Can someone please tell me how to remove and check the fuel temp switch? Do I need to depressurize the rail first? How do I tell if it's stuck in the closed position? Problem remains running rich.

Thanks

Rodd Leeds
1988 Cabriolet 5.3

Submitted by dougdwyer@adel… on Sat, 05/13/2006 - 00:15

Heh heh. A f/p test isn't easy on a V12 as Jaguar made no provisions for one; ie, a Schrader valve.

If you have a good assortment of fittings you can disconnect either of the two fuel lines going to the rail from the regulators. Otherwise you have you'll cut one of the rubber lines (again, between the regulator and the rail...I use the left side hose as it is more accesible) and splice in with a "T" to your pressure gauge. This means replacing the rubber hose when you are done---no big deal as the hose just pushes on to barbed fittings. Getting the old hose off the barbs takes some careful slicing---don't knick up the barbs. Make *sure* to use F.I. grade hose

Doug Dwyer
Longview Washington USA
1987 XJ6 Ser III
1988 XJS V12 Coupe

Submitted by rleeds9@yahoo.com on Fri, 05/12/2006 - 23:52

Thanks Doug! I'll check it out this weekend! also, if I need to do a fuel pressure check, where do you recommend inserting the pressure gauge? And I assume that in this case I would need to depressurize the system..

Rodd

Submitted by dougdwyer@adel… on Fri, 05/12/2006 - 20:47

The fuel temp switch closes at at a predetermined temp (170??F sticks out in my mind for some reason--could be wrong). This cuts off vacuum to the pressure regulator and allows full fuel pressure.

Under normal conditions it should be open. Just pull the hose off the regulator and put your finger over the end...you should feel vacuum.

Testing when hot may mean artificially heating the switch and retesting. You'll probably have to remove the switch to do this. On my '88 its a little tricky as one of the fuel line hold-down bolts interferes with one of the hose nipples on the switch.

The switch never actually contacts raw fuel so you can simply remove it--no need to depressurize

Cheers

Doug Dwyer
Longview Washington USA
1987 XJ6 Ser III
1988 XJS V12 Coupe