Hi Everyone,


So I'm doing a Tune up to my Jag since I can't drive it for another few months. I was just wondering if anyone had any experience with putting Iridium spark plugs in their 1995 xj6? If so would you recommend over oem champions? I put them in the rest of my cars just never put them in a Jag.

 

I did it and I had a rough idle
Threw OEM and bam fixed

 

Experiences are all over the board.

I've used both NGK Iridium and standard Champions and never noticed a bit of difference in the way the engine runs.

<shrug>

Not sure you can definitively gain anything from the extra cost of iridiums, though.

Cheers
DD

 

I wouldn't ... stay with stock

I've found the fancy plugs don't get you anything "special"

 

No differences here either. I went with the iridium on the theoretical chance that they may put a slightly lesser load on the fragile coils, but who knows...

 

That was my motivation as well....but, yeah, "who knows?". It would take the compilation of tons of long term data to come up with any useful conclusions, I'd think

Cheers
DD

 

After installing Iridiums in my 95 X300 3.2L, my car developed a rough idle, and would sometimes cut out while driving. Others have also noted similar symptoms, but not everyone by any means.
My mechanic searched for the problem...maf..throttle..
Problem went away when I replaced the plugs with Champions!
I don't think my mechanic believes that was the cause, still!

 

Hi Jag Enthusiasts,

This is my first post and this forum has helped me immensely in fixing my 1995 Jaguar XJR.

Here is what I had to face with the following:

- Rough idle – Changed spark plugs to RC9YCC versus the Iridium type plugs I had installed. I should have used RC12YCC if my jag has idle problems, but stuck with Champion RC9YCC and so far going on 2 years all is well.

Other issues exibiting similar rough idles and stalling on my Jag:

- Dirty throttle body – had it cleaned and rough idle and hesitiation went away
- The Engine Harness connector was cleaned and contact enhancer was added to the terminals. The connection was rusty causing wild high reving idles and almost stalling scenarios where I had to keep the idle at 1000 by holding left foot on brake and right foot on gas.
- Harmonic Balancer was replaced because it had cracks and was producing idle problems.
- Smoke test was done on exhaust and found the exhaust clamps behind the CAT converter and at the muffler are leaking. This was fixed by a muffler shop.
- Changed original air filter to a K&N then had alot of rough idles and stalling. Later found out this Jag does not like the oil sprayed K&N filter so I returned it back to stock after cleaning the MAF with MAF cleaning spray. The rough idles went away.
- Faulty Ignition Coils - were found and changed them all at once. I purchased the Prenco 36-8082 coils made in China and my rough idles and at times Check Engine lights was resolved.

My Jag has not been the best behaved but sure love the clean lines it has.

 

Good to hear from you and welcome aboard.

How low ago did you install the Prenco coils? As you probably know there has been lots of discussion about off-brand coils.

Cheers
DD

 

Sorry double post not sure what happened.

 

I purchased the Prenco ignition coils with the white tops shown on the image on the left 2 years ago from the date of this post. I started to feel slight rough idles on my 1995 JAG and caught a 1 second glimps of an check engine light and knew immediatly it is an ignition coil over issue.

Due to the knowledge base on this forum I learned I can remove my ignition coil cover and start my 95 JAG and watch for a lighting show ontop of the ignition coils. Sure enough I saw cylindar #6 giving me a light show. I then removed the coil and swapped it with cylindar #5 and the light show moved with the coil.

As the image shows below I purchased the Prenco ignition coils on the left with the white tops. Two days ago I went to purchase one more to fix my cylindar #6 ignition coil light show and found the tops are now black and come with gaskets.

I am not sure what the gaskets are meant to do. I have run my ignition coils without one and also when it was given to me it had no gaskets.



Now that I am active on this board. I will work on taking pictures and video to post my adventures with my JAG.

I have done this with my Plymouth Prowler and Saleen I used to own and was very active with these vehicles.

Check out my sites for these cars.

Plymouth Prowler Site
Prowlerexcitement.com (Your source for Prowler Roadsters)

Saleen Site
http://www.saleenexcitement.com

Till next time.

 

That's an interesting read by dpena; I was wondering if different standards of fuel around the globe alter spark plug performance' Here in N/Z the fuel is imported I think from Singapore and I am using when I can get it BP 98 octane but sometimes I can only get 95 octane and I certainly notice a drop in performance and a rougher idle with the Champion RC9YCC. ihave now changed to NGK-BKR7E and have better performance all round

Cheers Ray

 

I installed these in June, 2011....or 60K miles ago, no problems yet (Orig coils AFAIK and car has 145K+ or at least, I haven't changed a coil since I obtained the car in 2010 with 63K on the clock):
NGK BKR6EIX Iridium IX Spark Plug in

 

I have used the following plugs and have had hit or miss performance ranging from rough idles to poor hesitation.

I have used these with poor performance:
Autolite-AP3924



I later changed to these with poor performance:
NGK_V-Power_Copper_Spark_Plugs_BKR6EK



In the end the ones working best with no performance issues were the Champion RC9YCC

 

This is no doubt a dumb question but why have the NGK's got that brown staining at the bottom of the ceramic?

Mike

 

According to the Engine Service Manual:

Champion RC9YCC (except North America, normally aspirated engines)

Champion RC12YCC (North America, for normally aspirated engines only)

... the 12 being a slightly hotter plug.

 

That's known as "corona stain". It's the result of the corona spark ... the gap between the insulator and "nut" and a spark traveling up the plug.


??? The "other brown stuff" on the far right plug could be from the person's oily finger or possibly oil leaking into that spark plug bore???

 

I would definitely use gaskets. If you don't get them with the coils you can make them from the back of a tablet. I did that for a while and it worked fine. I also believe in insulates the coils from the magnesium cove somewhat which is important in keeping down the electrolysis effect. In fact you should also put electrolite grease on the gaskets. That can't hurt and may help preserve your cover a little longer. Those covers are now $750.

 

Hi EZDriver,

My jag is running fairly smooth and began to notice a slight rough idle when coming to a stop light this week.

I decided I would check the ignition coils at night to see if I saw flashing arc on the top of the ignition coils and sure enough I saw it happening on Cylindar #1. It is only happening on rare occasions and had to sit there and watch my engine run for about 10 minutes and noticed the light show for a second or two then it stopped.

Something is killing my ignition coils. Not sure if the engine heat is hotter than usual. I'm still paying close attention to this to see if I can figure out what is going on.

I will follow your advice to see if my ignition coils last longer.

 

Let us know if you discover anything. You're not the first to have problems with aftermarket coils. Either there's a quality problem or some sort of specification/design issue with the aftermarket coils where the coils and the car don't tolerate each other very well.

If you buy any more coils I suggest going with the true OEM type. SNG Barratt is selling them.

Cheers
DD