Hello all, My first post here.
I recently bought a 1986 Jaguar XJS V-12 with around 100K miles on it. The speedometer does not work for one thing. I am pretty good with engines and have done several restorations, etc. Are there any good Diagnostic or trouble shooting manuals available for this car on this forum, or somewhere else? I bought a couple repair manuals from eBay and they are sadly lacking. The car does not run worth a crap right now. It is getting gas but appears to have very weak spark. I don't know how the injectors are and I have yet to figure out how to get the spark plugs out easily. Any help to point me in the right direction would be appreciated. And where can I easily find the engine number? Thank you.

 

well someone just pointed me the JTIS or Jaguar Technical Information System.. I just got it dowloaded (450 some odd Mb) and am installing it now.

https://www.jaguarforums.com/forum/s...ead.php?t=4172

 

Hey thanks. I downloaded ( 1 1/2 hours) and installed it. Unortunatly it seems to start at 1995 and mine is an 86. Probably will be of some help though

 

You should be able to still get the Jaguar workshop manual for this car. Try an internet search. You can still get the ones for the saloon on which your car is based.

 

Thanks, you're correct on that. Actually there are a ton of them on eBay. I bought a Hayes manual and another manual on CD. The Hayes is on poor quality paper and not very good. I also downloaded a book listed on this forum called "Experience in a book". It is very large and a great find. Lots of really helpful great stuff for us new guys especially. I now have all kinds of things to check for my ignition problem. And a lot of alternate replacement parts that cost a lot less, such as the ign. amp module which is actually sold by GM. Thanks again for your response.

 

Kirby Palm's "Experience in a Book" is a great resoruce, yes. It has info you'll never find in any of the factory publications.

JDHT (Google it) has various factory manuals on CD and represent great value for the money....especially since they usually include the parts catalogs, tech bulletins, and the upgraded wiring diagrams all on one CD. Be advised that they won't run on Vista, though.

Haynes is good your workbench wobbles because of one short leg.

Sorting out an old XJS can be a bit daunting but it's worth it in the end. Fabulous cars.


Cheers
DD

 

Also newly available, our file storage site. Tons of tech documents for XJS.

Files download.

 

Try this http://www.faxonautoliterature.com/home_one.cfm

 

Is there anything on the 77 xjs v12.

 

I'm on my way. Lots of really good stuff and helpful people here and I'm going to need it.
My 86 XJS ran when I got it but it missed a bit. It was delivered by truck. Then it missed worse and worse and now it won't even fire when i put ether into the intake so I'm tracking down the ignition. It has a very weak spark and I had the GM elec. ign. module checked at Advanced auto parts and they tell me it's good. so I want to try a new coil maybe. I suspect the alternator is not working also.

 

Depending on the type of work you are doing the tech info for 80s vintage XJSs will work for you. Brakes, suspension, differential, cooling system and some other fundamentals were largely unchanged for many years.

Fuel injection, ignition, and some of the electrical stuff changed quite a bit.

Cheers
DD

 

Not sure what your comfort and/or equipment level is but the coils can be tested. If you wanna just throw a coil on I suggest replacing the two-coil system with a single DAC6093 coil.

You might wanna pull the distributor cap for a look-see...and check the distributor rotor as well.

If you have time and money it's really practical, and in the long run, easier, to "do the vee". Remove the fuel rails and air injection, move the compressor out the the way, remove the throttle pedestal and then.......

-Have easy access to all spark plugs
-Repair crispy wires and vacuum hoses
-Check distributor advance mechanisms
-Replace fuel hoses
-Replace plug wires
-Clean the dirt and rodent nests
-Adjust throttle linkages
-Clean throttle bodies
-Repair cruise control servo
-Other things which I've forgotten at the moment :-)


I realize the car is new to you and perhaps you don't want to go this deep at the present moment but, from personal experience, the "do it all, do it once" approach is worthwhile. You won't have to think about any of it again for years and can move on to other projects.

Cheers
DD

 

I never used any document other than the official Jaguar workshop manual when working on my Series 3. It was very clearly written by experts who also gave lots of good advice. I suppose most of these guys are now either retired or dead now, but there are one or two still around like Roger Bywater(see below) . I also had the parts catalogue which had all the assemblies and parts in the form of exploded diagrams. Worth its weight in GOLD, and there may still be some around on the internet.

http://www.jagweb.com/aj6eng/

 

Thanks for the help. How did you know about the rodent nest? I had a BIG one right under the cruise control bellows. I don't know how this forum deals with "thread pirating" but I seem to have drifted away from "manuals". I think I should start ma new thread and call it "V12 engine diagnosis", or maybe "what the hell is this for"?
When I bough this car, I knew it had problems and the guy that took it apart and put it back together was more or less a "visegrip, no manual" type of mechanic. I inted to follow your approach and I now have the injectors and fuel rail off. There is a electronic fitting attached to the left side of the fuel rail with 2 wires and it is broke. Haven't found what it is for yet. Spark plugs are Autolite Platinum APP103. Are these acceptable? I'm thinking iridium? Plugs will be eay to replace now and I want them to last because changing them when it's all back together I think will be a nightmare. I only have one plug out so far and it seems to be mildly oil fouled. Could I use a hotter plug? I also intend to do a compression test and remove the valve covers and check valve clearances very carefully.
I checked the iginition at the coil wire and I have a good hot spark about 1/2" long. At the sparkplug it seems weak. And I applied voltage to the removed fuel injectors and they all work. Now I can't understand why it ran (but missed some) when I first got it. Then the next day it missed worse, and the next day worse yet. Then it wouldn't start or fire at all the next day. Kind of a gradual thing. There should be fuel and spark, so I don't know. I want to try to temperarily hook up the fuel rail and injectors and place little jars under each injector and turn the engine over and see if they all squirt out fuel. With the ignition disconected of course. Sound like a plan? After this entry, I guess I'll start a new thread. I do have a couple manuals, one on CD but I want to get the original factory repair manual. Is the compression ratio on this thing 11.5:1? Pretty high for todays gas. Later. Thank you for the help so far. I appreciate it.

 

They all do, it seems :-)






That would be best, yes.






Fuel temperature switch






Spark plugs are like oil and tires: a very subjective subject. I recall using whatever the manual called for in my V12....NGK, I think it was







How's the fuel look/smell? Possibly old/contaminated? If the car has sat unsued for some time (common with old Jags) you might have a problem there.





Yes, 11.5 for USA versions and 12.5 for most other markets. The design of the cylinder head allows high compression ratios on pump grade fuel.

Cheers
DD