2008 Prius, bought at 100K miles 2 years ago, now with 120K miles. We've always (always) had to trickle the gas in to fill it. I recently sent a borescope down, and the fill tube is wide open all the way down. That got me reading about the ORVR system. I speculated the previous owner topped it up and fouled the charcoal filter. I got below the vehicle and released some of the tubes going in and out of the various "charcoal filters." (I put that in quotation marks because I'm not 100% that is their function.) I blew compressed air through them without difficulty. I then reconnected all the hoses except the one that I think is the fresh hose inlet, then I went to refuel. I wanted to know if the car would sense an EVAP system fault. It did not (in the ~10 mile journey, anyway). For the first time ever, I was able to refuel at full nozzle speed--BUT ONLY IF I "BURPED" THE NOZZLE'S VAPOR BARRIER RUBBER JUST A LITTLE BIT (we live in California). I didn't fill it all the way up, because I wanted to show my daughter the 'trick.' I probably put five gallons in (and I was down to a single pip). Interestingly, the fuel gauge never rose. The next day I went with my daughter to show her the trick. As a test, I reconnected the fresh hose inlet (underneath the car), and now the so-called 'burping trick' didn't work anymore. (And that reminds me that of course we had tried burping the gas station's vapor recovery "cap" over the last two years without any improvement, so it is obvious (now) that the trick relies on the disconnection of the fresh hose inlet.) So, now I have more questions than answers. First: can anybody make sense of why I can refuel at normal rates when both the "fresh hose inlet" is disconnected under the car AND the gas station's vapor recovery cap is burped? Second: Will I eventually throw an EVAP system code? Third: which is worse for the environment: venting my fresh air inlet to the atmosphere underneath the car, or burping the gas station's recovery cap? Fourth: is the air hose I disconnected (pictured below) actually the fresh hose inlet?? Fifth: Is it a coincidence that with the fresh air inlet hose disconnected, I had to recalibrate the fuel gauge sensor before it would recognize that I had refueled the car (I had put in ~8 gallons, and the gauge still read only a single pip. After the recalibration, it now reads full.) (I'm sure I'll have more questions. I thank the contributors for sharing their wisdom, experience, and advice.)
