THERMO Time Switch & Hot Start Pulse Relay

Thermo time switch provides ground for cold start valve. It is affected by engine temperature and starter current. Depending on engine coolant temperature, switch will take from 3-10 seconds to open. Injection through cold start valve will stop when thermo time switch opens.

Some models use hot start pulse relay to improve hot starting. While starter is being operated on cold engine, pulse relay allows cold start valve to spray small amounts of fuel at regular intervals after thermo time switch opens. On hot engines, pulse relay allows cold start valve to spray fuel after 2 seconds of starter operation. It then shuts off and sprays periodically until engine starts.