Jaguar Repair/FUEL TANKS
CAN I CONNECT THE TWO TANKS TOGETHER AND RUN THE FUEL OUT OF BOTH TANKS AT THE SAMETIME? THAT WOULD ELIMINATE THE PROBLEMS WITH THE RIGHT TANK OVERFLOWING (1987 jaguar series 111. OR IS THAT IMPOSSIBLE....
That would be very difficult to do because most of the fuel pumped forward is returned to the tank that it pumped from.
When you select the Left tank the large switching valve in the bottom of the trunk wheel well is turned off electrically and a spring opens the left tank and closes the right tank. This pumps fuel from the left tank up front and a pressure regulator sends most of the fuel back to a RETURN valve at the lower edge of the left wheel well under a small panel. That return valve is turned OFF electrically but open with a spring so the returning fuel returns only to the left tank.
The right tank return valve is also OFF electrically and spring loaded to the OFF position preventing any fuel returning to the right tank.
This is operated like that so if you have any electrical failure in the fuel valve system you can always operate off of the left tank.
When you select the right tank electric is applied to all valves which close the left fuel supply and close the left return valve and opens the right fuel supply and opens the right return valve.
If you have the right tank overflowing either someone put the wrong return valves in either side or you have a stuck open right return valve.
Use a 12v test light to confirm the power on and off as per the above. Also, put your hand on each valve to feel it "Click" when operated by the dash switch.
Let me know,