1989 XJ40 fuel tank vacuum canister

Over the years I’ve been plagued with an intermittent fuel smell in the trunk and in the cabin. It doesn’t bother me that much (well maybe a little) but my wife goes into her high drama mode … grabbing her throat and rolling out of the the car gasping for air (but actually she does have a great sense of humor :grinning:).

I’ve pulled the tank out twice over the years and it’s been in perfect condition. Not a trace of corrosion on the outside and nothing I can see on the inside with a long borescope. Both times though it appeared there was a very small stain around the top hat … On my '89 with the external fuel pump the fuel tank has a small metal dome on the top, fittingly called the … top hat

Both times I’ve removed the tank and had the area around the “top hat” resoldered with good results …
temporarily .

SO THE QUESTION BEING … is anyone familiar with my fuel tank vent system and how it actually works? The charcoal canister has several check valves and is vacuum actuated, but before I get down and dirty with it I wonder if anyone has already been there.

Again remember it’s an '89 with an external fuel pump.

The purpose of the purge valve is to redirect the fuel vapors from the tank to the intake instead of releasing it into the air. I just replaced the electrically operated one. I’m gonna replace the other one too, the vacuum type. The day before I changed the valve, my car ran so badly that pushing the gas pedal made the car go slower. That was in the morning when I went to work. The engine also stopped on the main road while idling. I guess the vent pipe from the tank goes directly to the charcoal canister then the vapors go through the two valves before entering the inlet.