Pressure in Fuel Tank 2

[willy mussell]

I know this isn't the most thrilling topic going, but I'd really appreciate a quick response, just to put my mind at rest.

Is it normal for there to be a pressure build up in the fuel tank?????

Cheers in advance.

[alt]

When I take the fuel cap off air does escape but only for a second or so.
Nothing I've ever worried about......

[dicky]

i always get some kind of whooosh especially when really low, but like Andy never worried about it.

[scotti]

I get a small "whoosh" sort of sound when I undo my petrol cap. Happened on my previous car as well so I don't think it is anything major. Never lasted 15 secs as you mention in your previous post.

Re: smell of petrol, I've never had it but I did read in the paper this weekend that in this hot weather, fuel tanks can expand and leak a little. Not sure if that happens to TVR's but it may be the reason for the smell.

Cheers,
Iain

[willy mussell]

thanks alot guys.

as i first thought, seems like the whoosh is perfectly normal then.

any of you mechanically minded people got an expaination re. the breather pipe though????

thanks,
Will

scotti - thanks for your advice, i'll see what happens when the weather cools down

>> Edited by willy mussell on Wednesday 13th August 14:05

[nubbin]

It's all normal - the whoosh is pressurised petrol vapour escaping, which is why it's worse on hot days, and when the tank is full-ish.

What amazes me is the fact that, once you break the seal on the petrol tank, where the filler pipe is screwed on, it always smels of petrol - you can never re-seal it properly!

[RichB]

willy mussell said:

...any of you mechanically minded people got an expaination...

I think it is because the fuel pump provides petrol from the tank to to the injectors at a pressure in excess of their requirements, any excess fuel is then returned in a closed loop back to the tank. I always assumed it was the build-up of pressure caused by the fuel pump effectivly pumping up the tank? Rich...