Just had a new exhaust put on our 74 XKE, and looking at the install , on my lift, i see this fuel line , disconnected, at the point where the new system connects to the exhaust manifold … don’t know where it add Gould be connected .. any idea ? Thx Dean Robert

 

Are you sure that's a fuel line? It looks like it might be part of the EGR (Exhaust Gas Recirculation) system. If you have some of your emissions system removed my bet is a PO disconnected the ERG and instead of blanking off the manifold just bent the pipe under the car so it would dump the exhaust there. If so probably best to remove it and plug the manifold.

 

We followed the line aft and it looked like it was headed towards the gas tank ; i bet you are right tho ; my last mechanic , ( he has since retired) in an effort to get it running better, disabled a lot of the emissions stuff…
im in Springfield , Il - need a good v-12 jag mechanic … any input would be greatly appreciated

 

That is part of the containment system for fuel vapor. Careful plugging it as your car has a non vented cap (or should). If you plug the system you will pull a vac. and the car will stall from starvation. Good luck.

 

The 74 xke was originally designed for fuel injection which required a return line to the tank. They did not get it done in time and used four carbs. There is a line on the drivers side that has a back flow preventor which maintains the fuel pressure at no more than 3 lbs per square inch. Many people just plug the return line and the fuel pump runs like on a MGB. Not really a good idea since the Jaguar pump can overpower the needle and seat in the four carbs and cause catastrophic fuel leaks.

 

I agree with Coventry. If it's not connected to the exhaust manifold then it's likely it's the vapor return line that runs from the gas tank to a charcoal canister tucked just in front of the battery. Look to see if the canister is still there (it's round black plastic, about the size of a coffee can), if it's not then that's most certainly the answer. If it is the vapor line then remove the wood panel over the fuel tank and be sure the vent outlet is capped. You'll also need to make sure you have a vented gas cap as the tank needs some method to vent when it gets warm and the air inside the tank expands.