I'm building up my parts list for doing some fall/spring engine work. I've had my '89 XJS V12 for most of the summer and apart from a noisy transmission mount, she's been great. That said, over the years there has been some hacking at the harness in the Vee, and maybe it's time to bite the bullet on this one. So as well as a parts list I'm starting to plan a part rewire of the harness.

I've spent ages researching the quirks of the model. However, there's a sensor or the like mounted onto the front right side of the engine that's been completely electrically disconnected. The part is just forward of the Solenoid Air Switch/Supplemental Air Valve and connects via a small hose to the RHS intake manifold. On my car there's a small outlet at the top of the switch/sensor and a harness connector (disconnected) which leads to a double 3 pin connector (1 Black and 2 yellow with secondary marked wires) through a dedicated part of the loom. Unfortunately the markings on the sensor are now too faint to read and I'm having trouble identifying the part from either manuals or the wiring diagram. So any pointers would be greatly appreciated.

https://goo.gl/photos/anJTRrcYd28XWypV7

 

You talking about this?


I think it senses vacuum changes to divert pumped air. Thats what they do on carb'd engines since there is a fuel dump when you close the throttle. So its like like a blowoff/purge valve. (Anyone feel free to correct me if I'm wrong)

 

Genius. That's the part for sure. Many thanks.

In my case it's connected only to the intake manifold. The little 90deg spur is (I assume) missing a hose and the electrical harness is completely disconnected.

I'll have to dig deeper as my wiring reference doesn't contain these components at all; probably as it's a Canadian model. Thanks gain for setting me on the right path.