We are making an assumption here that the problem is the cap/rotor. It’s not the only possibility but is the most likely. I would suggest you do what Kirby mentioned above before buying any parts:
Just remove the distributor cap and rotor, turn the rotor over and look at the bottom of it.
There are pictures that show the various possible failures of the cap/rotor. It could be just the rotor. http://www.jag-lovers.org/xj-s/book/Marelli_pix.html
Inspect the cap and rotor for the failure modes shown in the pictures.
If you need a repair manual the Bentley Manual is a good choice. Although it no longer says “Bentley” not sure what happened there. There may be other options…I’ve been away for awhile.
Okay thanks I just purchased the manual you linked me to Matt, Will be about a week or more before I receive it. I tried starting the car today with my toyota connected to it and it wouldn’t start :(. To take the distributor cap off do I have to remove anything before that to gain access? Or is it just a tight fit? Just got off from work so will see if theres any tutorials or how to do it
Steven,
To remove the Marelli distributor cap you need to first disconnect the cruise control actuator (3 bolts, 2 connectors, 1 vacuum hose) and relocate it to the side. Then you need to remove the top coil being careful not to damage the connector or wires. Then remove all the spark plug wires from the top of the distributor cap, and unscrew the three captive screws holding the distributor cap on. There is a gasket between the distributor cap and the distributor that might make it a little difficult to remove the cap. But once the three screws are loosened up all the way you should be able to remove the distributor cap by pulling up on it.
Thanks Paul the cruise control actuator that’s the bellows that I read other people refer them too? Mine is broken it looks like. I will remove that tomorrow sounds like a plan!
Steven,
Yes. That rubber bellows is part of the cruise control actuator assembly. It also includes two solenoid valves on one end plate, a spring inside the rubber bellows, and the other end plate that the cable to the accelerator is connected to.
Steven,
One of the challenges we deal with on the V12 is the extreme heat that occurs in the “valley” between the two cylinder heads. The A/C compressor blocks any air flow through the valley and the result is high temperatures which over time cause the wiring and plastic connectors that live in the valley to get quite brittle and as you noted, crack easily. The fuel injector wiring is also subject to the same problem. Be careful as you remove any wiring and connectors to minimize the damage.
I also removed my cruise control unit as the bellows had gotten all distorted and the innards were falling out. I have it on the work bench for the time being until I can get a replacement bellows.
While you have the opportunity, go ahead remove that spark plug again and check the gap. I checked one of mine and sure enough it was at the out-of-the-box 0.035” instead of the proper 0.025” gap . So, I will be removing all the plugs one of these days and re-gapping them to the correct setting. Come to think of it, I’ll probably just replace them since I don’t know how old they are.
Matt
Steven,
The engine will idle smooth on the B bank it is just a six cylinder engine then. I had the same issue, cooked the cats on the right side, but knew what was going on. You will need to clean out the right side exhaust with the melted cat substrate. This is caused because the spark plug wire break down over time and as the resistance increases the spark will jump to the block through the dizzy shaft, here is a photo of a stock and “modified” dizzy. You should do this while you have the cap off, also Magnecor 8.0mm wires will not break down like the carbon stock leads and I believe negate the need to trim the dizzy shaft. Since your there you should trim the nob down, but be sure to put the rotor back on right because with the nob gone you can replace it 180 degrees off.
Dan
Okay so last time I ran it, the car died on me while pulling into my driveway, I was able to jump the car and get it running again, I probably let it idle for a good 5 minutes and then parked it in the garage. later that night I wiped down the engine bay being very careful with a wet rag. Next day I had someone come take a look at the car to help me work on the fuel smell issue, tried starting the car and it wouldn’t start. So far I have tried jumping and also hooking the battery from my other car directly and it still wouldn’t start. Took off the cruise control to check HT spark plug wires and one wire on 2B is damaged. Tried taking spark plug out but they are seized on there, waiting on getting some WD40 to soak them and hopefully get them out. Checked the set of 3 wires going into each ignition coil and they get power/signal. I can hear the fuel pump working. Pulled the boot connector going from the ignition coil to the distributor and stuck a screwdriver in there to see if I could get spark, didn’t see anything. Is there any fuses that I can check that would cause a no start? I would like to get the car started before I start renewing the engine with new parts. Thank you. I added some photos to help follow along
The fuse you have circled is for the AC compressor clutch.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
33
Well, no, silver is actually an excellent conductor. Speaking of colors, though, the silver-colored terminals in an aftermarket distributor cap are made of aluminum, which is a good but not great conductor.
