Well, last week I took a drive with my new steering wheel on and the top down, and went over to visit family.....when I came back out, the car was idling extremely quickly and i noticed that when I applied the brakes and then let the brakes go, the car would move quickly ahead. That was traced down to a faulty AAV valve that all of a sudden gave up on me.....after replacing it, and one throttle bushing, I heard a very loud "hissing" sound coming from the driver side area of the engine in the area of the new AAV....after much frustration, I found the source, which is an open vacuum port under the intake manifold, right under where the "r" is on the Jaguar decal on the same manifold (6 litre XJS). The trouble is, I can't for the life of me find a hose that came off of it, nor do I know what it is for. I have included a picture that i took after much finagling with my iphone camera . Does anyone know what this vacuum port is supposed to be attached to? Also, in the second picture, I located what looks like another vacuum line with a small filter on the end, that is not attached to anything ? Is this related?
Any help would be appreciated, thanks guys!

 

Im not to sure how to attach a second picture in one thread.....so here is the second pic

 

The one with the filter should go to the distributor cap as a "vent" and the other end hooks to nothing (that way at least on the 5.3) the one you can't find a hose for may have just been "capped" off and the cap fell off which would explain why you can't find a "hose" to hook on to it. Just some ideas.

 

Difficult to see in that picture, but my 6.0L has 3 hose connections off the LH manifold. The front 2 are capped off and the rear connects to a metal pipe that runs under the intake manifold with another rubber hose that connects to the jackshaft cover under the throttle capstan.

 

I thought a picture was worth a 1000 words

 

Hmmmm......looks like it was capped off then.....and the other thing is a distributor vent, interesting!
Thanks a tonne guys!

 

Here's a little insight.

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XJS, Early, Distributor Cap Venting, Fuel Injection, D-Jetronic

I tend to block out the late 70s, D-Jetronic, XJSs. These are prime candidates for V-8 conversions. I just don't see any of them anymore. The underhood temperatures were so high that it makes everything rock hard and brittle. Having a car crumple under your fingertips while working on it just makes your day. One particular recall concerned the distributor. The crankcase had a tendency to vent into the distributor body and up into the cap. In extreme cases of neglect, in my opinion, enough gas contamination in the oil would ignite from the secondary spark. The only possible way the oil could be that contaminated is by exteme rich running conditions for a long period of time or for very long intervals between oil changes. This is the reason the late XJSs have a vacuum venting system and shield on the distributor cap. The crankcase still vents up into the distibutor and tends to bind up the centrifical advance. Luckily I started working on Jaguars after the glory years of being funded by the queen's reign. I've seen only constant improvements. I'm not familiar with the fuel rail recall except that there is evidence of changeovers to the later style rail on some 82-84 XJSs. It's great that this group was formed, some of the info found here is invaluable. I'd like to see a group for Jag techs someday. The best source of info on the cars is a conversation between four or five mastertechs at lunch at the training school in Irvine, CA. There is just no substitute for dealing with the same product day after day. So everybody continue on with their love-hate relationships. Jaguar established quite a name for itself in years past, specifically with the XKE. The mystique has carried on to the present. The cars are still quite exotic to the average person. This is all good news to me of course, it reflects directly on my wallet! Life is good. <<<<<<