Conditions that control timing advance or retard on electronic engines?

[JStieger]

On our 24-valve engines the ECM dynamically controls the injection timing advance or retard. My question is, how?



What boost, engine temperature, rpm etc levels dictate if the timing should be advanced or retarded?



For example when my engine is cold, the rail pressure looks to be lower than when the engine is fully warmed up. To me this would suggest that the timing is retarded when the engine is cold (to make it easier to start??? lower cylinder pressure stresses when cold???).



Under high boost would the ECM want to retard the timing also?



Appreciate any insite from folks a lot smarter than I!

 

[ThrottleJockey]

Timing is ADVANCED when the engine is cold to aid in starting (water temp under 160*F), lightly loaded at cruising (boost to wheel speed ratio) and a couple other conditions I can't think of.



Engine timing will RETARD a heavily loaded, high boost/fuel condition like towing up a mountain. Hot starts will cause it to bump back a bit, etc... .