Love my 1986 XJ6 - BUT - on the drive home after purchasing, the fuel gauge quit working. The fuel tank switch doesn't work either - no fuel gauge readings and the actual changeover valve doesn't perform its function. Should I be digging into switch testing and diagnostics or is this a common issue usually solved by ????? Any help would be appreciated.

 

Not that uncommon but can be fixed fairly easily. There are several extensive threads on the topic here. I would start with a 12v test light and see if you are getting any power at the changeover valve. If you can't find the threads let us know and we can help.

 

Take a look here:
https://www.jaguarforums.com/forum/x...g-unit-166388/
(';')

 

And here
Fuel Tank Switchover Checklist, Series III XJ6

 

OK - finding all the thread info I can and getting up my courage. Shouldn't be too difficult. First I have to get the MG ready to go north to Oregon for the summer and park the XJ. In the meantime, I'll study up and gte ready to work with the demons. Thank you for your help.

 

My XJ6 had sat unused for the last several years and the switchover function didn't work correctly. Exercising the switch on the dash didn't seem to do anything and the fuel always read the same for both tanks.

If I filled one tank and not the other, they would eventually equalize to half a tank in each.

It seemed to me that the most likely failure mode was a gummed up switchover valve in the boot from having sat unused for long periods of time.

Waited until the tanks were mostly empty and then removed the switchover valve in the boot. I took a plastic rod and exercised the plunger - it was sticky. I squirted some WD40 into the ports and exercised the plunger manually maybe 50X or so until it shuttled freely in the housing. Checked continuity in the coil too while I had it out.

I reinstalled the switchover valve and everything worked fine. Took about a half hour.

Had it not worked, the next step was to go through the electrical diagnostic that Doug D wrote and posted in Yellow Series3's message.

 

Sounds like a good place to start. I'm going to check the switch just to make sure the connections are all good into it, maybe use a quick spray of de-ox (Honda Goldwing taught me about effects of oxidation on switches).

Thanks for your help and suggestion.