I've noticed in the workshop manual it lists this as a "fault". How much pressure build up is a problem?

When I take my fuel cap off to refill there is often a hiss - usually only if it is a fairy empty tank. Only once was the pressure very strong - and it even blew the fuel cap out of my hand with its force as I went to remove it (normally it is just the slight hiss, though).

Is this normal pressure I am experiencing, or definately something bad?

Kim

One way u can tell is if you light a match near the cap when opening it and measure it by the size of the bang.. little bang means small prob and big bang means small fault..

U will need fire proof under wear to take out this test..
Good luck

Thanks, I'll give that a go. Will let you know the results.

F*@%K!!! What kind of advice was that????

Look at my car now:

http://www.steamboatfire.com/photo_album/photos/car.jpg

lol omg......look what you've done. hope that easy 2 fix. lol .

i have the same sorta pressure release when filling up. so it actually could b a problem???

yeah i should be able to fix it with a bit of cut and polish lol

I always thought the slight pressure build-up was normal - was only when I read it in the workshop manual under the "faults/diagnosis" bit. Maybe slight pressure is normal? Does anyone else notice this same thing?

Yeah i get the same thing, hissing escape of air noise when i take of the cap. Normally more noticible when close to empty (i reackon its more to do with how long since it was last opened as oposed to how much fuel is left).

ok, sounds like its nothing unusual then...

Cheers,
Kim

Nope i get it too, but never tried the match test..

Thanks, i know i wont try it now..

it is perfectly normal especially on a warm day, which you would not get in tassie :bowrofl:

Serously though there is a one way valve that in near the carbon canister from memory, check this is working ok as they tend to get jammed.

The hiss is totally normal. It's not just mitsy's that do it. Heaps of cars do it. You will find if your cap is tight and you wait till your on empty and have had it on for a full tank the hiss will be bigger. If you find that after you fill up and you get home, if you try it and it makes the same loud hiss, the valve may not be working properly. But don't stress it is normal, as others have stated. :D

My mums skyline does the same thing. I have always wondered if its something to worry about.

yeah my ts also does it...mates VT does it aswell

yeah mine has a pretty radical noise too

it is perfectly normal especially on a warm day, which you would not get in tassie :bowrofl:

Serously though there is a one way valve that in near the carbon canister from memory, check this is working ok as they tend to get jammed.

all petrol cars sold in australia since 1975 have an evaporation control system on the fuel tank breathers, the charcoal canister is part of this. The system is designed to allow the tank to draw air in as the fuel level drops but is also designed to seal the tank and prevent fuel vapour escaping as pressure builds like when parked on a hot day. But only up to a certain pressure. If the pressure builds beyond this relief valve setting then the vapour is released into the charcoal canaster which absorbs the vapour, or on some older cars it's vented to the air filter housing. the vapour is then drawn into the motor the next time the car is started and burnt.

So fuel tanks are supposed to build pressure but not too much, if it does build up excess pressure check the one way valve as Madmagna suggested.

Mine does it too. Next time you are at the local servo have a listen to all the other car's when they come in....some ****ty van made a 'pssshhhht-faaart' sound last time I was filling up. OMG I larfed so hard all the way out of the servo.

Mine does it too. Next time you are at the local servo have a listen to all the other car's when they come in....some ****ty van made a 'pssshhhht-faaart' sound last time I was filling up. OMG I larfed so hard all the way out of the servo.
ha ha ha

F*@%K!!! What kind of advice was that????

Look at my car now:

http://www.steamboatfire.com/photo_album/photos/car.jpg

that'll buff right out

Mine will always do it, the emptier the tank, the worse. cheers!