Thermo Time Switch: Description and Operation

Cold Start Injector Time Switch Circuit Schematic:

The Cold Start Injector Time Switch, located on the engine, enables operation of the Cold Start Injector. When the engine is cold, (below 60° F), and the starter is activated, the time switch will ground allowing the Cold Start Injector to spray fuel into the intake plenum.

Ground is interrupted in two ways. The first is by engine coolant temperature heating the switch to above its calibrated thermal point. This prevents the Cold Start Injector from injecting fuel on warm engine restarts. The second interuption is by the internal time switch heater. When the starter is cranking, this heater will heat and break the circuit in approximately ten seconds or less to prevent engine flooding, if the engine does not start immediately.