I will try and answer your question basically it boils down to 3 sources,
(1) Base knowledge: Taking your example of the engine control going into open loop at wide open throttle or on foot off the throttle deceleration, basically all engines with O2 sensors go open loop when the throttle is floored and on deceleration cut the fuel injectors off until the RPM slows to near idle speed.
(2) Systems Description & Operation: Car manufacturers have always published "System Description & Operation" manuals that are either a section of the manufacturers official Repair Manual or more likely a separate electronic publication. These manual a subsystem for example the cooling fan and list all the inputs and outputs of the system and how it functions. For example it will describe the inputs required to fire the coils and fuel injectors, show the crankshaft and camshaft tooth patterns and what the computer's fall back strategy is if one of these signals is missing. For example on the car I drive the manual states a crank sensor failure results in a cranking no start but a cam sensor failure will allow the engine to start but cause longer cranking time and the injectors to revert to bank firing. Companies like Snap-On and ALLDATA pay the car manufacturers for the right to allow their users access to this type of information through their products.
(3) Observe it and work out what happening: A good example is the video made on a Honda ignition misfire which triggered the intentional shutdown of one injector to protect the catalysts.
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
I have explored repair manuals and practical tests (even i have installed complete EFI systems from one car brand to another, just for a deeper understanding).
Related to those "separate electronic publications" you mentioned,
What's the exact name?
Where can i get it?
Do you know about any website/database?
