Spark Plugs

Issues Related to Spark Plugs

Condition	Comment
Larger gap spark plug	It can cause misfire - the car initial acceleration may delay because one or more of the spark plug didn't fire properly
Narrow gap spark plug	It may cause incomplete burn due to smaller spark (incomplete burn) - allow unburn oxygen to pass and detected by the oxygen sensor resulting in lean reading. As the ECU read lean it will command more fuel injection resulting in poor economy
Smaller tips spark plug	The smaller tips spark plug may consume more fuels as the spark is faster
Ignition Coil	The smaller the resistance of the ignition coil should go to the longest wiring likewise higher resistance should be connected to the shorter ignition cable to balance them out. This is shown at the end of the video: Spark Plug testing
Spark Plug Type	Personally based on this experiment the normal NGK spark plug VS NGK G-Power spark plug. DCPR7EA-9 vs DCPR7EGP. I would say the normal spark plug has better ignition spark compare to the G-Power. The picture below should explain why the smaller tip electrode spark plug has a drawback. Despite of it's consistency generating spark on the center but it lefts residual under negative electrode unburn fuel. So it would be better to have larger surface area positive electrode where the spark would jump randomly to prevent the unburn fuel. See picture below NGK G-Power DCPR7EGP.
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