Plug question
Thread Starter
4th Gear
Joined: Jan 2023
Posts: 4
Likes: 3
Plug question
I did my cold air intake last week and I brought my car to corvette center in CT to do my American racing headers and catted x pipe. My car has 19k miles and they said my plugs are black like charcoal. What would cause that? I trust them and they do great work and I’m not questioning them but just wondering the reasoning how they would get like that with a car in stock condition
Le Mans Master
Joined: Oct 2014
Posts: 8,662
Likes: 2,721
From: Atlanta GA
#1 you can't read a plug by just pulling it out of the head , you have to make a hard pass , let off gas , and shut motor down ASAP #2 , LT direct injection motors from the factory run rich , as evidenced by the black tail pipes
If it's running good , all 8 look the same , don't worry about it . Just take it out and run it hard once in a while
Dave
If it's running good , all 8 look the same , don't worry about it . Just take it out and run it hard once in a while
Dave
Pro Mechanic
Joined: Oct 1999
Posts: 3,905
Likes: 1,440
From: South-Central Coast California
#1 you can't read a plug by just pulling it out of the head , you have to make a hard pass , let off gas , and shut motor down ASAP #2 , LT direct injection motors from the factory run rich , as evidenced by the black tail pipes
If it's running good , all 8 look the same , don't worry about it . Just take it out and run it hard once in a while
Dave
If it's running good , all 8 look the same , don't worry about it . Just take it out and run it hard once in a while
Dave
And the "black tailpipes" people see? They're totally useless as a measure of whether or not the engine is rich or lean. If you look at a calibration file from any direct injected engine in a Corvette, you be surprised that DGI engines run more lean that port-injected, throttle-body-injected or carbureted engines.
