Blue Powder Inside Distributor Cap

I opened my distributor cap and found blue powder around the distributor cap metallic points. I have a four cylinder, so I have four metallic points that the ignition rotor contacts while it rotates. The powder is similar that one finds around the terminals on an automotive battery.

I recently replaced the distributor cap, ignition rotor, ignition coil, and the spark plugs. The spark plug wires are old. Could it be the old spark plug wires?

I have a 1998 Honda Civic DX.

That’s called carbon tracking.

This occurs in distibutor caps when the high voltage from the distributor cap meets a resistance to the spark plugs. Usually caused from old plug wires.


Old spark plug wires are often the cause of ignition problems, especially in damp weather. If you’re replacing the cap you should also replace the wires.

Replace the wires, clean the powder from the cap, and drive on.

Just out of curiosity, what made you remove the cap and look inside?

This is just normal debris on an old and likely very due for replacement distributor cap. The rotor does not actually touch the contacts on the cap. There is a small air space (gap) and the spark (electricity) jumps across that gap. A little bit of pitting and eventually oxidation builds up as a result of this arcing of electricity from the rotor to the points on the cap.

My guess is your car runs noticeably better since you replaced these ignition parts.

“Just out of curiosity, what made you remove the cap and look inside?”

The area around the distributor cap was making an abnormally loud sound. Sure enough, there was powder!

It does run better. Thanks!