Where does this vacuum hose go?

I’m not finding any Purge Control valve anywhere. Only vaccum tubes to to the cansister area, no wires (except for lights) and they all end on manifold vaccum connections. 3 small ones and one big one. So maybe it was removed before I got the car and that was originally part of the Purge valve wiring and was left unconnected.

Yeah, carbon canister system is all vacuum, no electrical – post-recall, anyway.

What about the air pump? It runs all the time, but there’s a valve that switches its output from exhaust tract to RH air filter housing. Is that valve vacuum or electrical? I don’t remember.

Pages 17-2 to 17-9 of the XJ-S ROM covers this Purge Control Valve in the Emissions Control section on “Canister purging” for the 1979-1984 MY cars. It is shown as component “W” in figure 11 on page 17-2. Neither of my 1990 V12 Jaguars has this Purge Control Valve but my Series III XJ6s do inside the engine bay nearby the carbon canister. There is a 45 second timer associated with it to prevent purging the carbon canister through vacuum until after the catalytic converters are “alight”.

Paul

The air pump diverter valve is vacuum controlled by a thermo valve at the rear of the right coolant rail. The purge signal goes through a similar-appearing thermo valve near the front of the left coolant rail. Perhaps the vacuum line is off of this thermo valve (located near the FFI temp sensor).