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Discussion Starter #1
I just recently swapped my D15B7 to a JDM D16A and put new plugs in and it seems like 2 of the plugs are white on the ceramic part and the other 2 are brown. What does this mean? It seems to run ok and compression is around 175psi on all cylinders. I have around 600kms on the plugs in the picture below.

 

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Because the two on the left are so clean my guess would be they are being washed clean by fuel. Which means sometimes they are not firing. I am no expert but the two on the right look OK and normal to me.

From my own experience, I had a leaking headgasket which caused a tiny amount of coolant to enter the combustion chamber. The leak was so small it wasn't really apparent when driving the car. Eventually the car would have lots of trouble starting and when I pulled the plugs the two that weren't firing were wet with fuel and also squeaky clean like your two plugs on the left.

If the plugs on the left have any tiny brown rust flecks on them that would indicate water in the combustion chamber. Although it might take longer than 600km for rust to start happening.

If you have trouble starting it might be the same problem as I had. In any case, the two on the left look like the problem ones.
 

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Discussion Starter #7
injectors are stock, would a leakdown test tell me if i have even a small leak in my head gasket? And starting the car is not a problem it runs ok but seems to have a very slight sake to the idle even after a valve adjustment, IACV swap, fuel injector cleaner and full tuneup of ignition and fuel filter, and vacuum is steady at 20psi. I might have to drive it a bit longer cuz when i first got he car running it wasn't running good for a week so this could of been the issue.
 
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