Good evening, gentlemen. I am now three days into ownership of my 1987 XJS V12 5.3L car. I am slowly looking around to familiarize myself (brand-new to Jaguars), and look for visually obvious problems. The car runs pretty well, aside from surging at idle (in neutral, drive= no surge), which I am guessing is a vaccum leak. I will be replacing all vaccuum lines.
During my inspection, I noted that the Supplementary Air Valve (SAV) was loosely fitted to the RH airbox without a grommet. Furthermore, the two wires coming from the unit are not connected to anything, it appears that they could link to each other?? I have to confess that (so far) I have not the slightest clue what this unit does... Picture attached
Item #2 is the discovery of what appears to be an in-line fuel filter strapped under the RH fender brace, the fuel line runs back towards the firewall and behind/around the motor? There is nothing attached to the other side of fuel filter (which would be towards the front), and no sign of the missing rest of the line. This part, also, I have no idea where this fuel line comes from or goes to.... I believe it is fuel line, the filter seems readily identifiable... Picture attached


Supplementary Air Valve- two wires just hanging loose

RH fender brace- fuel filter bare end faces forward.

So... What to do? I will get new grommet for airbox, but what to do with the two wires? Will re-connect fuel filter line once I know where it is going...
Thanks in advance for any clues!!
John

 

Fuel filters used in that fashion are usually there to provide clean, ambient pressure for a module that wants that. It's a little air filter. Just basing this off of similar applications on aircraft i've worked on. Don't have a XJS yet.

 

Copy that! Now that you mention it, it seems there was something similar in the setup for the gyros in my 1958 C-172....

 

The small filter is for the distributor vent system

https://parts.jaguarlandroverclassic.../brand/jaguar/

Cheers
DD

 

Dig around a bit more in the vicinity of the SAV. You should find the connecting wires dangling loose. Most likely Brown/slate and pink/white or brown/slate and yellow/black

Cheers
DD

 

And the SAV inlet to the air filter must be sealed with a grommet.

 

Thanks, guys... I will root around under the hood and see if I can find the feed wires to the SAV. Distributor vent filter eases my mind!

 

FYI the solenoid valve is wired (when connected) to come on with the aircon compressor to guard against stalling when the car is ticking over, as in traffic for instance.