Newbie w/fueling question

I think it's the overall design of the fuel tank.. The tank contains a bladder inside to control evaporative emissions, but this bladder changes size with temperature and stretches, so the Toyota engineers probably thought they were being clever by putting a tight sealing gasket around the filler.. By sealing in the gas pressure when you start filling, this is *supposed* to help re-inflate the bladder in the tank to maximize its capacity while also reducing the emissions as you fill, but in my experience, a large majority of filling nozzles are quite sensitive to the back pressure created in the tank; it's this back pressure that also results in the splash-back...

I got an X-acto knife and carefully sliced out the gasket and now I never have problems with premature shutoff and never any splashback.. This seems to reduce the variation in fill-up volume for me as well: I drive until the last pip starts to flash and on my car, this means I need 33-35L, and this is quite consistent both summer and winter.. Does that mean that I actually have another 10L in the tank when the last pip starts flashing? Who knows, I've never pushed it very far after the fuel warning, so I can't say.. Perhaps by removing the gasket, I'm not maximizing the capacity of the tank, but on the other hand, if I recall, the most I've ever put in the tank was about 40-41L and that was because I was on the outskirts of the city and couldn't find a Shell station, never mind a "name brand" station to fill up at- I don't trust those independent stations..

 

mine was very slow filling at first, it took about 5 tanks now I can pump it in normally. I think it is the bladder in the tank that is shrinking. mI too use Shell and have found I get more mpg from it and here it cost less.
I think in due time your filling problem will be a thing of the past also dont force more gas into it after it shuts off, I have read here that it can damage the fuel cannister in the system.

 

Hi Vic,

I have had my 07 Prius since December, and a couple of tanks ago I had EXACTLY the same experience you describe.

Many on here will tell you that they have never had the problem, and some will insinuate that YOU are doing something wrong because THEY never had that happen. At any rate, it does happen and there seems to be no certain explanation. The most logical sounding explanation I have seen is that the pump nozzle is oversensitive, either due to wear or defect or whatever.

I believe that's true, but I also believe that the design of the Prius tank, with its tight seal around the nozzle while fueling, contributes to the poblem and may cause this issue with a nozzle that may work fine on another vehicle.

At any rate, it's a real issue but you will see it rarely. I have had it occur just once out of my 10 or so fill-ups.

airliner

 

Ive never been able to get it to the Full mark, at half a tank I fill it up and it still hasnt been able to go back to the F mark, but its new so i figured maybe the tank is doing its job in the heat we have

My dealer did tell me to pump gas at night, since it wont evaporate gas out of the tank anyway

 

In addition to the bladder I'd also say it could be the over-sensitive gas pumps or just the angle/opening in general. The vehicle I traded (04 Tundra) had problems with the pump clicking off unless you held the handle at just the right angle and flow rate but only at certain gas stations. I even noticed that it was certain pumps at some stations and not others.

With my Tundra it was a combination of factors. I've not seen the problem with my Prius but I've only filled it up once so far. We'll see how it goes next tank full

 

I think in our first couple months with the car we had this sort of thing happen about four times, so maybe it is a new gas bladder issue. But I haven't had any trouble with this now since about January (and I find filling the tank faster, as it usually only takes 8.5-10.5 gallons).

 

<div class='quotetop'>QUOTE(Vic Doucette @ May 23 2007, 02:59 AM) [snapback]447991[/snapback]</div>

Well. About 10.5 gallons is the most I've ever gotten in my car. But I still suspect a malfunctioning pump. I've never had a backsplash. After the first time it shuts off, I can usually get another half to three-fourths of a gallon in before I stop. That is with repeat click offs, but I only pull gently on the lever after the first click off.

Dave M.

 

I haven't had a slow pumping experience in my 07 but once it didn't reach the full mark.

Many here refuel at Shell because the gas seems to be giving us better mpg. Good luck

 

While we're on this subject, I've heard references on this site to people having their gas tank spit at them. What's that all about, and how do you avoid it?

And, on the OP, I think the individual gas pump nozzle is the culprit. Some work fine. Some don't.

 

I always fill mine on the fast automatic setting, usually Costco, or Shell. Never had a problem filling it in almost a year and a half, 35,000 miles, filling twice a week. The most I ever put in is about 8 gals, when it clicks off, I stop.

 

<div class='quotetop'>QUOTE(formerVWdriver @ May 23 2007, 02:18 PM) [snapback]448409[/snapback]</div>

The car spits when more gas is pumped (or forced) into the bladder than it can hold. When the nozzle is removed the excess comes back up. My advice is to fill slowly to give trapped air a chance to escape and to stand by the tank. If you hear gurgling the pump's sensor is not going to shut off the pump when it should so stop the pump yourself. Everyone sooner or later will find a bad pump.

 

All of the above responses are wrong. The Prius just doesn't WANT the gas.

rpm

 

<div class='quotetop'>QUOTE(onerpm @ May 24 2007, 10:06 AM) [snapback]449003[/snapback]</div>

If it didn't want the gas it would be an EV only car

In all seriousness I had this happen to me on my second fill, I'm thinking its a combination of the desgin of the tank and the pump your using. In other words its frustrating when it happens but appears to be a normal condition.

On another note I wish we had Shell gas stations out here in the east from all the positive things I hear about their gas...