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Lately my 1.8 civic has been running really rough. I put in new plugs and after a few hours with it still running rough I took them back out and much to my surprise the #2, and #3are dark colored but number #1, #4 are nice and white - like I believe they should be.
The odd part is that all are getting good spark.
I check timing on each plug and it appears they all reveal the timing is correct.
Thoughts?
Charlie
Notice #1, adn #4, seem to be nice and clean but #2, and #3 are dark, almost may be oily.
Thanks for the link. There were no NGK plugs within 50 miles so I bought what was in town just to get some testing done. I have not tested the injectors but I sure can..
Looking at the pic again, and it's hard to say on my end, but the gap looks a bit wide. What is it set at? What engine is this?
This is a 2014 R18 in a civic.
I am using an SDSEFI for spark and injection.
If I remember correctly the 1 and 4 spark together and the 2 and 3 spark together (waste spark) so the coincidence that the 2 and 3 spark plug tips look the same and the 1 and 4 look the same makes me think there is something going on with the ECU and or wiring. But all 4 plugs spark.
ADDED: They are gapped to .039...
Last edited by charosenz; May 6, 2018 at 07:25 PM.
Reason: added spark gap....
Folks, I may be a bit embarassed but I just found out it was failed compression. I had focused on the spark because it coincided with one side of the spark channel of the ECU vs the other channel, but at this point that seems to just have been a coincidence. Ill need to do a tear down to see why the compresssion failed in just #2 and #3....
I appreciate the help, and I post this in an effort that it may help someone else who stumble across this thread in the future and is faced with the same questions.
do a leakdown test before teardown and find out where the compression is leaking to. could be valve damage, could be valve lash out of adjustment, could be blown hg, or many other things
Spark Plug different color, meaning???
