Hi I have a misfire on cylinder 8. I changed coil pack with brand Delphi technologies one and nsk spark plug and reset EML.

worked for 10 mins until I was on a steep hill then EML back on.

Ive heard x350 xjr is sensitive to aftermarket… is it possible that Delphi coil short circuited or something? And should I go for an NSK coil pack or OEM second hand.

either that or its fuel injector but a jag specialist I spoke to on phone said he’s only changed 2 in 30 years experience and he doesn’t think it’s this. Wondering if it’s worth getting new coils and testing this before getting it in garage.

my codes:

p0300
p0308
p1314
p1316
p0208

many thanks

car XJR 4.2 SC x350 2005

 

Moving the coil, then the spark plug, then the injector should give you an answer.

 

thanks for your reply… the injector is located under the supercharger so it’s quite expensive to have one swapped £850 ish. So looking at trying everything else before that first… especially when a 30 year experienced jag specialist is saying they never go really. Cheers

 

It sounded like you purchased an incompatible coil pack. Try a NAPA 'Namco Echlin Ignition Coil IC599' for best results.

 

+1. If the fault follows the swapped coil / plug or injector, then it is the culprit. If not, focus back on #8 cylinder.

Cheers MrJaggy,

 

Again, I think that the Delphi coil failed for whatever reason. Just replace it with the NAPA coil, and be done with it.

 

thanks I’ve just done that and looks like it’s worked kind of… can you help me with the below:

I have just changed coil pack on cylinder 8. Cleared codes, EML gone and no codes off but car still in restricted performance. I only have basic obd2 reader to clear codes.. do I need to do a full hard reset via battery or do I just need a little time for computer to rework its brain etc.

 

If the vehicle is otherwise running fine (even with the restricted performance error), the basic obd2 reader should have cleared all of the codes (if it has that capability). As for me, I simply use a Foxwell NT510 Multi-System Scanner for servicing my 2005 Jaguar XJ8L, and it has served me well. If your obd2 reader can not clear all of the codes, then you would have to do a hard reset. Disconnect the negative terminal from the battery, wait a couple of minutes or so, and then reconnect the battery.

By the way, is that NSK spark plug the correct one for the car, and with the right gapping?

 

Are you needing the vehicle to pass MoT? If so, doing a 'hard reset' is going to cause the emissions monitors to not be in ready mode.

I don't see the available battery voltage listed in any of your posts. Use a voltmeter to read the available voltage across the battery terminals with the ignition in the OFF position for at least 30 minutes. If the voltmeter indicates less than 12.6 volts, the battery should be charged for five hours at 2 to 5 amps. Many of the random DTCs and instrument cluster warnings are the result of low available voltage.

 

Might try the tank method that connects to your fuel rail, & air compressor.
To clean your injectors while they are still in place.