Think I have a coil pack going down my fox scan says a code but not which one do anyone know how tell which one ?
Assuming an X300 6 cylinder.
Remove the coil cover and run the engine in a dark area. Sometimes a faulty coil will reveal itself by displaying a flashing or arcing inside the epoxy material. Unfortunately, lack of flashing doesnāt prove that a coil is good.
What some do is buy one new coil and swap coils around until the dud is discovered.
I suggest avoiding aftermarket replacements and find a genuine, OEM, made-in-Japan coil from Diamond Manufacturing. Such a coil will have labeling like an original but without the āLucasā sticker.
What code are you getting and what are your symptoms?
Cheers
DD
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X[quote=āDoug_Dwyer4, post:2, topic:355780ā]
What some do is buy one new coil and swap coils around until the dud is d
[/quote]
Idle without cover and unclip single coil connectors until you find the one that doesnāt cause the engine ro stumble even more thatās your dead coil
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Does the coil cover trap heat and cause premature coil failure ? Just a thought. I havenāt replaced mine after changing plugs a few years ago.
That method works perfectly if the coil has outright failedā¦which is the lucky and happy scenario with AJ16 coils and what we all hope for.
More commonly the coil failures are a bit ephemeral 
Cheers
DD
Hmmmm. I dunno.
Seems plausible.
It would be helpful if someone smart took a dozen or so faulty AJ16 coils, opened 'em up, and determined what the exact failure mode is. Like an autopsy.
The last 2-3 years of my X300 ownership was plagued with coil problems, largely (but not entirely) due to my very ill-fated decision to use some non-OEM replacements. You know itās bad when you carry a couple spare coils in the car. On the bright side, replacing them is very easily done on the side of the road.
Cheers
DD
Coilpack ignition, if it is via wasted spark, will connect two cylinders per coil. If two cylinders drop out then it is likely that coil, but if only one cylinder misfires, then it may be the plug lead to that cylinder.
kind regards
Marek
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Not coil pack Marek, Coil On Plug. No HT leads and dead easy to swap. I remember when I got my first Jag (one of this forumās X300s actually) I took a photo of the Jag (6 COP), my Triumph (3 COP), my year-old Corsa (3 COP) and my CCM motocrosser (I conventional coil).This was late 90s and the āAverage Joeā was not quite as familiar with COP, and three cylinder engines were rare.
I was going to do a puzzler and either
- Ask how many coils the machinery on view had (13), or
- Tell people there were 13 coils on view and ask people to guess how many on each machine. My bet was that instead of 3 & 3 someone would guess 4+2 etc.
Thing is have load spare 2 pin ones but I have too later Daimlerās with the 4 pin I think these have more problems I have now ordered a set 8 s/h ones will try change the 4 on o/s first
Iāve lost two in the last year. both at #1 cylinder (counting from front, unlike the XK engine). The replacement for the first fail was a used part so it probably already had high miles on it by the time I fitted it. 3000 miles later it too was kaput. In went another used one from the same vendor. Probably same donor car!
The misfiring coils are separately IDād by the OBD2 system I think. 0301-0306 in the scanner manual but it could be that the Jag early OBD2 only picks up misfire by bank? Either way, the first one was dud when I bought the car and the second showed a CEL after about 3,000 miles, manifested as an occasional stumble at first but it died within a week or two.
Interesting was your faulty ones 4 pin ? Ie 2000 too 2003 V8 my other 2 pin coils been fine even when the plug hole filled with oil from can cover gasket leak
Mine never set a misfire code throughout many coil failuresā¦or even if a coil was unplugged! Frustratingly, though, the OBDII just loved to set P0430 and 0420 codesā¦which I diligently tried to repair but eventually admitted defeat and just ignored 'em.
Mine was a 1995 car and there seems to be some consensus that Jaguarās version of OBDII was not quiteā¦ahemā¦ āfully developedā at that point.
That was a great carā¦XJR versionā¦ but there were periods when the much ballyhooed gloss of the X300s dulled quite a bit. Age and miles eventually take a toll on any car, I reckon. I referred to it as āThe Tormentorā due to various driveability and OBD issues over the years.
Cheers
DD
My last Jag was a mk 2 many years ago only one coil too worry about then how times have moved on
Courtesy of Jim Butterworth:
Scroll down for disected coils.
A few years ago I had what I thought was a failed coil pack on my 1995 x300. After identifying piston 2 as the culprit, I replaced the coil pack and there was no change. I did a compression test only to find a burnt valve was the culprit. I ended up pulling the head and replacing the valve. I sent out the injectors for cleaning to prevent it from happening again. I hope that is not your problem.
I just stumbled in here. Neither of my cars has a coil pack or coil on plug system. Iāve lived my entire automotive life with āone coilā cars.
But, I almost understand eliminating the distributor cap and rotor as a āweakā point. My LT1, as does Peteās Brontosaurus, relies on an āadvancedā cap and rotor system known as an Optilite.
I did mess with my daughterās VW V6 powered Passat. A very interesting Hemi head V6. Coil pack ignition. It developed a āstumble ort outright stallā Fault. Scared the wits out of her.
- My neighbor used a simple OBDII scanner on it. Intermittant misfires on 5 of itās 6 cylinders!!! Very helpful. Pointed to an ignition issue.
So, I mounted an almost all out attack. Limited as it had enjoyed a recent crankshaft position sensor swap by her gal palās pro tech friend.
New coil pack, wires and spark plugs. Sourced via Rock Auto. About $140.00. Not bad at all, considering.
The swap took a few sessions. Delays in the opening of the harness connector. A bear. Busted it. No matter, the new pack had one on it. Got it together. It fired right up and purred. Alas, daughter lost confidence in it. Bye bye Vw, hello Nissan !!!
- In a coil pack, as opposed to coil on plug, HT wires are there . Iāve never tried it, but it seems that an inductance timing light would detect nice even flashes as opposed to raggedy ones !
Today Iāll tackle the install of a driven pulley on my Troy Bilt Super Tomahawk chipper shredder. Lucky me. I now have two! One 6 HP, the other a full 8 ! The latter a bigger unit all aroundā¦ Related in name only to the new Troy Bilt gasrden products.
Carl
Isnāt technology great . Fifty years of owning and working on cars and never had a bad coil. Even though my X300 never had a bad coil, from everything I read I carry a spare in the trunk along with a Crank Sensor.
I had the stock K66 magnetic system in my old Corvette and only replaced wires, cap, rotor in 25 years.
Well the good news having got 8 s/h ones fitted 4 too right bank still same fitted 4 too left bank no more miss fire and able clear engine light . Now just got work out which one from left bank was duff
Which code(s) do you have?
Oops should had noted cleared them now came up with 4 codes one said coil circuit so I may be able test the 4 coils with a meter one looks new so with luck be one the other 3