Proper way to check spark

[ponkotsu]

Thought I would share my mistake so other hacks like myself can learn. Trying to check the spark quality on my 4.6L Aviator. I used a regular spark plug and observed the spark. It was orange, not white or blue. I started chasing down potential electrical issues. Then I got online and read somewhere that the color of the spark on an HEI is meaningless. So I bought a HEI spark tester for $12 at Advance Auto. Rechecked, and all 8 cylinders have big beautiful spark. The gap and insulator on the tester are such that it assures you that you have enough voltage or it won't make any spark at all. Takes the guesswork out of the color. Bad news is I'm still looking for the root cause of my rough idle...

This was a super easy check. Took total of about 15 minutes to pull the covers and check all 8 cylinders with my wife turning the key for me.

This is what I used:

And you'll need to use a jumper cable directly to the battery ground also to be sure you get proper spark.

 

[BrooklynBay]

This tool is good for comparing the spark energy from each coil:

 

[ponkotsu]

I thought about buying the adjustable tool but thought it would be a little overkill. Probably on a high performance engine it's more important to have all cylinders as matched as possible. I think the tool I bought is similar to the Ford recommended tool.