Hello

I have a 1986 UK spec Jaguar 4.2 series 3 sovereign which I have been working on for 10 years.
A fews years ago I removed the cylinder head for a re-skim and replaced all the gaskets.
Before removing the cylinder head the inlet manifold and associated cabling were removed.
The cables were labelled up but due to the time spent off the car and moisture some labels came apart.
I referred to my Haynes manuals (both standard and restoration) but I could not find any component matching
an electrically operated valve that sits between the auxilliary air valve and the air flow meter.
I have downloaded some very wiring schematics from American and Dutch websites which are far
more detailed compared to the schematics in the Haynes manuals.
The American manuals never had anything matching the component but the Dutch manual contains a detailed
component layout of the unit in terms of hose connections. Unfortunately it is still not covered in the
wiring schematics.
What I have learned is that the component is an extra air valve (EAC-6534) introduced to UK, European and
Middle East models between mid 1985 and 1986 when the series 3 XJ6 ceased production.
The component was not used in the North American models.
I have purchased the full jaguar series 3 service manual (AKM 9006) to see if this would provide answers
to how it is wired up.
Sadly it doesn't, even though the manual covers all UK series 3's (XJ6 and XJ12) from 1979 to 1992.
As well as the extra air valve there are 2 relays (black and red) which are located on the inner wing near
the air flow meter which look like they have some involvement.

So is there anyone on the forum who has a wiring schematic covering these components ? Or is there anyone
in (or near) the Midlands who has a 1985/86 XJ6 / Sovereign 4.2 I could visit and trace the wiring connections to create
a wiring schematic ?

I have attached a diagram of the components and how they are currently wired.

 

This won't be a whole lot of help to you..
But, I decided to crack open the Service and parts bulletins for you, to see what I could find... this parts bulletin tells exactly when the change was initiated, and what markets were effected.
I imagine the larger answer is somewhere in the service bulletins... It's about 557 pages and my mind gets sidetracked looking at all those parts, but I'll dig through a little more and see if there is anything there that may help...

For what it's worth, that air valve should work almost like a fuel changeover... Open to voltage and closed to no voltage would be my guess... You should have one that leads to ground (black stripped) and another solid...
Even if it were blanked off, it may not effect your starting much, depending on where you live...

Cheers
David Boger
Everyday XJ

 

David,
thanks for the repsonse. It would be great if you could find the how the unit is wired up. I just could not find it in the UK version of the service manual.

 

Just out of interest, have you tried the downloads from here?

Electrical diagrams.

Quite a few for XJ6 under different sections.

 

Richard,
yes I already have these manuals - A lot better than the UK manuals I've seen so far.

The interesting thing here is that the electrical schematics for the Series 3 XJ6 do not show or reference the part but it is shown in the XJS diagrams.

 

Legend has it that those [earlier] wiring guides (such as S57, S58, etc) were created due to demands from USA dealers who insisted on decent wiring diagrams. Since UK/Euro/ROW schemes never seem to have been included in the pages, the legend might just be true.

Later Jaguar published good diagrams for all versions

Probably because the supplementary air valve was used on USA-market XJSs

If you simply want your SAV to function (at least approximately) as intended I reckon it would be easy to devise a wiring scheme to accomplish that. If you want to return it to the exact original wiring scheme.....I'm no help.

Cheers
DD

 

Interesting that no relays are mentioned in the parts list....which thickens the mystery a bit.

Cheers
DD

 

Doug

Thanks for looking. I think my best bet is to find someone in the UK with a 1985/86 Series 3 and physically trace the wiring. Unless someone outside the UK has the same components and can trace them.

If I can find someone then I'll make sure it's properly documented and uploaded for everyone.

Regards

Steve

 

will repost