Hi,
I'm trying to help my brother with his ex US 5.3 that he bought on an auction. I collected the car, a beauty with some issues. Brake lights not working is solved, needed new bonnet and bootlid struts and the low mileage has kept it in a very nice condition in and out. i myself have a later '96 X300 V12 which is not quite the same.
I found 2 hoses each with a red ribbon around it. One has a fuelfilter attached on the end, the other hose, also with a red ribbon, has a 90degr hose connecter attached to it. I cannot figure out where it is supposed to be connected to. It seems to come from the base of the distributor ( the one with the fuelfilter on the end), the origin of the hose with the hoseconnector is not quite clear.



On the back of the rh side inlet manifold there are 4 small outlets, one of which was open (not connected) and thus sucking in unmetered air. If I block it with my finger the idling speed drops somewhat. Therefor I capped it as you can see in the picture below highlighted by a yellow arrow.
What hose is supposed to be connected on that 4th port?

Thanks for your help
Olav

 

The red ended hoses are the distributor ventilation system. The one with the filter (it filters the air) tuck under the wing/body strut somewhere (I cable tie mine to something suitable). If you look you should see the end of this filter hose goes to the distributor body at the rear of the distributor.
The other end woth the 90° plastic fitting exits the top of the distributor and fits into a hose behind the B bank (ie LHS sitting in the car) of the engine air filter housing. VERY hard to see this hose without removing the filter box. but here it is in diagramatic form:
See components 4 and 5 in this diagram:
https://parts.jaguarlandroverclassic.../brand/jaguar/

Part number 4 is no longer available; but if you buy a suitable diameter 90° hose, you can fit one of these to it:
https://www.viperperformance.co.uk/s...eather-outlet/




You did the right thing to seal off the spigot on the manifold, but check around to see if there is a stray vac hose that needs to be there. It could be the modulator vac pipe from the gearbox should be there, or the heater unit vac source pipe, or the full throttle enrichment unit vac source. Pan back and take and post a wider angle photo in case something is obvious.

 

Hi Greg,
Excellent write up,very useful. It will be untill tuesday before I will have the opportunity to work on the car again. I will post any progress then.
I do remember a sharp whistle sound while idling but it was very hard to pinpoint its location. The car has air injecion and I was not sure if the whistle was vacuum or pressure.
Thank you so far.

 

Get rid of the air injection!

 

Greg in France, your photos look so familiar to me. A relatively simple XJS repair, yet you are bleeding. It’s been a cold winter in New Hampshire, so I haven’t had a good garage bloodletting in months.

 

Yes, that is but a scratch; however ther have been too many visits to the emergency rooms over the years. But I have discovered that White Spirit is an ace wound cleaner...

 

Today I made some progress but not as much as I would have liked. I did find the vacuum hose that was missimg on back of the rhs intake manifold. It goes into the cabin through the bulkhead. Also I pinpointed the hissing sound, earlier described as ‘whistle’. It is a vacuum leak at the inlet port for cylinder 1b, most likely the inlet manifold to cylinder head gasket.
Much to my frustration I was not able to find the attachment point where the hose out of the distributor base is supposed to go. I removed the cover of the filter housing, not the entire filter box. That will require some more digging and patience.

 

If I am correct it should look something like this:

 

Found it. Previous owner couldn’t be bothered to attach the distributor ventilation hose but instead plugged it
It was indeed very difficult to spot if you do not know where to look.