Why is one spark plug black

[dsmfreak95]

I was checking my spark plugs the other day and I noticed that the 3rd one( from left to right) was kind of black, and the other three looked good. I have a dynatek coil on plug set. I was wondering what's going on. I've also been haveing a problem with the car sputtering. Could the third coil be going bad or what?? Ive really only had the one the car about 8-9 months. Any help would be great. Thanks

 

[Kickerbeast]

Post a pic if you can. It could mean different things. Could be carbon from that cylinder running too rich, or it could be oil from leaking valve seals. A pic would help greatly. Either way, whatever is causing this is likely causing your sputtering problem

 

[95blackGsTurbo]

Since your car is sputtering, I would suggest checking compression on that cylinder, ohm out the injector and check the coil packs resistance as well. Injectors should be between 2-3ohms. If you let me know what kind of coils you are have I can get you the specs on them as well. Definitely sounds like that cylinder is misfiring for whatever reason.

 

[dsmfreak95]

Post a pic if you can. It could mean different things. Could be carbon from that cylinder running too rich, or it could be oil from leaking valve seals. A pic would help greatly. Either way, whatever is causing this is likely causing your sputtering problem

I'll try and post one this afternoon, I don't think it's running rich though because the plug didn't smell like gas.

 

[Kickerbeast]

doesn't have to smell like gas. If it is just a little rich it will get carbon build up. If it was rich enought to smell like gas, then it would like be completely fouled and wouldn't fire at all. Then you would have a constant miss.

 

[crimsondragon]

Was that plug properly gapped?

 

[SBR Joe]

Since your car is sputtering, I would suggest checking compression on that cylinder, ohm out the injector and check the coil packs resistance as well. Injectors should be between 2-3ohms. If you let me know what kind of coils you are have I can get you the specs on them as well. Definitely sounds like that cylinder is misfiring for whatever reason.

X2. i had a headgasket pushing an ever so slight amount of water into one cylinder and the plug was black as night. Dry as a bone, just enough to blow the spark out. Could also be a sticky injector, but start with a compression test. If that cyl is lower than the other ones, you know where the problems lying then.

 

[dsmfreak95]

Was that plug properly gapped?

Yea because that's the reason I took it out in the first place. I made sure they were all tapped at .028. If I were to change the spark plug out would it run better for a little while?

 

[Kickerbeast]

Depends on what exactly is causing the issue with the plug.