gallons. Since I know my MFD is about 2% high, I can easily calculate how much I have really used and put that much in. More often than not, especially in winter (Vermont winter, not L.A. winter ), I need to pull the nozzle out a fair bit so the back pressure doesn't cause the pump to shut off early. It is unfortunate that the pumps can't differentiate between a Prius fuel bladder back pressure and a standard tank 'the gas is coming up the pipe' back pressure.

 

Ok, I have read the entire thread, and I firmly believe that the problem is air, and those of you that commented on the lack of air relief are on the right track.

I have the same problem with my 06, and have had from day 1. I fuel up at the gas pump, and the pump clicks off when I know it should have couple of gallons to go, I remove the pump, wait a bit, and get the geyser of gas. Some times more, sometimes not at all. I began listening carefully for the sound of gas going into the tank changes pitch when it reaches the point where you are going to get your gas bath. If I keep the pump in, then gas oozes up around the pump and flows out, down the paint on the car, onto the ground. With much practice, I learned where to stop, and wait, and then pump more slowly, and avoid the waste of gas.

I have observed that gas going into the tank contains alot of air-bubbles. I think more at some stations, less than others. I believe these air-bubbles are the problem.

I have a bunch of gas cans at home that were used to store gas for a small tractor and other vehicles. So anyway, focus on the 6 gallon cans, I take a funnel and it fits perfectly into the gas hole in the Prius, and simply pour the contents of the 6 gallon gas can into the funnel. The gas goes in without the airbubbles that come from the gas at the pump. There is no geyser, no gas spitting back, and nothing anything like it at all. Filling the Prius is like filling another gas can. It goes in smoothly, and when the tank gets near full, the rate at which the gas drains from the funnel drastically slows, and so I stop feeding the funnel, and then remove the funnel, and I know it is full. I may not see gas, but if I try to add more, I will, and will see it sitting in the filler neck, in other words that would be topping off the tank. No gas is spilt, no mess, no gas baths.

In summary, fill at the station where I see small bubbles in the gas stream being pumped in, and I risk the bath of gas. Fill out of a can where there is no bubbles, and it simply fills the tank without the risk of the mess.

 

Air in the gas:
I filled up a guys cruiser, he had diesal tanks, with diesal, and unknown to me, some bug had clogged his air relief vent. Well, the nozzle clicked off, I heard a bubbleing and so I removed the nozzle to listen, and then after half-a-minute, I got a geyser of diesal rushing out of the filler hole in the deck which covered me and the whole side of his cruiser with diesal fuel. It was a mess. Weeks later, the owner told me that he cleaned out his air releif vents, and never had any further problems when refueling.

I am not sure how the fuel nozzle on the pump works, exactly. I am therorizing that air is introduced into the stream purposefully, something haveing to do with giving the nozzle the ability to sense when the tank is full so that it can shut off automatically.

 

11.9 gals. 10 pips. when i get to last pip and it starts blinking, 350 to 400 mi on that tank, it only takes 8.9 or 9 gals till the pump clicks off. the mpg overall says 48+ X 11.9=???
is there still 2.9 or 3 gals in there?
or am i really near empty and the tank for some reason won't take any more?


and what's with 'find a pump that works'? i'm driving cross country, i want to go at least 500 mi and then use any pump i can get to. this doesn't seem anything like unreasonable. 'find a pump that works' seems both unreasonable and stupid.

 

I filled my '08 up for the 2nd time last night. Like the 1st time, I could not get the handle squeezed even the slightest bit without the nozzle clicking off. I pulled the nozzel out almost all the way and was able to apply only slight pressure before it ckicked off. It took forever to pump 9 gallons in bitter cold with wind. Not fun. My wife is afraid to pump gas. (it is her car) There are many theories on this thread. I'm not saying anyone here is right or wrong, just that there is not a common solution coming out. Sounds like Toyota has a problem with this model. I'm going to call my dealer and talk to the service department. I'll let you all know what they say. Hopefully they won't add more confusion to the problem.

 

ok dharma, looking forward to seeing what they say. i will also call my guys here in SE Houston in next couple hours and compare notes with you after.
thanks.

 

Called the dealer and talked to a service tech. He said he remembers a Prius with the same problem last year sometime and it filled OK at the dealer and a station close by but when they took it to another station it clicked off with little pressure on the handle. He does not know what the solution was, but will look it up till I bring my car in when the gas tank is at most 1/3 full. I'll be back here with my findings in about a week. Stay tuned.

 

Newer gas pumps have a pressure sensor to tell it when to "click off". In older cars--like my 1992 Volvo--this would happen if the nozzle were angled a bit "off center" in the fill tube. I have had this happen more times than not when filling my Prius locally in the Buffalo area. I still have it happen with my 1989 Volvo as well--just not as often but I don't fill it until it is nearly running on fumes. We have several Native American gasoline "meccas" locally that don't charge state gas taxes. Their pumps sometimes are older. Clicking-off too soon doesn't happen as much there for either car.
The pressure click-off occurs sometimes just because there are more people pumping who are "topping off" their tanks and creating pressure surges in the pump system as a whole. I think the clicking with the sensor may happen a little more frequently in the Prius due to its bladder tank. As for knowing how much to buy, I just watch the mileage-know my mpg for the weather conditions and fill accordingly.

I have a 2006 and this is my second Prius (traded the first for the tax credit in '06 to have a two-year newer car with essentially a wash on the purchase price through the tax credit). I'm on the road a lot--in NY and PA and the "clicking problem" really seems to be a function of the pumps and their safety settings for pressure. Older pumps without that feature don't tend to do it as much.

 

Hello!

This is my first post on PC, but I had read this thread prior to buying our '08 Prius. Filled up for the first time today, and yep this happened to me as well. I did try to fill up slowly, but didn't seem to help. I sure wish there seemed to be a clear-cut solution. I'm planning on making a cross-country trip with my 13-month old daughter in 3 weeks, not looking forward to this little quirk the whole way.

 

Today I tried a slight pressure down on the nozzle while filling, it seemed to work. I did not stick the nozzle in all the way in also. I will try this again on the next fill up and see if I was just lucky today.

 

I filled up several times since my last post on 2/1 and had no trouble with any of the fill ups. Don't know what's different. I even went to a pump that I had trouble with and it worked fine.