gushing gas fillup overflow

Congratulations on your recent purchase.

If you wait until only one blinking pip shows on the fuel gauge before refueling, I suggest that you stop after you've added 9 gallons. After you stop pumping, wait a few seconds before you withdraw the nozzle. Also note that some owners who wait for the blinking pip have been unpleasantly surprised by an out-of-gas situation since the gauge may not provide repeatable results.

Good luck.

 

I have a thoery here and others may chime in on it.... here goes.

I notice you live in a very cold climate. The gas tank has a rubberized bladder in it, whose purpose is to minimize the volume of air above the fuel as the tank drains. Toyota decided to do this to reduce the hydrocarbon vapor and the chance of pollutants in the atmosphere. As you well know, rubber doesn't flex real well when it is very cold. I believe the tank is topping off quickly and later burps and chugs as the bladder flexes and relaxes very slowly due to its stiffness.

My suggestion to you and everyone else who lives in a very cold climate: If you have a garage, you're naturally going to park your Pri there, but if you need gas, go first thing in the morning or right after you take it out of the garage. Hopefully, the bladder will be a bit more supple and you'll get more gas in a bunch easier.

I never experience this phenomenon here where our nighttime temps are upper 50s and the coldest it ever gets in the winter is 36 or so.

 

Many have had the gushing syndrome. I'm thinking it's caused in part by slow filling. So I've started filling at full thrust. When the pump clicks off, I have filled more slowly and added a half gallon or so additional. But I also have found that the variation beteen MFD mpg and hand-calculated mpg is wide. So I've just started ending the fill at the first click. A few tests more to run, but the first try had the hand-calculated mpg only about .6 gallon above the MFD figure.

 

A quick comment on MFD mileage vs hand calculated mileage. Because of the bladder tank, you never know from tank to tank how full the tank really is. The only way to ascertain the true MPG is by calculating over several tanks of gas by dividing the total miles driven by the total amount of gas purchased. If your hand calculation agrees with the MFD for a given tank, you just got lucky on that tank. As the Prius is so good on gas a small inaccuracy in how much gas was burned on a given tank can cause the hand calculated mileage on a single tank to vary over a wide range. It has been discussed in many threads that the MFD reading is usually within a mile per gallon or two of the true mileage. The car knows with pretty good accuracy how far its traveled and how much gas it has injected into the cylinders.

Watch the MFD display as you drive and calculate your mileage over several tankfuls. Most important enjoy driving the car!

 

By continuing to fill after the click off, you are pressurizing the bladder. Once you pull out the nozzle, the pressure from the bladder pushes fuel back out the filler neck. How do you avoid this? It's simple: don't overfill. When the pump clicks off, you are done. That's it. The Prius has a small gas tank, and you are never really sure how much will go in. Don't make any assumptions and you will be a lot happier when refilling.

Tom

 

We have a little more to our filling issue. Our 04 Prius started with the gushing overflow, but then became the 'I'm not taking more than a few ounces at a time' problem. It became so bad that the only solution was to replace the tank. That solved the issue for months; however, it now seems to be back. Comments/Suggestions?

 

Lots of threads about the gas issue with the Prius. Everyone has a theory on what to do or what not to do. Most agree and some do not:

1) Slow flow the fuel input. If you do it automatic, set it on the slowest flow.
2) Don't fill anymore once it clicks off. Topping off = gas on foot (not in every case)
3) Some pull the nozzle back a little instead of deep throating it.
4) Some are convinced that turning the nozzle upside down is the key.

There are multiple threads on this issue and here is one you can peruse.

http://priuschat.com/forums/knowled...ank-filling-up-issues.html?highlight=gas+tank

 

This is normal for the Prius. The fuel bladder design sucks and will cause you problems on and off for the life of the vehicle. In my experience there is no rhyme or reason to when the bladder will spit gas on you. I've had it happen hot, cold, topping off, or on the auto shut off. It sucks but is just part of the Prius ownership experience. Toyota denies that this is a problem and has no solution.

 

I did a little look and found this that might shed some light on how the tank is designed and such.

http://www.autoshop101.com/forms/Hybrid13.pdf

 

[quote=ma2288;744992]First, let me thank everyone for this forum. I am a new Prius owner, 2009 pkg #6 non touring...two weeks / 2000 miles, and this forum is priceless. I have searched this forum for my issue / problem and see others with it but not really a definitive answer / solution. I have driven each tank full to 1 blinking pip and then driven maybe an additional 15 - 20 miles. Each fillup was at a different station but all acted the same. It would "auto" fill with the slowest click on the gas handle and it would auto shut off at between 4 and 5 gallon.

From the link;
The inclinimeter must be reset if the customer complains they can only fill 4 gallons at a time,...

inclinometer recalibration techn. ( Fuel Gauge Calibration Instructions)
If these aren't the same, I'm sure someone will advise, also why Toyota acts is if this is some 'dealership only' secret annoys me, anyway..
from a search;
"from rick57 over on the old site:

Ok .......... Here is the steps from the TSB and only applies to the 2G.

1. Park the vehicle so as it is level,front to back and side to side.
2. IgOn and make sure that "Trip A " is showing on the odo ( this is where we made a mistake Embarassed ).
3. Power down.
4. Keep your foot off the brake.
5. Push in and hold down the Odo/Trip button.
6. Push the Power button twice to IgOn ( not Ready mode ).
7. Turn the Odo/Trip off then On 3 times in 5 seconds.
8. Continue holding the Odo/Trip button until a 6 digit code appears.
9. Release,then push again the Odo/Trip button for another 5 seconds. The 6 digit code will change to a 5 digit code.
10. After the middle digit,of the 5 digit code,changes to "1" release the Odo/Trip button and the odometer will return to normal reading.

Hope this clarifies the steps.

_________________
Rick Angles
Toyota Master Diagnostic Technician
Toyota Hybrid Technician"


End quote. Let us know if this helps. Also, for my 04, it really has cut back to about to 9 gallons estimated total fill level now that it's around 30 degrees , I haven't ran it dry and don't want to. The one time my 04 'gushed' once once I was overfilling and added about 1.7 gallons extra, now if I want to push the range I'll only add up to a gallon and haven't had a problem.

 

After you fill it to about 10 gallons total, give it some time to let the air escape. If when you take the nozzle out it starts to overflow, put the nozzle back in & let the air escape from the overflow hole. Then fill slowly letting the air escape while filling the bladder. First time this happened to me it was quite a surprise.

 

If it is gushing like this in relatively cool weather then the interstitial space between the tank shell and bladder must be pressurized and not venting as they are supposed to. (I wonder if there is a way to make a manual bleed check for that space?)

Flashing of the fuel will not be an issue in cold weather. I suppose it is possible that the air being pulled in through the pump nozzle's venturi is filling some fold in the tank so that the pressure is in the bladder instead and forces liquid back up the tube as soon as the pump pressure is shut off. Either way, it is a problem with the way the vent system is set up or operating.

 

I agree with ma2288...I started refueling at one half empty and with initial burping and slow filling I have much less problem.
Isn't it nice when this is our biggest problem?

 

You are spot on with what I am going to say! I *HATE* the fuel bladder design. Sometimes you just look like an idiot when filling up the tank.

Usually, before I re-fuel, I do calculate how much gas is used and try to fill up the amount. And yes, usually the first few liters are real PITA to fill, it just click so many times, and sometimes no matter how lightly you pull the trigger or have the nozzle almost all the way out....

And now it is winter, and somehow I just feel Prius is not a very good winter car (with other problems/issues I have already experience)