Fuel tank venting

[jaherne]

Hi all, I'm new to PCGB and have just bought my first Porsche in the flavour of a black 1985 944.
I think I might have a problem with my car that I'm hoping somebody can offer some thoughts on: when I open the filler cap I get a loud 'PSSSHHHHT' as air is either rushing in or rushing out. I think it's air rushing out - It's just like when you open a jerry can full of fuel.

Can somebidy please advise me: does the tank vent through the cap or is there some other arrangement? And any ideas on how I might sort it out? I've got a Haynes manual but it's a USA version and seems to be about useful as a chocolate fireguard. There may be some other problems as it gets a little fumy in the cabin with the windows/sunroof open so I wonder whether it might all be related??

Whilst I'm on, if anybody can recommend a good value specialist in East Kent I'd appreciate it. Many thanks in advance.

 

[Dockrell]

Jaherne,
It's more West Kent but I recommend Project 9 in Marden. They look after my 944 and have always done a very good job at a decent price.

Mike
White 2.7 automatic

 

[jaherne]

Hi Jaherne,

The tank vents via a small bore pipe connected to the filler neck which leads to an expansion tank in the rear quarter panel , and then out through a breather pipe that exits in the boot well behind the rear wheel. There's a one-way valve in the breather pipe which might be your problem. Look here for a diagram:
http://www.porsche.com/uk/accessoriesandservice/porscheservice/originalparts/originalpartscatalogue/

P.S. If you're going in there, work outside and DON'T SMOKE!!! [&:]

 

[Outrun944]

ORIGINAL: jaherne
when I open the filler cap I get a loud 'PSSSHHHHT' as air is either rushing in or rushing out.

Hmmm, I get that after a spirited run and needing to stop for fuel - I thought nothing of it because it only seems to do it when everything's a bit hot. Something to be concerned about or not then?


As for fumes in the cockpit I've had a lot of fun tracing and stopping this. It was really nasty when I first picked up the current 944.
Remember when you open windows/sunroof you're forcing sudden air circulation, often when I just started off and opened the windows I'd get a nasty whiff and then it was fine after.
There's various places to check for holes that could be sucking in fumes, but places to start is usually the boot and making sure the pins and rubber mounts are good and the boot shuts tight. I had a knackered exhaust when I bought this one, the centre box was like Swiss cheese! When I replaced that, the pipes and rear box that made a difference. Also the rubber gaiter around the the gear stick (under the leather cover) - make sure thats nice and air tight too.

 

[jaherne]

Really appreciate your help chaps - it's given me a good start for where to look.
The car's going to Le Mans next month so I'd like to get this sorted before then!

 

[utopia]

I have got the fumes coming in when a window is open, I read a thread on here about checking the bond on the frame to the glass rear screen, mine has been bodged up here and there where it has seperated, just about to book a windscreen specialist to come and re-seal it professionaly, I am hoping that this cures it.

 

[Outrun944]

ORIGINAL: utopia

I have got the fumes coming in when a window is open, I read a thread on here about checking the bond on the frame to the glass rear screen, mine has been bodged up here and there where it has seperated, just about to book a windscreen specialist to come and re-seal it professionaly, I am hoping that this cures it.

Well blow me down, I discovered a couple of weeks ago that one of the pegs had come away on the rear screen (now I know where the clicking noise is coming from when I open the boot!) ... I didn't think that of course this could mean fumes getting in too!

Out of interest .... what windscreen specialist have you booked? And wouldn't your insurance cover this work for you? (I keep meaning to go through and check my policy)

 

[utopia]

I am just going to use a local independent windscreen installer to do mine because it looks a real ball ache to do, I don't think I could really claim on my insurance for the work, going to get the quote next week, hopefully shouldn't be to painfull!