Cold Start Valve & THERMO-Time Switch

Unplug cold start valve and unscrew valve from throttle valve housing. Leave fuel line connected. Connect jumper wires to cold start valve and attach to battery or headlight connections for power source.
On 1975-77 models, disconnect airflow sensor connector. This isolates the safety circuit and allows fuel pump to run with ignition ON and engine not running.
On 1978-79 Volvo, connect Test Relay (5170) to ignition coil. See Figure. On 1978-79 Saab, use jumper wires between fuel pump relay circuit. This will permit fuel pump to operate with ignition ON, but engine off.
On all models, place cold start valve over a container. With ignition switch ON and voltage available to valve, fuel should spray for a short period (30 second maximum). Check for conical spray pattern.
If engine temperature is below 113°F (45°C), spray will be present when operating properly. If none occurs, check voltage at cold start valve. With starter energized, connect test lamp in series across valve contacts. Voltage indicates defective cold start valve.

Fig 1: Cold Start Valve Test
Courtesy of NOT AVAILABLE
On 1978-79 models, connect test lamp (with starter energized) to Blue/Yellow wire of cold start valve and ground. Voltage indicates defective thermo-time switch or defective wire between switch and cold start injector. If voltage is not present, check for defective wire between starter motor and cold start injector.
If engine temperature is above 113°F (45°C), and fuel injection occurs when starter is energized, either the switch or injector is defective. Remove connector from cold start injector. If there is injection when starter is energized, cold start injector is defective. If not, switch is defective.