1 wet spark plug??
 

My car has been having some strange issues recently,, starting sometimes on 1 rotor , but when you blipped throttle it would fire on both, has slight hesitation when driving. (put new battery , new starter, didnt seem like it was cranking enough when starting).
Today i pulled the spark plugs and found something i never seen before...

Front rotor both plugs clean and dry.

Rear rotor, bottom plug dry and perfect,, but the top plug (T2) is wet through , i couldnt tell if it was fuel or coolant. (i have no coolant issues, only have to top water once every 3/4 months just an egg cup full).
Im gonna put in new plugs now anyway just incase its a faulty plug, might put new plug leads on aswell,,
could this possibly be a coil failure.
I turned over engine with plugs out ,nice even whoosh of air front and back.?

Just after a little input.

how does the spark look off of that plug?

Im gonna check out sparks today,, just ordered a coolant pressure tester, ( the only thing i cant answer is why was only the top plug wet,, why not both plugs in one rotor??)

because its probably not firing, or fouled. doubt if coolant leak, does it make sense your leading be wet too? pull the main relay (green one), check how far spark jumps, then turn the plug and ground it so you can see the spark action.

Rear rotor, bottom plug dry and perfect,, but the top plug (T2) is wet through , i couldnt tell if it was fuel or coolant. (i have no coolant issues, only have to top water once every 3/4 months just an egg cup full).

I don't want to be crappy here but I think your coolant seals are on their way out. I speak from experience as I am in the final stages of a rebuild right now.

Having to top off the coolant with even a slight amount means your coolant is going somewhere. My guess is it's getting burned up in the engine. It will get progressively worse. I took mine to the mechanic and had a compression test done and it was great on both rotors. He has a Mazda compression tester. So I knew the apex seals were good. A pressure test was also done and it didn't show any leakdown, but we later found out that the seals were only leaking after the engine warmed up. Sneaky huh?

Anyway, long story short, only the rear rotor on my car was fouling the plugs with coolant. It would fire on one rotor and after getting going, the second rotor would kick in. I did the "champagne test" with a Lisle funnel and all the symptoms were there of leaking coolant seals. I also had some white smoke on start up. Not all of the time but only after the car sat for a day or two. This got worse adn so did the hard starts. Eventually, I knew it was the coolant seals that were going.

The rebuild showed that to be absolutely true. They were in bad shape.

The bad news is that I needed a rebuild and a new wiring harness :(. The good news is that I had it street ported while it was apart. Can't wait to get her back. Good luck with your issue.

Yes im leaning towards coolant seals (i licked spark plug yes i know disgusting,, but i know the taste of antifreeze and thats what it tasted like).
Only thing pissing me off is,, engine was rebuilt 2 years ago 5000 miles on motor, Brand new rotor housings, pineapple vitton coolant seals. First engine failed due to coolant seals (retaining wall broke away). Coolant pressure tester arriving tommorow will test that anyway.

or do the champagne test

Found split coolant pipe today (possible reason for coolant loss. fingers crossed).
Fired up 2 days in a row perfect with new spark plugs,, fingers crossed.

Tommorow is coolant pressure tester and champagne test.

Ok i did a coolant pressure test today,, i pumped it up to 15psi then waited 30 mins,, i got a 1psi drop (but not sure i had any drop actually as the cap that came with the kit kept leaking if the pump was moved even slightly). I cant find any external water leaks but the coolant line to the throttle must be leaking when it gets warm because i can see the pink coolant i have stained the pipe.
Another note is since ive changed the spark plugs car has been started 4 times, each time perfect start both rotors,, i have no clouds of white smoke on start up. (possible spark plug fault?)

Did the champagne test while engine was cold and got no bubbles at all.

Im gonna drive car for a few days and monitor coolant loss..

What is the champagne test??

champagne test - start engine cold run, for a few seconds, turn off, open coolant cap near engine block to check for bubbles. the bubbles are likely from compression leaking past the seals between rotor housing.

likewise there is the muddy oil observation (water of coolant mixing w/oil), and the white smoke out of exhaust from coolant leaking into the oil pan or being vaporized in the rotors and out the exhaust.

tiger 18, loss of coolant on motor side could be into the overflow tank due to either coolant cap not operating properly, or the overflow lines not being air tight. I added some clamps and zip ties at the connections.

how far could did you get your spark to jump on the rear trailing?