I just changed the plugs in the '86 today. What a bitch getting to that forward one on the passenger side! I'd have left it in if I hadn't broken it when attempting to remove it with a socket and universal joint. It was only then that I employed an open end wrench to the socket that I was able to remove it. Anyway, here's a picture of the plugs I took out. They're black and sticky - does this mean I'm running rich or burning oil? If it is running rich, how does one adjust the fuel/air mixture anyway? It isn't smoking or missing - in fact, it runs great. Thanks for the advice folks.

 

Here are a few good articles about spark plugs and the meaning of various types of residue.

http://www.ngksparkplugs.com/techinf...q/faqread2.asp
http://www.sentra.net/tech/sparkplugs.php


The operating temperature of the plugs have a lot to do with their overall performance. Beyond that, it could be, as you suggested, the presence of oil in the combustion chamber - either slipping past the rings or the valves.

Best wishes!

Rick

 

I think I'll check the new plugs after a few hundred miles and see how they're doing. Very helpful, thanks Rick.

Shawn

 

What plug numbers are you using? Are they black and wet or chalky looking? If they are kinda wet looking or brownish looking, its oil residue. If it is chalky, its a rich condition and there is no "adjustment" on TPI unit. Could be fuel pressure regulator, O2, MAF, MAT. Check codes and fuel pressure. [8D]

 

I replaced the Champions with Bosch 4208's. The Champions were just kinda black and sticky, mostly around the threaded edges and not on the spark contact itself.

 

I neglected to ask what mileage your engine has on it. You might need a little hotter plug on a higher mileage engine. Fuel injected engines will burn oil a little more effiecient than carbed engines and you might not can see it from the cabin. Valve guides could be a little worn, also. Have someone watch your tailpipes on a cold start and also follow behind you and watch under acceleration. I'm a firm believer in Delco's Iridium plugs as far as durability. They last 70 - 80 k miles with hardly any deteriorzation. [8D]