I just wanted to report the failure of an IK22 Denso Irridium spark plug in my friends supercharged S2000. Yes, the car is tuned and not running lean, so I don't suspect detonation was a problem. Due to forced induction, high cyclinder pressures may have contributed to this failure.

The presenting symptom was a ticking sound, very similar to the sound of loose valves, but slightly louder. I initially suspected a bent valve, and we were relieved to discover it was only the spark plug. However, others have reported breaking off the ceramic and having that piece damage internal engine components. So if you're running forced induction, you'd be well advised to check the condition of your plugs more regularly than you may think necessary.

In the following photos, you'll note that there is a black ring at the junction of the upper ceramic and metal jacket of the plug. This was where combustion gasses had forced their way between the ceramic and metal parts of the plug. The coil pack was also slightly burned, but worked fine with the replacement spark plug. Note that the first and second photos are of the same spark plug and that the ceramic was free to rotate within the metal. A second spark plug was also exhibiting the black ring, but the ceramic was not freely moving yet. The third photo shows an unaffected spark plug. The failed spark plug was in the #4 (rear) cylinder.

 

You lucky dog good to see that it did not do in the engine
Will you be trying another brand of spark plug?

 

Thanks for the heads up - I was running IK27 's at the last chin event and the car was experiencing heating problems if you remember and was running rough on the way home and I pulled my plugs and had one fouled plug and put back in my NGK 7173's and it runs great now - I won't be putting the Denso's in again!

 

We had a Denso fail at Dyno day. Broken piece of ceramic went into the engine and scored the hell out of the cylinder.

 

I would like to thank CoralDoc for his help. I was releived to find out it was just the plug (Denso Iridium Ik22) but suprised at the same time. I have never had a plug fail like this. They only had about 6K on them. I am currently using NGK copper plugs but I will be switching to the NGK V-Power Copper Racing next oil change. I was using these before and changing them every 3K. Thought the Denso would last at least 10-15k. Guess not. I had heard only good things about Denso. Don't think I am running lean since I just pulled the code - P0172 - Fuel system on bank 1 was too rich. This happened after 1st tuning session as well.

Has anybody had these plugs fail?

 

I had some IK24's fail. Two of them lost the ceramic insulation around the center electrode and had some oil on them. I had a compression test done just yesterday and it seems fine. I've since replaced them with IK27's and am crossing my fingers.

 

Yep. Talk to Joe.

Too many failures and scary stories with Denso IK plugs and FI S2000s. I'm sticking with NGK.

 

After running the Denso IK-24 for about year, the engine developed a high rpm miss. I pulled them and they didn't look any different but then, I caught it very early. I put in the NGK V-Power coppers. The car has been running fine since. I don't think I'll be using Iridium plugs from anybody. The copper plugs are cheap enough, I can put new ones in every few thousand miles and still not break a sweat.

Technically, at least in a NA engine, Iridium plugs should be the last plug that engine should ever need. Platinum plugs are supposed to last 100,000 miles or longer. Iridium plugs should last much longer. I've got Denso Iridiums in our PT Cruiser (NA) and the car has been trouble free for nearly 2 years. I'm hoping I'll never have to do plugs again on that car. I just don't think Iridiums are such a good idea for F.I.

 

xviper, I do have similar problem. I have IK24. it's been there more than 2 years. about a year ago, it started to develop 8000 rpm bog. RPM will rise but slower than below vtec range. do think it's related? I just went to FC05 and dyno'd it. the dyno guy also recommending switching it to copper tip.

cheers,

 

How do the plugs look? Do they tell a story of what the A/F has been like?
The only way to tell if it's the plugs is to try new ones. Nothing beats the good ol' standby copper plugs. Go with the V-Power NGKs. I think the old number is "7173" but you can cross reference using that number.
If new plugs don't fix your problem, then look towards the MAP sensor and the Honda TSB for it. This too, could be the cause of your symptoms.