Petersubaru Posted May 1, 2011 Share Posted May 1, 2011 wanted to change out the plugs, only to find that I had 2 Denso and 2 NGK's ..all 4 plugs are correct for the 1990 loyale..installed on each side 1 ngk and 1 denso and then drove 1 hr ...out of curiosity I pulled the plugs and the denso were grayish in color through out while the ngk's were more whiteish with a greenish colored ground strap..switched them around and drove another 1/2 hr..pulled the plugs once more..basically no change to the plugs except that the green color was a little darker ..spark plug charts make no mention of this greenish tint..any ideas..timing, or are the plugs to hot?? Link to comment Share on other sites More sharing options...
87.5ea82txt Posted May 1, 2011 Share Posted May 1, 2011 Not sure about your case, but green usually indicates oxidation of copper. If you want a reliable indication of your cars fuel/air ratio, clean the plugs and do a full throttle run in 3rd and kill the engine before lifting your foot off the pedal. Link to comment Share on other sites More sharing options...
87.5ea82txt Posted May 1, 2011 Share Posted May 1, 2011 Better yet, I would replace them before testing again. Take note of which cylinder you pulled the plug from that has the discoloration if it returns. A compression check will rule out a cracked head. Link to comment Share on other sites More sharing options...
87.5ea82txt Posted May 1, 2011 Share Posted May 1, 2011 Or better yet..... a leak down test would give you a better indication of your cylender's status including valve leaks. Link to comment Share on other sites More sharing options...
naru Posted May 1, 2011 Share Posted May 1, 2011 Has you car taken a recent Mexican vacation? I`ve never seen it, but apparently lead fouling can be greenish. http://www.circletrack.com/enginetech/ctrp_0403_spark_plug_tuning/reading.html Link to comment Share on other sites More sharing options...
nipper Posted May 1, 2011 Share Posted May 1, 2011 wanted to change out the plugs, only to find that I had 2 Denso and 2 NGK's ..all 4 plugs are correct for the 1990 loyale..installed on each side 1 ngk and 1 denso and then drove 1 hr ...out of curiosity I pulled the plugs and the denso were grayish in color through out while the ngk's were more whiteish with a greenish colored ground strap..switched them around and drove another 1/2 hr..pulled the plugs once more..basically no change to the plugs except that the green color was a little darker ..spark plug charts make no mention of this greenish tint..any ideas..timing, or are the plugs to hot?? Hpw old are the spark plug wires Link to comment Share on other sites More sharing options...
Petersubaru Posted May 2, 2011 Author Share Posted May 2, 2011 Hpw old are the spark plug wires Plug wires are new and the spark plugs never used before.. Link to comment Share on other sites More sharing options...
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