Carbon buildup in spark-plug well

[Landboat G80]

Diagnosing a missfire issue, pulling plugs for the first time and see carbon buildup inside the well. Fresh plugs, so far they all look good (have only done driver side so far)

Just not sure if this should be cleaned and how to clean it. The mechanics that did my plug change ~150mi ago obviously left it.

 

[oddball]

uh, what? That's as clean as they can possibly be.

 

[Landboat G80]

uh, what? That's as clean as they can possibly be.

Proof of not doing my own maintenance in the past, I guess . Bit if a mechanical novice.

I just saw the black powdery deposits building up on the edges and assumed it was bad, plugs ended up being carbon fouled after 300mi. Ordered some new ones, will make sure they’re the correct gap and if miss-fire continues I’ll stop driving and replace the coils. After that it’s to the mechanic if no dice.

 

[stoopid]

Proof of not doing my own maintenance in the past, I guess . Bit if a mechanical novice.

I just saw the black powdery deposits building up on the edges and assumed it was bad, plugs ended up being carbon fouled after 300mi. Ordered some new ones, will make sure they’re the correct gap and if miss-fire continues I’ll stop driving and replace the coils. After that it’s to the mechanic if no dice.

Could just be some of the powder from the plugs when you removed them (falling off the engine exposed end when being extracted). I doubt that debris is spilling out directly from the cylinder as the plug is sealed when tightened down.

 

[Landboat G80]

Could just be some of the powder from the plugs when you removed them (falling off the engine exposed end when being extracted). I doubt that debris is spilling out directly from the cylinder as the plug is sealed when tightened down.

That’s what I thought too, I was wondering how the bell anything would get in there. That makes a lot of sense ‍:facepalm:

 

[oddball]

You mean that itsy bitsy black mark in the upper right of the picture?

That is, literally, nothing. It is extremely common for spark plug wells to damn near fill up with oil (not specifically on stinger - just any car made in the past 20+ years) because the seal on the coil separates the spark plug well from the inside of the valve cover as well as from the outside.

The big question: How in the world did plugs get carbon fouled in 300 miles? Are you running a wildly inappropriate tune? Unplugged O2 sensors?

 

[Landboat G80]

You mean that itsy bitsy black mark in the upper right of the picture?

That is, literally, nothing. It is extremely common for spark plug wells to damn near fill up with oil (not specifically on stinger - just any car made in the past 20+ years) because the seal on the coil separates the spark plug well from the inside of the valve cover as well as from the outside.

The big question: How in the world did plugs get carbon fouled in 300 miles? Are you running a wildly inappropriate tune? Unplugged O2 sensors?

The passenger side O2 connection was damaged, just got it replaced by the dealer. New plugs coming in tomorrow.

Thanks for the information, this is the first vehicle where I’ve done any amount of wrenching on myself, so I may ask stupid questions from time to time.

I did google it first, but there was a lot of conflicting information. I didn’t know what was or wasn’t normal so my best bet was to ask.

Thanks again for the info!

 

[oddball]

No worries. The learning curve can be steep and be prepared for some (mostly) friendly ribbing. It's usually best to find someone local to get you over the initial hump.
Where are you located?

 

[Landboat G80]

Right outside Houston TX