Coolant Temperature Sensor/Switch (For Computer): Description and Operation

Engine Coolant Temperature:

Coolant Temperature Correction

Whenever the engine coolant temperature is below 5°C (41°F) and manifold pressure is below 1.0 bar, the ignition timing will be advanced from the basic curve. This gives the air/fuel mixture more time to burn at low engine temperatures.

Example:
At 3000 RPM and a manifold pressure of 0.8 bar the basic ignition curve calls for a timing angle of 28° BTDC. If the coolant temperature is -15°C (5°F) the ignition timing would be advanced 7° to 35° BTDC.