View Full Version : Look at my spark plug...

12-13-2005, 05:38 PM
I pulled my plugs (NGK BKR6E) last night and replaced them. I wanted to see what they looked like after 5,000 miles:


I have what seems like a lot of black soot coming out of my nice new shiney Borla exhaust tips. I have been emailing AWE suspecting that my car is running rich due to the 5 bar FPR I installed in August. The car seems to have been running rich ever since.

I did some searching on the internet today and found some really good spark plug reading information. According to what I've read:

1. The ground strap is showing signs of excessive heat. The blue line is more than half way down the ground strap. This means I should move to a colder plug (heat range 7).

2. The center electrode and porcelain show the car is not predetonating. The coloring is what is expected for most motors.

3. The base ring is very black and sooty. This means the motor is running rich. Not so rich that it's a problem, but the motor is losing HP while still capable of max. torque. The article said this is how the tail pipe will look also (true in my case).

4. The base ring also has flakey dried soot. This means that the spark plug was too loose in the head and some air has been pushing and pulling past the threads. (This is true because I almost could have removed them by hand even though they were properly torqued at install.)

This is the first time that I have done this and I am not by any means any type of authority on anything. I could be slightly misreading the plugs, but this doesn't seem to be rocket science. I'm going to run the new plugs for the rest of the week, then switch to the NGK BKR7E's and see what happens with them (for heat range markings).

What do you think?

12-13-2005, 05:40 PM
They dont look bad, ive pulled mine and the whole tip was a solid black.

12-13-2005, 05:42 PM
You have to understand that you're running too much hot air for the stock smic. That's why your plug is reading "too hot". It's ok for your situation. In regards to the rich reading, that black ring is normal for a safe tune. If you want to see what it's running on boost you have to cut the engine off at that point. The reading off the ceramic insulator is only good for the last few ignition cycles which i assume were at idle.

Forgot, overall I would give a thumbs up.

12-13-2005, 05:53 PM
bitterchild: Yes, I was at idle. I was planning to do the spark plug read as you had suggested to me the other day, but the weather here in WI sucks lately.

Do you really think the SMIC is a problem when the high temp around WI has been at most in the mid 20's for the last month? I'd buy the argument in summer, but now?

The ceramic read was really not important to me. I've never heard anything like pinging with my car. It's not what I was looking for is what I'm saying. Just regurgitating my latest knowledge input [;)]

So, do you think I should try a colder plug or not? They're cheap, so I thought I would give it try.

12-13-2005, 06:46 PM
o mine was worse the first plug change i did when i got it from the last owner ...

12-13-2005, 06:52 PM
you could try the bkr7e but i would be prepared for some bad warm up performance... it'll take longer to come up to self cleaning temps

12-13-2005, 07:22 PM
Looking like your running way lean, the white tip shows its trying to burn everything in the cycle to even out the air/fuel ratio. give that bad boy some more fuel.

12-13-2005, 07:36 PM
what white tip are you referring to?

12-13-2005, 08:10 PM
turbow8: I don't think you've got that right. I found a lot of good info with some simple google searches. It pretty much goes with what I'm stating.

bitter: I'm going to email this pic to AWE just to see what they say. I really like those guys. Very knowledgeable and quick to respond EVERY time. I'm satisfied that the car is probably running good. Tuned to the safe side of A/F which in the end is most likely best. I suppose I'll just have to find a good way to clean those beautiful Borla tips...

BTW: I still plan on doing the spark plug test you suggested. I'm curious enough and would like to see the results.

12-13-2005, 08:42 PM
That looks like every spark plug I've ever pulled from a good running engine honestly. Looks fine to me :)

12-13-2005, 08:46 PM
After changing plugs in many a car... those look just fine to me.