Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!
As stated, the coolant temperature is reported back to the ECU so that more fuel can be added, as when the engine is cold, only the lightest parts of the fuel actually mix with the air and burn. This is why the car runs very smokey when cold.
The ECU is given a percentage to increase the number in the map by for every 10 degrees for the current speed and load site. For example 100% will increase a 20ms fuel pulse to 40ms (double).
Most ECUs also control the ignition timing. In cold conditions, a spark is required sooner as the mixture is not nearly as volatile as it is when the engine is warm.