hey guys i am new here and i just bought me a 2012 mazda 2 maxx 5 speed.

i just replaced the spark plugs and the old plugs has this dark sandy gunk on them. anyone know if this is a sign of engine problems?

no check engine light comes up.


all 4 spark plugs looked the same

 

Normal. Nothing to be worried about.

 

From the single picture and only one view angle it looks fairly normal for a high mileage plug and idle burn prior you pulling the spark .

 

thats the only pic had for the spark plug. but thanks for the replys guys

 

1. Normal wear from a high mileage spark plug.
2. The small white area is an indication of good ignition and also ECU correctly adjusting AFRs' (Air Fuel Ration)
3. This is an indication that some crankcase oil has gotten into the intake charge likely from the PCV system. Not much you can do about this but it does indicate that you may have some carbon build up in the combustion chamber and valves.

There is a few more things but those are really all we need to think about on a daily driver


Now if you want a really good evaluation of a spark plug? This can only be done with a power pull which is a little harder to perform. It requires running the engine up to speed then shutting the engine off and not allowing the throttle to idle and then pull a plug and examine it completely. This means the still used "OLD SCHOOL" like 99% of the spark plug charts on the internet that really dates back to the 50's but to use a flash light and magnifying glass to see all the way down the electrode. LOL Don't worry mostly only Track guys do that. LOL
You can also use an oscilloscope to help determine the ignition system health which includes the spark plug as well to determine the optimal spark plug gap for your personal engine. Here again unless you are into obtaining the optimal ignition of fuel just do what most do ....swap out the plugs for the expensive ones you just paste some anti-seize on the thread and spin'um down. I do at least recomend to torque them the what the Factory Service Manual recommends comparing to the spark plug manufacture and hope they don't conflict each other? LOL Ya that happens more then you would think. I tend to desire myself based on what the thread material is, cast iron head,Aluminum head, aluminum head with steel thread incerts, etc. I really hate repairing spark plug thread from some "bloke" that really should be even changing spark plugs! LOL