Jaguar Repair/1984 xj6
After draining the fuel tanks i put 5 gal. of gas back; but i'm only getting air pressure from the fuel pump. What do I have to do to get the fuel to flow?
If the pump is trying to pump air with 5 gal in the tank then you either have the wrong tank selected or you have a failed tank switching valve in the bottom of the spare tire well.
When the left tank is selected (default tank) you should have no power on the valve. The valve is spring loaded to the left tank and when power is applied it should "Click" and close off the left tank and open the right tank.
The preliminary test is to disconnect the power wire from the valve and leave the ground connected. Then apply a powered jumper wire to the loose power wire on the valve. You should hear and even feel a "Click". You should also hear a "Click" when you remove the power. This is the spring returning the valve to the "Left tank open" position.
If you have this and still not getting any fuel from the left tank you need to pinch off BOTH large hoses from both thanks and remove the valve and bench test it for open and close operation and check the flow of fuel from both tanks.
When you get it working, let me know and I will go over the tests for the return valves and the switching process.