Advance Basic Control On The PCM selected basic angle of ignition advance from its memory based on engine speed, load, position of the kite of the throat and the engine coolant temperature. Relevant signals: a) air mass flow and / or intake manifold pressure (MAF sensor, or MAP VAF) b) Engine speed (Crankshaft Position Sensor – Crankshaft Position Sensor) c) Position of the Body Throat Acceleration (Sensor TPS) d) Engine Coolant Temperature (Sensor Coolant) (In some vehicles, Ford is the temperature of the cylinder head and / or head) Corrective Control Power Forward Progress Corrective Control Power makes the final adjustment current while on. The following correction factors are not in all vehicles. Correction Stage Motor Home Heating Power tempo is advanced to improve the manageability when coolant temperature is low. In some engine models, this correction changes the lead angle in accordance with the mass air flow (intake manifold pressure) and may be advanced about 15 degrees in extremely cold climates. Correction for High Temperatures To avoid detonation, jingles and overheating, ignition timing is retarded when the coolant temperature is too high. The ignition timing may be delayed about 5 due to this correction. Correction For Stable When Idling engine speed during idle fluctuated away from the target speed, the PCM adjusts ignition timing to stabilize the engine speed.
The PCM is constantly calculating the average speed of the motor. If engine speed falls below the target speed, the PCM time passes on to a predetermined angle. If the engine speed rises above the target speed, the PCM retards ignition timing to a predetermined angle.