[urq] Fuel tank vent

[craigcook at rogers.com]

--- On Mon, 6/17/13, Keith <spotatashleys at hotmail.com> wrote:

From: Keith <spotatashleys at hotmail.com>
Subject: [urq] Fuel tank vent
To: urq at audifans.com
Date: Monday, June 17, 2013, 1:52 PM

After not being used for a period I get the smell of fuel in the cabin. I’m not losing any fuel but I do have a few questions about the fuel tank vent set up. I have one large braided rubber pipe (about 15-17mm diameter) that runs from an outlet on the top of the tank to the filler neck which I guess allows air to be displaced quickly when filling up. This feels like its integrity is intact and doesn’t show any visual signs of porocity. There is another much smaller pipe that also runs from an outlet on the top of the tank as a braided rubber pipe across to the right hand side and then changes to a smaller bore plastic pipe, does an about turn, runs back across to the left hand side and disappears down behind the tank and I guess exists somewhere below the cabin. I have not yet discovered where it does or should exit (any suggestions?)
My questions though relate to the method of venting. I guess this small pipe is not so much to let air out, but more to let air in to prevent a vacuum being created as the fuel level drops. Is my thinking correct? My family album picture of the tank vent set-up includes a gravity valve. Mine does not have a gravity valve. Did all urqs (mine is a WR) have a gravity valve and so should mine have one? As the part is NLA will one off a VW Polo do the job? (I guess the gravity valve should allow air in and stop fumes – and fuel if the car was inverted! – from getting out).  So there’s a few questions there. If you can answer any I will be most grateful.
Many thanks

Keith

‘87 WR
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