Cleaning fouled plugs
 

A while back a chevy/mazda dealer flooded my car. They refused to put new plugs in. Now I have been experincing some rough idle and power loss up top (running latest flash). I was wondering if it is safe to sand/glass blast iridium plugs? The car only has 20k on it. I want to try cleaning them before I go and replace the coils. here is a link to nkg on cleaning plugs :) http://www.ngksparkplugs.com/tech_su...s.asp?mode=nml

Personally, I would not sand blast any plugs. Used to be common practice, but it's been out of favor for some time. Particularly since the stuff that needed to be blasted off was usually lead deposits.

Try cleaning with solvent, like the NGK site suggests. If that doesn't work then try new plugs. Since you suspect the plugs, change those before messing with the coils.

With 20K on your car, you've already gotten a bit more than half the life out of your original plugs. A set from sparkplugs.com is only $80. ("Only" is compared to Mazda's list price.) So it's not that big a loss.

Ken

The function of the plug depends on the integrity of the surface of the ceramic insulator. What can happen with a fouled plug is that the spark can begin taking a path through the carbon; running along the surface of the insulator, and reaching ground down inside the plug. Over time, this arc will begin to eat into the insulator, and carbon from the deposits will actually be fused into the insulator material. This is known as a "carbon track", and cleaning will not help at that point, although it might allow you to visually identify the track.

Also, if the abrasive is too aggressive, sandblasting will also damage the insulator surface, making carbon tracking more likely.

I'd say solvent/toothbrush is your best bet, but it depends on how valuable your time is to you. 20K is not totally unreasonable time for new plugs, and you may save the trouble of cleaning, re-installing only to find that the plugs still aren't working well. Or even if they do, you'll still be due for new plugs at around 30K. Try sparkplugs.com for the best price.

Yes, yes, yes! This seems to be overlooked by most. As long as the deposits on the center insulator are a nice rich tan or light brown, and the contacts are in good shape, the plugs should be good to go. That is, assuming there is no unseen internal damage. I learned that from many hours of tuning motorcycles "back in the day".:D:

Well I gust got back from a drive and the response is much better. but when the engine gets hot I still feel missfires. I blasted them with a very light glass. Also the idle seems much smoother. Pics
http://i137.photobucket.com/albums/q...t/P1040105.jpg
http://i137.photobucket.com/albums/q...t/P1040109.jpg
http://i137.photobucket.com/albums/q...t/P1040108.jpg
http://i137.photobucket.com/albums/q...t/P1040110.jpg
I must have got some water in the boot also. the post was corroded.

Cool, didn't know you were in the sparkplug biness. I check you out next time I need a set.

I'm waiting for the improved clutch bracket :) . How is that coming?