Chart A-9, Cold Start Injector

Cold start injector provides additional fuel during cranking mode to improve engine starting during cold temperatures. Voltage is received from starter solenoid to cold start switch. Cold start switch also may be referred to as cold start injector timer. Cold start test switch provides a ground path for cold start injector during cranking when coolant temperature is less than 95°F (35°C). Amount of time cold start switch will be on depends on coolant temperature. Cold start test switch is located in coolant passage on front side of engine. Cold start test switch contains a 2-wire connector with Black or Black/White and Green wires.

1. Release fuel pressure before installing fuel pressure gauge. See BASIC TESTING article in the ENGINE PERFORMANCE Section. Disconnecting distributor connectors will disable the other fuel injectors. Amount of decrease in fuel pressure depends on engine temperature.
2. This determines continuity through cold start test switch to ground.

Fig 1: Chart A-9 Flow Chart, Cold Start Injector

Courtesy of GENERAL MOTORS CORP.

Fig 2: Chart A-9 Schematic, Cold Start Injector

Courtesy of GENERAL MOTORS CORP.