I'm with Wayne.
That is the simplest of the circuits. If you can trace it, there is nothing stopping you later from understanding anything in the EFI system!
What makes you think it's not working, stumbling, hesitation when cold?
Sensors used in the cold-start affect normal operation parameters so putting a patch may only delay the symptoms of a systemic breakdown of the system later (like during the summer, when you WANT to drive it!)