Fuel tank vent pipes: 5mm hose

[karmakanix]

I am trying to rid my '82 SC of a mild fuel smell with the windows open. The short 12mm hose from tank to pump was changed a few weeks ago (lucky too, it almost dissolved in my hands!). I have also changed the hoses to and from the expansion chamber next to the fill pipe (15mm and 10mm). I have used Ethanol resistant hoses for all. 

I have some 5mm ID hose for that small hose that runs through the wing from the top of the evaporation tank in the NSF arch but it is a pain to get to and I cannot see the routing. I have attached an image I stole off t'internet as it is better than any picture I could take.

My question regards where this goes. I understand that US cars (or maybe later cars?) this hose will feed under the tank, through the tunnel next to the pedals (I am LHD), to the engine bay or OSR wheel arch to the carbon/charcoal canister then to the intake where any vapour is burnt.

My car is Swiss spec so I wonder if it had this from factory and has been removed (no evidence of the canister in rear) or if EU (+CH) cars had no canister in '82. 

I have a 5mm ID braided hose that runs alongside the wiring from the fuse box to a hole in the front panel behind the bumper but I cannot see if this joins the hose from the wheel arch. It is super tight right there with wiring and hoses - I cannot even see with my inspection camera.

If it vents to the area behind the bumper, why can it not vent in the NSF arch, or could I just run a small evap tank next to the spare wheel to get rid of the water/crud traps in the NSF wheel arch?

many questions but your thoughts would be appreciated

[mean in green]

Have you looked at your fuel filler "swan neck", they're prone to corrosion and was the cause of same symptoms on mine?

[sopor]

There was just an article in Porsche Post about a rusted SC filler neck causing a petrol smell. Will scan it in the next day or two and post it here.

[sopor]

here you go...

[craigt]

I'm pretty sure the pipe your talking about terminates as you say, behind the front bumper. I'll check some pics later.

Check the fuel filler overflow/rainwater drain is in place. It comes out the bottom of the fuel filler in plastic and runs vertically down the inside of the wheel arch to waste.

Also check the seal on the fuel cap?

[karmakanix]

Thanks chaps. The fuel filler neck was new a couple of years ago, it was one of my first projects on this car. The drain is good too. 

I reckon I can simplify the stock set-up and free the wheel arch of those two tanks. 

On 8/10/2019 at 12:52 PM, craigt said:

I'm pretty sure the pipe your talking about terminates as you say, behind the front bumper. I'll check some pics later.

Also check the seal on the fuel cap?

Thanks, I think I am right. I might loosen the fuse box and see what I can see. There are a couple of sketchy wires in there that I can address. Nothing like doing fuel and electrics together. 😬