Spark Plugs Worn Out?

[jayjr1105]

Originally Posted by supton
Originally Posted by Gebo
From what I see, assuming these are the correct plugs, I'd stay with OEM plugs and change out at 50K. If you are uncertain about which plug is OEM, I'd verify at the Mazda dealership and Mazda forum what the OEM plugs are. It appears the OEM was iridium. NOTE, it appears. IF, you used the wrong style plug, that may be why they look so worn out in only 65K miles. IDK?

I agree, it might be worthwhile to inspect after 25k or so. Those look really worn to me, which puts extra load on the coils. It might be worth just changing more often, if it's not big money, maybe just do it every 30k?

Very important about extra wear on the coils. However it's been determined that the OP may not be using the correct Iridium part. he's aware and will likely run the current ones 30K and then go OEM.

 

[Astro_Guy]

I'd be curious to know what the gap was in the old plugs. Obviously it's a good bit larger than the new ones. If nothing else, your pictures prove to me that spark plug gap is less critical than I had always believed, not withstanding arguments concerning wear on the coil packs.

 

[D1dad]

Good to know as I have nissans as well and am done paying $20 for laser irridiums. My wife's 18 rogue has densos from the factory so it looks like Nissan is using both or has switched to denso.



Originally Posted by bbhero
I have the Denso Iridium TT plugs in my car for the past 50k miles and the car runs perfect. . Way, way cheaper than the Denso long life iridium plugs that were selling for $16.49 a plug...

 

[NissanMaxima]

Does anyone have an answer for the OP's question about the tops of his pistons being black with carbon? I was curious as I observed the same thing when I changed out the OEM plugs on my Maxima with about 75k miles. I've watched some Chris Fix videos in the past where he has inserted a borescope down spark plug holes following various different types of fuel system cleaners and he saw minimal improvement in piston appearance.