That’s not really the problem, though; aluminum conducts electricity perfectly well enough for the distributor cap application. The problem is that the presence of the aluminum indicates it’s an aftermarket cap, and the aftermarket caps don’t have the quality of the original Marelli caps. Among other things, the plastic is thinner, and the thinner plastic invites high voltage to burn right through it.
Steven,
When you say the car won’t start do you mean it turns over fine but does not fire at all?
Best thing to do is pull the spark plug wires off the distributor cap and remove the distributor cap so you can examine it and the rotor. You are just avoiding the inevitable here. A quick visual inspection will be very helpful. In all likelihood you will be purchasing new plugs, wires, distributor cap, and rotor. This will get you back to a known state. Essentially, an old-school basic tune-up. The no-start problem will in all probability be resolved by this course of action.
Your wiring is in bad shape. Some electrical tape would be a good thing.
The screwdriver in the coil wire trick can be hard to do correctly. What were you trying to ground the screwdriver to and how much gap did you leave? If you search on YouTube for “Ignition Coil Test” you will find other (better) methods of checking the coil.
When I try to start the car, the mechanical fan (big fan on RH side) spins. Other than that the car does not start and run. My knowledge is limited in automotive so I’m unsure if my description means that the engine turns over, I’m assuming yes please correct me if Im wrong.
I’m hesitant to pull the distributor cap, because I have never done it before and don’t want to mess anything up. Is there anything I should look out for? I remember reading about how I could mess up the timing. I will eventually be renewing everything I can, just still trying to figure out this car and the best and most economical way to feeling the V12 smoothness. What supplier do you use? I don’t mind aftermarket non-oem stuff but I would prefer plug and play type parts/ minimal or at least easy modifications. Anyone know a list of interchangeable parts?
Removing the distributor cap will not affect the timing. Just remove the plug wires from the cap (make sure they are all labeled) then remove the three screws that hold the cap to the distributor. Pull the cap off.
That’s it. Then a couple of screws that hold the rotor on. Pull it off.
Regarding your other questions:
If the starter engages and “turns over” the engine then the pistons will be rotating in the cylinders, building up a compressed fuel/air mixture, which is then ignited by the sparkplugs (fire). Sometimes the engine will turn over and only some of the cylinders will be firing…it tries to start but cannot. In your case, it sounds like the left bank of cylinders was originally firing (enough for the engine to run), but not the right bank of cylinders. That’s why you need to inspect the cap/rotor.
Many have used rockauto.com for aftermarket parts. There are other vendors that continue to support the Jaguar market like SNG Barratt, Welsh, Jagbits, etc. which are listed in the back of Kirby’s book.
The spark plugs can be difficult to remove if the previous mechanic did not use anti-sieze compound on the spark plug threads when installing the plugs. This is due to the steel plug threads interacting chemically with the aluminum heads. This is a place where gentle persistence will pay off. Last thing you want to do is strip out the threads in the head. A breaker bar can be useful, rock the bar back and forth (loosen-tighten-loosen-tighten) with increasing pressure on the loosen side until it releases. Buy some anti-sieze lubricant at the auto parts store and use it on the spark plug threads when reinstalling the plugs. And don’t over-tighten bolts going into aluminum threads. A torque wrench is a good investment. The torque specification should be in the manual you bought.
Okay I disassembled some more parts on the jag here are the pictures, I’m not sure what I am exactly looking for but in my un-experienced opinion the Distributor cap looks good and the rotor looks good, didn’t remove the rotor from the car. Am I suppose to be able to rotate the rotor? and then it springs back while still in the car? If so I am unable to rotate the rotor at all.
Engine is extremely dirty built up old oil EVERYWHERE (weird because I don’t see any visible leaks), i’m trying my best to clean it, broke the passenger side hose that connects to the distributor. What part is that? looks like the other end of it routes to a part that sits under the fuse box on the drivers side (left) Didn’t get a good look at the part but it didn’t connect to anything it felt like.
What should I replace while I have the car in this state? Thank you, I have about 8 months to get this car driving again.
