Dear All,

I own a couple of classic Mercedes and have decided to add a XJ-S to this collection. I bought a 1989 V12. I am pretty good with anything electrical and mechanical (have overhauled couple dozen engines in my life).
Anyway, I am new to British cars and need all your help. My car was not driven for a while and the PO and a squirrel have rearranged a couple of things in the engine compartment. The stuff the PO has done is more disturbing as the squirrel only chewed on cables and rubber accessories (easy to sort out).
I have uploaded pictures in regards to my questions to a server and will post links below to these pics.

Q1: I have two caps on the coolant reservoir, one actually screwed on the other hanging. Other than the PO being lazy to cut the old one down, do you all see a reason for this?
http://zaruserv.uta.edu/XJS/two-caps.jpg

Q2: The space right in front of the distributor, there is a connector not connected to anything. Is this normal? If not what should it be connected to or what is missing (there is a similar connector right next to it that is connected)
http://zaruserv.uta.edu/XJS/mistery-plug.jpg

Q3. At one point the PO decided to unscrew a valve from the firewall. What is this valve for?
http://zaruserv.uta.edu/XJS/loose-valve.jpg

Q4. This is probably the most important. Close to the ABS/brake booster electronics, there is another valve. (I guess it is the one denoted as "solenoid air switch" in the Haynes book). I guess this should not be loose. Where does it need to go (i.e., attached). And what does it do? (Could anyone take a pic of theirs and post?)
http://zaruserv.uta.edu/XJS/another-loose-valve.jpg

Q5. The PO ripped out the cruise control actuator. I can see the actuator cable being wound on the cross brace. Where was the actuator mounted? Is the black electrical plug in the picture (on the brake fluid container) the plug for the cruise control? (again, could anyone take a picture of how it should look like?) Would an actuator from an XJ6 be the same?
http://zaruserv.uta.edu/XJS/cruise_control.jpg

And finally Q6. Under the left air intake (once the filter is removed), there is a metal (air?) piupe going down and there is a rubber elbow. I guess these two should be connected and secured to each other. But what is this and what is the function of the pipe?
http://zaruserv.uta.edu/XJS/hose%20and%20pipe.jpg


Thanks for hanging on, and I appreciate your time to answer any or all of the questions.

Greg

 

1) Lazy previous owner

2) Don't know

3) Looks like the heater valve from here

4) Looks like the extra air valve which fits into a grommet on the back side of the RH air filter housing. If your RH air cleaner housing doesn;t have an empty hole, I'm wrong :-)

5) I don't see a cable wrapped around the cross brace, only some wires. The actuator mounts ahead of the distributor. I'll try to find a pic for you. I don't know what those cylindrical connectors are but they only exist on Maralli igntion cars such as yours. I always wondered what they were for

6) If I'm lookin' at the right thing I think that is the aluminum drain tube that runs from the air intake plenum below the wiper blades.

Hope this helps

DD

 

@Greg

Welcome to the forums and to the joys of XJS ownership!

In case you haven't already, go to the net and google "Kirby Plam XJS book" and then download it and read it. Lots of useful info in there.

When you read the book you should pay particular attention to 2 items which can potentially rid you of your prized XJS very quickly. 1) Read about the fuel injection hoses between the fuel rail and the injectors. These become brittle and perish very quickly due to the heat in the engine bay and are a potential source of fire if one of them bursts. I would suggest you replace these ASAP, unless you are 100% sure they have been done very recently, ie within the last 1 or 2 years. 2) The Marelli ignition system, which was introduced to replace the Lucas system which was prone to having the advance mechanism stick, has a very unique failure mode which can lead to LOTS of unburned fuel going into one of the catalytic convertors with a good chance of a fire as a result. Read up on this so at least you are aware of it. There are various preventive steps you can take to reduce the risk of this failure occurring, but I think it pays to fully understand it anyway. I had read up on it when I bought my XJS, but despite having the knowledge, when I did actually get the failure (one coil failed resulting in no spark to the entire LH bank) it was not obvious what had happened, and I drove the car home (only 1 mile) but by the time I got back to my garage my catalytic convertor (and chassis rail and steering rack boot) were well alight. I had a fire extinguisher in the car so managed to get it out (I now carry 2!). You have been warned !

