I've been studying the XK8 wiring and Can't find the fuel pump relay listed an any of the diagrams except older ones where it is NO#4 in trunk (Boot) fuse box. That position is empty in my 2005 XK8. Fortunately mine is working where ever it is hiding.
Any idea?

Jack

 

Jack,
There isn't a relay as such in the 4.2L cars. It's now a Fuel Pump Module, located here:

 

Thanks Michaelh, I would have never found it.

Jack