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Discussion Starter · #1 ·
i just changed my plugs about two weeks ago and noticed that they were heavily coated with black dust. usually they are not bad. i changed them later than i usually do, but i dont think that is the case. i did a search on this already, but came up empty handed. would being to lean/rich cause this??
thanks,
mike
 

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To much fuel. All Preludes run rich from the factory. Trust me, its way better than checking plugs, only to find them coated with a snow white color. Or when a chunk of your plug is missing, also bad. That called running to much nitrous without reatarding the timing. ;)
 

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yea mine were black like a mofo when i pulled them ~1K miles ago....the only thing you should be concerned about is if theres oil on the white part of the plug all the way up...
 

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Discussion Starter · #4 ·
MugenPoweredLude said:
the only thing you should be concerned about is if theres oil on the white part of the plug all the way up...
what would that mean? for the last few times that i changed my plugs they had rust colored streaks going up the white part, just a little bit. this time, they were just white, but with the carbon build up.
 

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Discussion Starter · #6 ·
i only use 91 octane (unless i can find higher)
 

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jitsu666 said:


what would that mean? for the last few times that i changed my plugs they had rust colored streaks going up the white part, just a little bit. this time, they were just white, but with the carbon build up.
if you have oil on the white part of the plug more than likely your spark plug gaskets are gone...and i believe you have to pull the valve cover to replace them...but dont quote me on it...i forgot:rolleyes:
 

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MugenPoweredLude said:


if you have oil on the white part of the plug more than likely your spark plug gaskets are gone...and i believe you have to pull the valve cover to replace them...but dont quote me on it...i forgot:rolleyes:
sounds like you are talking about the upper portion (part the spark plug wire boots go over) of the plug.

the black stuff on your electrodes are just carbon deposits from running rich. Take a flame and hold it on some glass. The glass will turn black... If you are "reading" your plugs then you want to check and see where the heat band is on the ground strap and the color of the porcelon (sp) on the plugs. Also you want to look for plug deterioration from detonation among other things.
 
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