Small canister connected to Throttle Housing

Ref Jaguar Sovereign XJ 12 HE

Any idea what this small canister is and where it is supposed to go. I found it under the Airfilter Housing just like this.

Thanks

I believe that to be an anti-backfire valve, but no idea where if hooks up.

Lars, that is a one-way valve and if you can suck, not blow through the open end it will connect to the intake manifold. The hose looks very bad too.
David

Thanks David. Does that mean that the end of the hose as shown is not connected?
Lars

It looks like it is part of the emissions / vacuum advance control.
It would help if you could identify where the two hoses are connected to.
Aristides

heeman,
That canister is the Delay Valve (EAC4025), part of the emissions system. One end of the hose should be connected to the Thermal Valve (EAC4083) at the rear of the right side coolant pipe and the other end of the hose to the Switching Valve (EAC3827) on the Air Pump.

This is all detailed in illustrations in my copy of the “Jaguar Parts Catalogue XJ12 Series 3 and Daimler Double Six Series 3 RTC9886CE of May 1985”. I have found that having the Parts Catalogues for each of my five different Jaguar models has taken a lot of the mystery out of working on these cars. I highly recommend that you get a copy. I got mine on eBay for about $50 and having it has saved me a considerable amount of time sorting out parts questions and a lot of money when looking and comparison shopping for parts. I would not be able to keep my Jaguars running without my Parts Catalogues, Repair Operations Manuals (Service Manuals), S57 Electrical Guides, and of course the Owner’s Manuals (Drivers Handbooks).

Paul

2 Likes

Right. It looks as if it tore off and was longer originally, but Paul is of course right with his detailed description; Sorry.

1 Like

Thanks very much indeed. Very useful. I’ll sort it out.
Lars

Lars,
All of the ends of the hoses in your engine bay should be connected to something. None of them should have a loose end just hanging there. If you find that a hose is disconnected then that is a problem to be resolved. Some hoses are more critical than others, but all hose ends need to be connected to something.

Paul

1 Like

Words to live by…:wink:

Do golf tees count?

Paul Wigton,

Do submarines have screen doors?

:wink:

Paul

1 Like

Paul,
It seems that I have sorted some things out: On my Saloon Series 3 XJ12 HE one end of the vacuum hose that is connected to the Throttle Body goes to a Vacuum Valve (EAC4013), which I have located, and the other end goes via the Delay Valve (EAC4025) to some kind of Solenoid Valve (EAC3488). I cannot locate the latter. Can you give me some directions. Thanks.
Lars

Lars,
What country was this car originally sold in and what country is it in now? The emissions equipment varied from country to country. It would help to know what possible countries we are dealing with before I look into this further.

Paul

Hello Paul.
It is a Sovereign XJ12 HE sold in Denmark as new in 1985 and it is still in the country. Thanks.
Lars

Lars,
I just looked up that Vacuum Valve (EAC3488) in my Parts Catalogue and as I suspected that part was not installed in the USA XJ12 models but was installed on the “EUROPEAN ONLY” cars as shown on page 1J 04R of my Parts Catalogue.

If you don’t have a Parts Catalogue you can also see that Vacuum Valve along with the associated hoses and other components in the drawing on the Jaguarclassicparts.com website by searching for EAC3488

I can’t help with any pictures since my 1990 V12 Vanden Plas was not equipped with that part.

Paul

**
As Paul says, and the workshop manual confirms; the US and European ign advance layout differs considerably, Lars. Either will of course work, but mixing the two will not - and there might be some small ex-factory, model year dependent, variations on either. And then; a PO may have bastardized your set-up…
The basic part on the UK spec for timing control is the ‘3-way changeover valve’. Which switches dist vacuum between ‘ported’ and manifold vacuum based on engine temps as given by the ‘oil temp switch’. The latter also operates the supplementary air valve - which adds air from the air cleaner to the inlet manifold to improve hot engine economy…

A main difference, UK and US, is that the former uses oil temp to vary advance - while the US is exclusively vacuum controlled. In both cases, the complicated set-up is due to the high compression on the HE engines - requiring some precautions to prevent pinking?

The US set-up is related to emission control requirements, while the UK is sort of power output related…

So…?

Frank
xj6 85 Sov Europe (UK/NZ)
**