I would also recommend buying a good workshop manual (I've never seen the Haynes manual for the XJS so I don't know if it's any good, and for me with a facelift car there's only going to be limited overlap anyway).

I got mine the proper way, paid cold hard cash for it, but it paid for itself the first time I used it so....

http://www.bentleypublishers.com/jag...5-88-Work.html. This one has all the wiring diagrams in it. If you're still struggling with your mystery plug I can have a look once I get back the US (mid next week)

I'm not going to be much help as 1) I'm currently in Taiwan (car is in the US) and 2) I have a facelift '92 V12, which has quite a lot of differences, but anyway, here goes.....

1) As you know there are 2 caps for the V12. One on the front of the block and the other on the expansion tank (in your picture) On prefacelift cars the pressure rating on each cap was different (16psi and 20psi I think, but I can't remember which way round they go) Because of this Jaguar cunningly fitted the one on the expansion tank with a chain..... that way an owner couldn't mix the 2 caps up and put them back on the wrong way. I'm guessing that the original cap on the expansion tank (the one with the chain on) started to leak as either the rubber seal degraded or the spring weakened. Your PO fitted a new cap and didn't bother to remove the old one.

2) From the look of your distributor your car has marelli ignition, which has 2 coils, one per bank..... on my car one of the coils is in the "hole" where your picture is centred...... does your car have 2 coils ? If so where are they ? (For a number of reasons people modified the ignition systems on V12 XJSes) One of the modifications I'd seen was changing a Marelli system from double coil to single coil. If you only have 1 coil then the plug may have been leftover from the original 2 coil arrangement.

3) My car looks different in this area, sorry

4) Agree with Doug

5) The cruise control actuator connects to the throttle housing by a rod. It sits in the middle of the V, towards the front, kind of where the "hole" is in your Q2 picture. It looks like a round rubber barrel thingy, hopefully you can see it in this picture...



The actuator is driven by a vacuum pump on the left hand inner wing. I have all the components for the cruise control but mine doesn't work, and I've done a lot of troubleshooting and only managed to completely confuse myself, so I'd be cautious of assuming you just need to get all the bits together again and it'll work. I am 70% sure my ECU isn't working, and a new one is horrendously expensive, so for the time being I'll just use my foot to control the cars speed :-)

6) Some part of the amazing emissions system on the V12 which may or may not actually mean the difference between passing SMOG and not passing SMOG. Connect it back up anyway

This forum and board is excellent for the newer cars (I have a '00 XJR also) but for the older stuff there are less of these cars around now so the knowledge is getting thinner. Doug is very good, as is Ken from britishmotorsports, and there are a few of us "newbies" (myself, Blackjack, SERE, rama) all struggling along in the dark together so hopefully we can be of some assistance.

Another board that may be helpful is jaglovers.org, but personally I find their forums and search engine kind of frustrating and difficult to use, but there is some good info in there if you have the patience to look

 

Thanks everyone. You were right on.
A1. I removed the old cap that was missing a rubber gasket and drilled a hole in the other one to hold the chain.
A2. As the cruise actuator is missing the connector probably belongs to it.
A3. I fastened the valve to the firewall, which was not easy - very small space (probably the reason the PO did not do it). I decided just to get a 2" long 1/4-28 bolt and weld a nut onto it. Thus the bolt protrudes now and can be easily removed or put back.
A4. The reason for the valve being out is probably that it sticks. I have to get something else. Yet, how dumb is it to leave a 1/2" hole in the airfilter housing open, especially that it is on the filtered side...
A5. Remains to be seen. I am addicted to using the cruise control, so I'll end up fixing this anyway.
A6. The water release pipe from the heating intake grill area has been fastened back to its rubber hoses.

I will probably have more questions later. Thanks!