I was filling the old RRC up at the local servo today . When I undid the fuel cap there was a high vacuum in the tank, so much so it "tobacco tinned" when the cap was opened. Its a Long Ranger 140 L.
I had a look at the manual and it seems that this should be correct in that the purge valve stays shut when the car is off, and opens under light throttle which is high vacuum.
My question is whether there is supposed to be a one way valve anywhere to relieve the vacuum? I would think the cap should have this as otherwise it is supposed to be a closed system. It looks like the original cap.
I noted in the manual that some models (USA) had a restictor in the hose from the evap canister to the manifold but that did not seem to apply to the models with the purge valve.
Regards Philip A