Honda K24 engine with discolored ignition coil

[Mikhail]

Hi All.
I decide to perform some engine maintenance of my old Honda Accord.
One of the ignition coil is a different color then others. Any idea what that means? Loose spark plug or something else? Do I need to replace that brown coil?
Also spark plug that was installed with the coil in question, has some brown residue on porcelain part. I am referring to the first spark plug from the left, see picture.
Any ideas/advice?!

 

[AndyCBR]

Just a guess but maybe that circular valve cover gasket for that spark plug wasn't sealed correctly and seeped oil on that one plug well.

You don't say how many miles you have or the year (which would be helpful info to diagnose over the internet) but I would guess you are nearing 100k and the vehicle is older.

While you're there it makes sense to do a valve cover gasket and new spark well seals (if they are separate from the valve cover gasket itself).

Hope this helps.

 

[Bogie1632]

Likely was a loose plug letting some combustion past. Not at all uncommon. You can test coils to see if they are good or not. Kinda depends on overall condition and test before I'd replace it. Any cracking, hardening, tests bad, etc get a new one. Check the rest and while your at it. Some, depending on how long they ran that way, can be cleaned up before you shoot the parts cannon at it. Just from the pics alone, personally, I'd likely replace it. Looks like it got plenty of heat on it for a while but it's in front of you and only a pic for me.

V/R
Bogie

 

[Super Mech]

I’ve seen this before on this and other engines. I never came up with an answer other than the possibility of Corona discharge like what happens on high voltage power lines. It can happen without electrical breakdown.

 

[Mikhail]

Just a guess but maybe that circular valve cover gasket for that spark plug wasn't sealed correctly and seeped oil on that one plug well.

You don't say how many miles you have or the year (which would be helpful info to diagnose over the internet) but I would guess you are nearing 100k and the vehicle is older.

While you're there it makes sense to do a valve cover gasket and new spark well seals (if they are separate from the valve cover gasket itself).

Hope this helps.

I apologize for incomplete information. This is my 2004 Honda Accord with almost 350 000 miles. Not my daily driver anymore, but it’s always been zero problem vehicle for me. Valve cover gasket is leaking and I have new gasket kit in the garage. I also replaced vtec solenoid gasket.

 

[Mikhail]

Likely was a loose plug letting some combustion past. Not at all uncommon. You can test coils to see if they are good or not. Kinda depends on overall condition and test before I'd replace it. Any cracking, hardening, tests bad, etc get a new one. Check the rest and while your at it. Some, depending on how long they ran that way, can be cleaned up before you shoot the parts cannon at it. Just from the pics alone, personally, I'd likely replace it. Looks like it got plenty of heat on it for a while but it's in front of you and only a pic for me.

V/R
Bogie

Just tested resistance with multimeter.

 

[engineer2]

What year? My 2010 Fit developed a loose plug at 40,000 miles and the coil looked like yours. Simple fix; tighten the plug to spec. The symptom? Exhaust smell from the air vents.