Hi, some of you may remember I had a fuel supply issue which was fixed with the addition of a one way valve stopping back draining probably due to an air leak in the non Ford primer pump/filter assembly.

Just recently, I've been having a few starting problems and noticed a large inrush of air when removing the filler cap, so obviously a vacuum is being set up.

In my last thread, it was suggested that the vent pipe mentioned in the Haynes manual was to allow air to vent outwards when filling with diesel. and that the red banded filler cap was vented to allow air in when running.

(I would have thought that the first vent I mentioed would vent in either direction anyway.

Any thoughts anyone on how/why the vacuum is being set up ?

Many thanks................ebt