Interesting fuel issue, 2016 Three Touring overflowing

Look for the label on the inside of the gas cap door. In the USA there is a warning sticker that says you only have 30 minutes to fill up...

 

I think there was a TOPIC on oddities - but can't spot it now. It was quite long from memory.

 

Or, there may be hundreds of others with the same problem, and we'll never know about it because not everybody reads or posts on a internet car forum.

I like my Prius. The main good thing is the excellent gas mileage. But man, it sure has a lot of "odd anomalies." Since it's my first hybrid, I expected it to be a little different… But I sure didn't expect it to be weird and strange in so many ways.

 

I can't see it there.

 

I've never heard a "whoosh" sound when removing the gas cap. And I always fill the tank to the point of overflowing. The more petrol you can squeeze in there, the better gas mileage!

 

This vehicle vents the tank when you press the button to open the fuel door lid. That is why you don't hear anything.

Also, best practice is NOT to fill past the first click. Overfilling the tank can damage the evaporative emissions system.

 

Roger that. Thanks.

 

How does it do that? The gas cap surly does not unscrew itself. Is there a one way release valve somewhere?

 

Probably something involved, especially considering it's on a timer. But gas caps have had rudimentary venting mechanisms, for decades.

 

Best place to learn about the details is at techinfo.toyota.com in the new car features manual. Please note that this system is why it says "refuel ready" on your MID after you press the release button.

• When the vehicle is parked (with engine stopped), the system closes the fuel vapor-containment valve (fuel tank solenoid main valve assembly) to seal the fuel tank assembly.
• For refueling, the system opens the fuel vapor-containment valve (fuel tank solenoid main valve assembly), allowing the fuel vapors to be absorbed by the canister and reducing the pressure in the fuel tank assembly.
• When the engine is operating, the system controls the fuel vapor-containment valve (fuel tank solenoid main valve assembly) to release the fuel vapors and perform purge flow control.

Indication on Multi information display


"Please Wait Now Opening" - This is the standby state that occurs while the pressure is being released from the fuel tank assembly appears on the display under the following conditions:

• The fuel lid opener switch was operated and the fuel vapor-containment valve (fuel tank solenoid main valve assembly) is open.
• The internal pressure of the fuel tank assembly is higher than atmospheric pressure.

"Refuel Ready" - This is the refueling-ready state appears on the display under the following conditions:

• The fuel vapor-containment valve (fuel tank solenoid main valve assembly) is on.
• The internal pressure of the fuel tank assembly is near atmospheric pressure.

"Close Fuel Lid"- If one of the conditions described below has been met while the fuel lid is open, the fuel lid open state message appears on the display.

• The vehicle speed is higher than 50 km/h (31 mph).
• The vehicle has traveled more than 1 km (0.6 mile).
• 30 minutes have elapsed since the fuel vapor-containment valve (fuel tank solenoid main valve assembly) was opened.

 

There must be something timer based. I am sure you have seen the warnings on the fuel door & manual that you need to either finish refueling within 30 minutes or press the "door open" button again.

 

I have not seen those messages on Gen 4 Prius but there is a warning on the fuel door stating that you need to finish refueling within 30 minutes or press the button again. If you do not, fuel may overflow.
IOW, your posting does not apply to the gen 4 thread you posted in.

 

Note that US/Canada destined vehicles and those for other countries will have different specifications for the evap emission systems. I would not expect this system on an Australian Prius.

 

I realize this is an old thread, but some who commented here might be interested to learn that Toyota has issued a service bulletin for the U.S. market, T-SB-0220-17, for one possible cause of the overflowing problem. I’ve written more about this in another thread.