PLEASE HELP ! ! !
I just bought a 1984 XJ! It's a beauty, my first jag. But it have one problem. Every time I start it the right fuel tank fill and over flows out the fuel filler cap. The runs even when this is going on. I NEED TO HAVE FIXED-PLEASE ME_ HAS THIS HAPPENED TO ANYONE & and How did you Repair it ? ? ?
Thanks, Robert Griffith

Submitted by jagboy69@hotmail.com on Fri, 07/23/2004 - 05:13

If memory serves me correctly.. the switching valve is in the trunk near the pump.. and the return valves are behind each rear wheel hidden behind some plate that is usually rusty... If you find those are your problems, change the fuel hose too... for a couple of bucks it's cheap insurance.. I tried to buy one of these return valves for an XJ12 I had in germany and the dealer there wanted I think about 80bucks a valve!!! I got it online for a third of the price. You can check yours by removing the valve and applying 12vts to it... You'll know if it's good by blowing thru it. Hope this helps.
Jason
1969 Jaguar E-type(2+2)

Submitted by dougdwyer@eart… on Fri, 07/16/2004 - 19:38

Select the left tank. With the engine running open the right gas cap and peek inside with a flashlight.....there should NOT be any gas streaming in. Open the left cap and you SHOULD see fuel coming in. You have sorta look forward at an angle to see.

The link below explains checking the electrical portion of the system

Doug Dwyer
JDRC/NWA
1987 XJ6 III
1988 XJS V12 Coupe

Submitted by dougdwyer@eart… on Fri, 07/16/2004 - 02:46

Common problem...

The system is so designed that unsued fuel is returned to the *same* tank it was draw from. The is accomplished by "return" valves for each tank, located behind a tin plate in each of the rear wheel wells.

In your case I suspect that fuel is being drawn from the left tank but being returned to the right tank, causing it to over-flow. Sounds to me like your right side return valve is not closing. Most people replace both valves at the same time and wash their hands of the matter for another 20 years. Sometimes they can be removed and cleaned if they are sticky. Of course, if they fail electically there's no choice but to replace them.

If you are handy with a test light I can give you a checklist to verify the correct operation of the electrical portion of the system.

Good luck

Doug Dwyer
JDRC/NWA
1987 XJ6 III
1988 XJS V12 Coupe