Engine diagnostic plug

[Tyler]

Just curious if there are any modern devices that can read from these plugs, and what they would tell me if there were. There are at least two ports on a stock d-jet motor covered with little orange caps - one near the battery and another on the enging near the dizzy.

 

[velocewest]

The one near the dizzy will let you use a remote starter switch, and tell you when the engine passes TDC. No diagnostics.