Now that the summer heat is on here in Florida, I have noticed my fuel tank pressurizing. Most noticeable by an occasional banging sound coming from the boot area when driving. When I open the fuel door after the car is sitting in the sun, a large whoosh comes out and you can hear the fuel tank crumple.

I'd like to address this issue before I end up with a compromised fuel tank. The treatise in the attached link explains a lot of the fuel vent system and makes sense to me. While it deals with the H&E fuel system, the vent system is common across the XJS range from that era. H&E fuel system complications are the additional fuel tank and pump.

Jaguar Fuel Problems

Confirmed that the vacuum line to the Rochester valve is drawing a good vacuum with the engine running (Rochester valve is the far left valve in the photo below of my LH front wheel well facing forward, vacuum line is the smaller line connected the top). When I disconnected my fuel vent line from the Rochester valve, immediately the line starting hissing and I could both smell and see fuel vapor coming from it.



I left the line free and zip tied it to a fixture so it wasn't dangling as a temporary fix. Whole thing took less than 5 minutes. Not sure about the wisdom of venting the fuel line to atmosphere long term though, so will have to troubleshoot the Rochester valve and think of a more permanent fix.

Cheers,

Will

 

So basically my venting will be directly out of the boot?
I guess my next question is if that's the possible location of the problem, wouldn't I be able to locate the fumes in that area simply by smelling the connections?
I'm removing the boot interior this afternoon and leaving it open then actually attempt to use my very sensitive nose and try to pin point a general area. The few times I've tried to find the strongest area, I hadnt removed all of the carpet and pieces but it really seems to be coming from the lower area of the tank. The vent area, even on the worst days, doesn't seem to be the source but if you are telling me it's output is not in the same location, that could change my thinking!!!

 

If the tank is pressurizing, it will force gas out at the weakest connection. Fuel filter seems pretty common, which is in the boot... hence the gas smell there.

Cheers,

- Will