Ohm reading on spark plugs

[Frankenchevy]

I no longer use resistance to verify electrical integrity. It's almost useless. The only time it's 100% accurate is when looking for a short.

It’s crazy that all of the ACDELCO plugs measured OL. I pulled my existing NGKs and they all measured within spec.

I still find a few automotive uses for measuring resistance. It’s good for testing ground path. Also, checking plug wires.

 

[Cuba]

It’s crazy that all of the ACDELCO plugs measured OL. I pulled my existing NGKs and they all measured within spec.

I still find a few automotive uses for measuring resistance. It’s good for testing ground path. Also, checking plug wires.

It's good for checking opens in plug wires... but when heat is involved, it can change resistance as well. Higher. I no longer trust "ohming" anything, unless I'm looking for a short to ground or something as you've stated. Loads or current & heat change everything.