Spark plugs - I assume this is normal

[qship]

Hi all. Had the car serviced today and the dealer returned the old plugs. Interesting (well to me anyway) that all the plugs had two electrodes with a brownish tinge and one which was black. I assume the brownish side faced the direct injector and the black did not. Normal?

[Dackelone]

My plugs didn't look quite that black as yours - when I changed my plugs at ~40K miles.

Do you have a tune?>?

BMW NA says the change the plugs every 45K miles. Tuners say every ~20K miles or so.


Here is what my plugs looked like...




135i Spark Plug replacement DIY...
http://www.1addicts.com/forums/showthread.php?t=602804

[MightyMouseTech]

The black on the plugs really does not mean anything. Just shows that there were not fully warmed up before they were replaced. Basically, tech went out to lot, started car, brought into shop, changed plugs and put it out.

[Lester]

A little wipe with #400 grit sandpaper and they'll be as good as good as new! How many miles on them?

[bmw1racer]

Originally Posted by qship

Interesting (well to me anyway) that all the plugs had two electrodes with a brownish tinge and one which was black.

I count three electrodes... Or are you talking about something else?

[Dackelone]

Originally Posted by bmw1racer

I count three electrodes... Or are you talking about something else?

He is saying that ONE out of the three electrodes is black.

[bmw1racer]

Originally Posted by Dackelone

He is saying that ONE out of the three electrodes is black.

Doh.

[Kiwi Peter]

Originally Posted by qship

Hi all. Had the car serviced today and the dealer returned the old plugs. Interesting (well to me anyway) that all the plugs had two electrodes with a brownish tinge and one which was black. I assume the brownish side faced the direct injector and the black did not. Normal?

Normal
The fuel we have here in Australia is not the same as you US and Euro guys, so the plug colour will be different.

[qship]

The plugs have done about 25000km with a Cobb tune for about half of that. I replaced them in an attempt to fix a rough idle issue I have had since day one of ownership in April 2008!.

[drjekl]

Originally Posted by qship

The plugs have done about 25000km with a Cobb tune for about half of that. I replaced them in an attempt to fix a rough idle issue I have had since day one of ownership in April 2008!.

Did it fix it?

[froop]

You've only done 25,000kms in 5-6 years?

[qship]

Originally Posted by froop

You've only done 25,000kms in 5-6 years?

Nah - These are the second set of plugs I have changed.

[johngrossi]

Originally Posted by Ian///M

+1, look a bit dark.

Here's a guide

This is a very useful chart, I remember seeing this in my old textbook

[qship]

Originally Posted by drjekl

Did it fix it?

Short answer - NO!

Car is definitely smoother overall and idles a bit better, but still hiccups and skips occasionally, particularly when cold.

[drjekl]

Originally Posted by qship

Short answer - NO!

Car is definitely smoother overall and idles a bit better, but still hiccups and skips occasionally, particularly when cold.

Well my idle and low speed hiccuping/lurching was rectified with new pre cat lambda sensors and vanos solenoids (like yours the plugs made a difference but didn't eliminate it...