Hey all,

I was reading up on Spark plugs today since I pulled them due to sluggish throttle response and noticed my gaps had opened opened up by about .005. I also noticed that plugs 7 and 8 were wet and smelled like gas and had the widest gaps. Anyway, I ran across this article and it looked interesting, seems to be a snippit from a book:

http://www.4secondsflat.com/Spark_plug_reading.html


Enjoy!

 

thanks,aim4um this is pretty cool.now i could see how f***ed up my truck is running,dam and i just changed the pugs too.

 

I just checked a plug, and it looks like i have a rich idle and a lean WOT. From that, I think that after 145K my fuel pump needs to be changed. Thats my project for next weekend.
Iprinted that article and put it into my truck maintenancebinder.

Great read!

 

Keep in mind this is a carbed engine they are talking about, but most of it should still apply.

 

Interesting...I am going thru plug hell right now with one snapped off in #4.
However I did see what you were talking about.
All 7 plugs that I was able to pull out intact had a gap close to .050 instead of being at .040. Ithought it was a bit odd. I did have the rear 2 which would be 7 and 8 that were still a bit wet and gassy too. Hmm...

 

Plug gaps will open up over time. I run an MSD setup that tears up plugs pretty quickly so I check them about once every 7500 miles or so. I'm still not sure what to think of the wet plugs though, the burn pattern seemed okay, so IDK if I should be that worried. Perhaps I killed the engine after the injector sprayed but before the plug fired.