2G fouling just one single spark plug in cylinder 3

[Nick G]

car runs great for a day or two but constantly fouls plug number 3. I replace it and runs great again. brand new plug wires and is tuned correctly. just can't figure why its just cylinder 3.

 

[2gmitsueclipse]

car runs great for a day or two but constantly fouls plug number 3. I replace it and runs great again. brand new plug wires and is tuned correctly. just can't figure why its just cylinder 3.

Post a pic of said plug.

Fouled by fuel: Injector may be faulty (sticking open)

Fouled by oil: Perform compression test followed by leak-down test to track the issue.

 

[Nick G]

I will take a pic when I get home. It's fouled by oil. The car does 150 compression across the board. But smokes bad. I was thinking rings?

 

[2gmitsueclipse]

Next up, leak-down test.

If you want more information about either compression or leak-down testing, read the following:

http://www.dsmtuners.com/threads/compression-and-leak-down-testing.338152/

 

[donniekak]

How old are the valve seals in the head?

 

[Nick G]

just rebuild the head with everything new.

 

[donniekak]

Who rebuilt the head? There aren't very many ways for oil to get into just one cylinder. Either a guide/seal issue in the head, or a cylinder wall/ring issue in the bottom end.

 

[Nick G]

I had a local machine shop do a valve and deck job. I installed it with felt pro head gasket and new arp studs and valve seals. the last thing on the list is rings which explains the smoke. Could I just re ring the pistons by dropping the oil pan or would I have to pull the motor?

 

[donniekak]

The head has to come off to re-ring, as well as the oil pan. It's best to pull the engine so you can be sure to clean out all of the honing grit when you are finished.