Hey Lads,

Wanted to capture this from the beginning for the benefit of others.

My XK8 has been running pretty flawlessly for some time now until last night on my way to the movies.
Car was running fine and I was circling up an on-ramp when I noticed a weird smell. Thought it was coming from the area but it was persistent.
As I merged into traffic, suddenly the check engine light started to flash and I noticed the engine beginning to stumble. Could still smell something that could be described as electrical but not 100% certain.
Car then flashed up "Restricted Performance" and since I could smell something, decided to get off the freeway again and have a look. Once stopped, distinct misfire happening from bank 2 (my central resonator has been removed so pipes for each bank)
Shut car off and waited for several minutes and restarted - problem is permanent.
I will grab the codes from the car today. I did have my OBDII scanner on-board and got several codes at once from misfire to catalyst, etc but I want to hook up the Jaguar software to determine the real codes and potential causes.

As I sit here, I believe it is simply an ignition coil failure and wanted to post about the "smell" aspect because that smell happened almost simultaneously with the performance reduction. Not sure if the two are connected or if a failed coil would even emit a smell but thought it relevant for others in their quest to resolve issues. Stand by and I will get the codes listed (there were 3 in total)

 

Thanks Bernie, look forward to your findings.

John

 

So as it turns out, this was about the easiest diagnosis I have ever had with the engine on this car.
Yup, single ignition coil failure on cylinder 2.
BTW - firing order on this engine is front to back, left to right with cylinders 1 and 2 being front of engine.

What the computer does when a ignition coil fails can be alarming as it is not subtle. There were a total of 3 codes thrown in OBDII but I only found the one code in the JLR software.
As far as I can figure, the computer can easily pinpoint the affected cylinder but is not quite confident on whether it is a failed ignition coil or fuel injector or something electrical upstream so it assumes the worst.
The worst being a flashing engine light and corresponding "RESTRICTED PERFORMANCE" illumination on the driver display. It does all of this because it assumes that raw fuel is being dumped into the exhaust which will make short-work of your catalytic converter if not treated quickly. I only put about 5 miles on my car to nurse it home after I received the alarms, warnings.

I went out yesterday to see if I could use the JLR software to track down a result but it was not helping as there aren't any ignition coil monitors on the software and I am perplexed as to why that is? The JLR software doesn't work very well on the 2003 cars but works incredibly well on the 2004 and newer cars. I know this because my buddy has a 2004 and using the software on his car is super easy and efficient. I finally just went old school and believing that it was indeed #2 that had the bad coil, unplugged it while the car was lumping in idle and there was no change. I then unplugged #4, the next cylinder and the idle dropped severely and the car stumbled. Plugged it back in and everything went back to the original lumpiness.

As a final test, I swapped the coils around in #2 and #4 and got the same result but on the newly lumpy cylinder #4 instead. So in this case - old school diagnosis won the race.
I felt it was going to be simple as when the problem cropped up, I wasn't in the throttle at all really and it wasn't dramatic. I am still curious about the smell though and at this juncture, I believe that when the coil failed, something might have burned up inside of it that caused the smell but who knows?

Codes pulled from my trusty Harbor Freight CEN-TECH, OBDII scanner were -
- P0302 (Generic OBDII) - Cylinder 2 Misfire Detected
- P1314 (Jag Specific) - Misfire Rate Catalyst Damage Fault Bank 2 (this one seemed like money burning)
- P1316 (Jag Specific) - Injector Circuit / IDM Codes Detected
These codes were coupled with a steady MIL status engine icon at first and then subsequently went to flashing icon with the RP warning on the display.
Yeah, its enough intel all at once to make you shudder a bit. I know with the burning smell, I wondered why I don't have a fire extinguisher in the car (fixed that already).

So I do not know anything else about this outside the scope of my own problem but I assume that the codes and conditions would be very similar if any ignition coil fails on cars at least 2003 onward.
Found a NGK replacement coil on Amazon for 40.00 and I am waiting on that now. I guarantee you that this is a very simple DIY to do and takes no more than 20 minutes to swap a bad coil out.
NGK U5082 48267 COP Pencil Type Ignition Coil

Hope someone else finds this helpful.

 

Wow, great write up, thanks! Before reading this, I'd have thought a single ignition coil failure would have been less perceptible.

John

 

A similar thing happened to be about 5-6 months ago. Car all of a sudden was misfiring like crazy. Had P0307 and P1316. Swapped coils, but misfire didn't move. But, I unplugged coil 7, and still no change in feel (obviously got a new code). So, it was definitely a spark issue. Pulled the plug and it was covered in weird residue from a fuel system cleaner from an otherwise reputable company (not techron). Swapped in a new plug, and haven't had the issue since.