Chart A-9 Cold Start Valve Test

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

The thermal switch is made of a bimetal material which opens at a specified coolant temperature. This bimetal is also heated by the winding in the thermal switch which allows the valve to stay "ON" for 8 seconds at 68°F(20°C) coolant. The time the thermal switch will stay closed varies inversely with coolant temperature. In other words, as the coolant temperature goes up, the cold start valve "ON" time goes down.

CHART TEST DESCRIPTION
1. Disconnecting the distributor 4-way connector will disable the other injectors. The amount of pressure drop depends on the temperature of the engine.

2. This test will determine the continuity through the thermal time switch to ground.