The gas gage on my 1985 jaguar xj6 is working and

It sounds like a change over valve is faulty. U have 2 check over valves 1 on each side of rear wheel wells. Also a change over valve that switches 1 tank to other. I recomend replacing all 3 valves for peace of mind,because when 1 goes the others follow. Hope this is helpful!

Dear cpr007 :

Your Question is in complete . I will try to answer it nonetheless . The gas gauge on your 1985 Jaguar XJ6 is working ?? If you are only getting gasoline from 1 of the 2 gas tanks then your problem possibilites are somewhat simple . Each gas tank holds roughly 12 gallons . One of the 2 fuel pumps is bad/defective or The fuel cross-over switch located on the middle dash panel is bad/defective or you may have a problem with the relay or wiring / ground going to that particular tank . Please note : Jaguars from this era were quite known for their electrical problems . This is a Series 3 Jaguar . Ground on this Car is the positive side (+) Not the (--) side like most American cars .

I hope this info helped you .

The one my buddy and I have has a single trunk mounted fuel pump loceated under the floor panel in the trunk. The switch over switch and fuel filters is there also. Easy to get to and work on