What causes this?
What causes this?
Post Fiend
Joined: Nov 2002
Posts: 9,987
Likes: 7
From: Memphis, TN
What causes this?
The inside back cover of the Haynes manual has color pics of spark plugs for diagnosis. If you get one, you'll see YOUR spark plug in the 4th pic down on the L side. 
It says the ash buildup comes from burning oil & fuel additives. It recommends changing fuel brand 
& valve guides 
.
It says the ash buildup comes from burning oil & fuel additives. It recommends changing fuel brand & valve guides .
Elder User
Joined: Dec 2002
Posts: 738
Likes: 2
From: McChord AFB
What causes this?
thats ash deposits, try a cheaper easy way first. Try just richening your mixture a bit. Becouse it looks like you could have a lean running problem too. If that dosnt fix it then im afraid it could be the valve guids as stated.
Hotshot
Joined: Oct 2002
Posts: 18,488
Likes: 22
From: The Big, Oregon
What causes this?
That's oil, as near as I can tell. Might be blow-by getting sucked in by the pcv valve. EFI engines normally run lean like that, so I wouldn't worry about that. Since only one plug has that buildup on it, I don't think it is fuel additives. Pull yor pcv valve off with the engine running, and see if anything comes out. If just a little whiff of smoke is coming out, that's ok. But if it's puffing away, it could be rebuild time.
