Cold Start Valve

The cold start valve is used to provide additional fuel during the crank mode to improve cold start-ups. This circuit is important when engine coolant temperature is low because the other injectors are not pulsed on long enough to provide the needed amount of fuel to start the engine.

The circuit is activated only in the crank mode. The power is supplied directly from the starter solenoid and is protected by a fuse. The system is controlled by a thermal time switch which provides a ground path for the valve during cranking when engine coolant temperature is below 95°F (35°C).

The thermal switch is made of a bi-metallic material which opens at a specified coolant temperature. This bi-metallic material is also heated by the winding in the thermal switch, allowing the valve to stay on for 8 seconds at 68°F (20°C) coolant temperature.

The time the thermal switch will stay closed varies inversely with coolant temperature. As the coolant temperature goes up, the cold start valve "on" time goes down.