Prius Fuel Tank

[tomdeimos]

I have constant shutoffs when I fill starting at as much as 4 gallons from full.

I use the super slow technique, etc to get my tank filled and have had spills. But lately I have been able to fill up spill free.

Here in MA I have found super slow on the pumps also sometimes prevents a shutoff but it varies with the pumps.

My main anti spill techniques are to:

1 fill fast till a click off. Then fill med till click off.
2 Then I can go super slow or just keep letting it click.
3 either way I make sure to pull the nozzle and pause every .2 gal when I know it is near full.
4 I also listen closely and stop and call it full at any kind of sound change.
Sometimes it gurgles, other times it just changes pitch a bit. Either way I stop there.

No spills in the last 5 tanks or so, and it virtually always takes over 10 gallons.
My record was 12.4 about, when I pulled into the station on fumes.

[DaveinOlyWA]

ok i have to say that using my fill technique, i have never spilled a drop of gas. this idea of filling the bladder at low flow creating an over pressure in the system where gas must be expelled like an overweight balloon is preposturous.

if that is the case, one must look at the pump being used as it is has a serious malfunction.

[tomdeimos]

Originally posted by DaveinOlyWA@Oct 12 2005, 08:59 AM
ok i have to say that using my fill technique, i have never spilled a drop of gas. this idea of filling the bladder at low flow creating an over pressure in the system where gas must be expelled like an overweight balloon is preposturous.

if that is the case, one must look at the pump being used as it is has a serious malfunction.

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I agree it is mostly a pump problem, but it is on a whole lot of pumps around here.
The best pumps seem to be the ones that pump slower even at the full speed but these are rare.

As for the spit back I have had it happen with rental cars, where I could care less about trying to fill it full. And these cars had no bladders. I think the only effect of the bladder is it spits back a bit more gas if it happens.

Also a mystery to me is why if I put in just the end of the nozzle and the return holes are outside the filler, the shutoffs often are reduced and I can fill it much easier. Seems like that should increase the tank pressure and make it shut off more often.

[bruceha_2000]

My theory is that the bladder creates more back pressure than the pumps expect so they kick off early. It would be better if there was a sensor that went into the filler pipe and shut off the pump when it became submerged (or some other bizzare method). Don't rely on pressure, rely on actual fill level.
Maybe in the future there will be a sensor in the tank or at the very bottom of the fill pipe that connected with the pump nozzle and would signal "full".
I wouldn't want to try and equalize the pump pressure with bladder pressure, a SURE way to get spit back.

[mikepaul]

I wish the Perma-Cap people had finished a Prius-compatible cap. I'd like to find out if it would hold back gasoline in a bloated-bladder situation...

[Bionic]

I had the same problem as heimdm when I filled up my Prius for the first time yesterday. The pump kept clicking off, even when I was just starting to put gas in. I could get it to go for a bit without clicking on the absolute lowest speed (i.e. right when the gas started flowing) but it would always click off again. Finally I stopped at 7.5 gallons, since I had 3 bars showing when I came in anyway.

I attribute part of this to a new/cold bladder, but it's still a little frustrating, especially since I'd like to be able to manually calculate MPG, requiring accurate fill amounts.

[MNPrius]

Originally posted by Bionic@Nov 21 2005, 12:18 PM
IFinally I stopped at 7.5 gallons, since I had 3 bars showing when I came in anyway.

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Bionic - I've filled up 5 times, with 2 bars showing each time. My average # of gallons has been 7 - 8.8 gallons being the most I got in and 6.1 the least. I'm still tracking MPG on a "manual" basis -- actually a spreadsheet someone had posted.

Filling the car definitely has taken some getting use to!

[LaughingMan]

Originally posted by MNPrius@Nov 21 2005, 09:52 PM
Bionic - I've filled up 5 times, with 2 bars showing each time.  My average # of gallons has been 7 - 8.8 gallons being the most I got in and 6.1 the least.  I'm still tracking MPG on a "manual" basis -- actually a spreadsheet someone had posted.

Filling the car definitely has taken some getting use to! 

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Am I the only one who fills up so infrequently that it feels like a new experience every single time you do it?

[afternoonnap]

Arg, today I overfilled! It happened once before when I was filling very slowly, the pump never shut off.

Today I filled up till it clicked off, using approximately the medium position. It didn't seem like enough fuel, so I let go for one more click. When I drove off, I noticed the top two bars were not lit up, so I went back.

This time I filled up more slowly, and carefully watched the neck to see or hear if it was filling up with fuel. As soon as I saw fuel rising up the neck, I shut off the nozzle and withdrew it, and a moment later a gush of fuel spilled out!

The nozzle didn't make a tight seal, and I could see the fuel rising up, so I wasn't pressurizing the system.

The strange thing is that the fuel gauge doesn't show any higher! Still two bars down, even though I added another 9 litres (approx 2 US gallons).

Outside temperature was -5 C.

[DaveinOlyWA]

Originally posted by afternoonnap@Dec 5 2005, 07:48 PM
Arg, today I overfilled! It happened once before when I was filling very slowly, the pump never shut off.

Today I filled up till it clicked off, using approximately the medium position. It didn't seem like enough fuel, so I let go for one more click. When I drove off, I noticed the top two bars were not lit up, so I went back.

This time I filled up more slowly, and carefully watched the neck to see or hear if it was filling up with fuel. As soon as I saw fuel rising up the neck, I shut off the nozzle and withdrew it, and a moment later a gush of fuel spilled out!

The nozzle didn't make a tight seal, and I could see the fuel rising up, so I wasn't pressurizing the system.

The strange thing is that the fuel gauge doesn't show any higher! Still two bars down, even though I added another 9 litres (approx 2 US gallons).

Outside temperature was -5 C.

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do you have an 04? there was a gas tank fix for early 04's that you might want to check into