OK...I haven't dealt with this in years in a car, but...I replaced the plugs in my 2000 JK8 yesterday (new Bosch Platinum +4 plugs all the way around). Now, I get a ticking (which is definitely ignition-related as it speeds up/down with engine RPMs) from the FM stereo (but not from CD or cassette). I know resistor plugs used to be a solution to this, but I've not heard of this problem with newer cars. Anyone run into this or have some suggestions (outside of dumping the new plugs)? Does the XK8 have some sort of suppression system that might have failed?

 

I had that problem in another vehicle that I had, and it turned out to be a connection that was not secure, something was not plugged all the way in. I think that that little spark or lack of shielding was causing the noise. After I snugged it up really well the noise went away. As I recall I think that it was one of the wires to a hard to reach plug that was not all the way down on the plug.

There are some real Jag experts on here who may have better info, but, you could check out the connections until you get some additional info.

Good luck, I know how annoying it is.

 

I think Kevin's got it. It's possible something is getting to the radio "through the wires" but more likely something on the high-voltage side of things is radiating. A poor connection of some sort or perhaps a bad plug wire would be prime suspects.

A test to confirm this is to raise the hood (aka bonnet). The clicking should get worse if the problem is in fact on the high-voltage side.

Good luck.

 

Kevin's suggestions are good...first make sure all the spark plug and boots and coil connectors are snug, and that the plugs were torqued correctly.

I would add, check the power antenna in the trunk for a loose ground connection (braided wire). If it is not loose, remove the ground connection and clean the lug and the contact area with some fine sandpaper and refasten.

 

Appreciate the insight guys! I'll open her up tomorrow and check plug torque and obviously re-seat the coil packs very carefully. Opening the hood seemed to not make any difference tonight in the "ticking" through the stereo. I think I torqued the plugs at 18nm...is that correct?

 

Actually it would not hurt to open the hood at night.... If it is dark outside and your car is running, if you are arching a wire or ground, you could see it. It could be that simple and God knows I am always looking for a reason to go out and just look at mine or should I say the Wife's....

Da Count

 

You know, it's funny that you say that, because after I replied, I remembered when this incident happened to me.

I was driving from New Orleans to Atlanta and at around 6:30 PM, my car started missing and running really bad, having a hard time making it up the hills. It was winter, so it was dark out. I stopped on side of the road and opened the hood and it looked like a laser show underneath there!
There were arcs and sparks going everywhere.

I managed to limp into a small town outside of Montgomery and managed to find an Auto Parts store that did not close until 8:00 PM. I bought a new set of plug wires and put them in. The car ran fine all the way to Atlanta, but I had that sound in my radio, just like in the OP. I had put the cables in in a real hurry and suspected that I had not done a good job, so the next morning is when I found the one that was not really pushed all the way down. I secured it and then the interference in my radio went away.

This was in about 1987. Funny how things come back to you, even after all those years.

 

My first car was a 69 Camaro RS/SS 396 Muncie M22 Edlebrock Tunnel Ram with 2 holley 600 center squirters 4.11 gears... Did all my own work,,, made my own spark plug wires. First time I did it the car did not run right and it was getting late, I got pissed off... an hour or so later I go out it's dark and late,,, I had the hood up and started the car,,, It was a light show,, fixed it next morning in the light,,,,

So it was a thought ,,, Tell me what you see....

Da Count

 

The moving of the plug wires could have exposed a week spot in one of the plug wires, but I would check the connections first. I assume it is a tick from only one cylinder your hearing not all 8. That would be more like a buzz.

 

No! The correct torque is 25-29 Nm

 

I'll do the torque and coil re-seat check this afternoon and if that doesn't do the trick, I'll wait until dark and see if I get any "lights". Thanks for the thoughts, guys, and appreciate the new torque number WhiteXKR. Last week, I swapped out the secondary tensioners, along with new gasket/o-ring sets. I wonder if insufficient torque on the new plugs plus new gaskets has one of the coils "sitting too high" and not making good contact on that plug. I AM only hearing a tick, which I agree, sounds like a single cylinder issue. More later today. Thanks Guys!

 

We don't have plug wires. So if the plugs, and coils are torqued correctly there really shouldn't be a concern with a loose connection - the spring in the boot should compensate for the coil to plug connection you just need to be sure the plug to head is tight, and the coil is not loose.

My first question would be what type of plugs did you use? Some plugs are resistive to cut down on radio interference. If you got some plugs that claim to be high performance, they may be low resistance to try to get more energy to the spark.

The second thing would be to check those springs in the boots to make sure they areproperly in place to contact the plug tips.

Checking the antenna grounds as mentioned is also a good idea to clean up AM reception.

Just re-read the original post and see it was Bosch platinum +4s. I'm not a fan of Bosch plugs - I will never use them again. Especially if in an XKR or any forced induction engine. If you still have them I'd clean up the original plugs and reinstall them to see if that fixes the noise. Then consider a different set of plugs, personaly I like Denso Iridiums.

 

Put old plugs back in and see if it is still there...if it is, keep hunting. If not, trash the platinums and put iridiums (NGK is my choice) in it like recommended in the manual and the original plug type.

 

OK - apologies for not getting back to this until tonight. I ended up in DC on business for 3 days and just got back last night. I believe it was a coil that apparently didn't seat well when I replaced it after the spark plug job. I pulled the coils and torqued the plugs down to 27nm. After examining each of the coil springs with a flashlight, one of them on the passenger side looked like it had been bent almost at a right angle about 1/4 inch up, probably shortening it just enough to cause an arc I'm guessing. I got it straightened back out and put everything back together. Wah-lah...no tick! I'll watch it for a while, and if it acts up again, will swap in a new coil. Thanks for everyone's suggestions and assistance with this!

 

Glad you got it fixed. Sounded like a single bad connection to me.