High Pressure created in fuel tank

Hi

I orignally posted the following question about tank pressure building up which is released when I undo the fuel cap.  see post:-

http://www.vwgolfmk1.org.uk/modules.php?name=Forums&file=viewtopic&t=1812&postdays=0&postorder=asc&start=10

If you read posts you can see GIT has a very similar prob.

I was happy to hear that it was normal but I always thought the vacuum created in the tank was too high.  Anyway the other day I drove out to the country to give a mate a lift and when we stopped the car would not start again.  It ran really well before we stopped.  Anyway we tried to bump start it but the engine would not fire at all (fuel starvation).  We waited for it to cool and checked what we could still nothing.  I then thought about the pressure in the tank and opened the fuel cap and released the pressure, guess what it started first turn of the key.

Is it possible that the pressure was stopping the fuel pump from spinning.  I have had a look at the breather pipe from the filler neck and it doesnot seem blocked, have not traced all of it but when I blow down it sounds like the one way flap in tank shuts and the air ruches back out of the pipe.  Also checked regulator tucked above filler neck and seems to work.  Cannot seem to find the other regulators as described in the haynes manaul.  Anyway if anyone has any ideas then please do I am completely stumped.

Thanks in advance.

Cussco

sounds like youve got a bolcked pipe somewhere!!!!!!!!!

pressure wil help push the fuel out whereas a depression/vacuum will stop the fuel bieng drawn out!!

I always thought that the tank was under slight pressure…..

See Fuel tank here:
http://www.ford-capri.…k/whiterose/Injection.htm

Fuel tank should be under pressure. Stabbing in the dark, but could be crud in the tank blocking up fuel takeup, pipes etc. When you release the cap the presuure release could temporarly free the bits and pieces until they get sucked up again by the pump :dontknow:

Cheers

Long debate over the tank being pressurised or under vaccum before.  Either way breather system sounds blocked on some way

Hello ,
I had the same problem with my car in building excessive pressure so I
changed the breather valve with is fitted and hidden away under the inner wheel arch liner by the filler neck. It is a good chance the valve is stuck and not working. Approx ?30 from VW

Hope this helps