Thermo time switch

Jaguar: XJ6 4.2 Series II USA, Canada and Japan models from engine no. 8L67735 (May 1978) and european models from engine no. 8L79250 (January 1979) plus all 4.2 Series III models • XJ12 Series II fuel injection models from engine no. 7P25001 (May 1975) plus all Series III models (1979-92) • XJS 5.3 V12 to VIN...188104 (1975-93)

Range Rover: Classic 3.5 V8 Efi, 3.9 V8 Efi and 4.2 V8 LSE models from VIN...CA167942 (1985-96)

to keep the cold start valve from injecting too much fuel and flooding the engine

Quelle: http://type2.com/bartnik/thermo.htm
The thermo-time switch consists of a contact to ground for the cold start valve and a bimetallic strip surrounded by a heater winding. When the engine is cold and the key is turned to "start," the bimetallic strip contacts the ground contact and allows the cold start injector to inject fuel. When the key is turned to "on," that powers the heating element inside the thermo-time switch. As the heater warms the bimetallic strip, it eventually bends away and stops grounding the cold start valve.

This all happens in 10 seconds or less. This is to keep the cold start valve from injecting too much fuel and flooding the engine. So if the engine doesn't start within the 10 seconds, the thermo-time switch will shut off the cold start valve to keep the engine from flooding for future starting attempts. When the engine is already hot, the contact in the thermo-time switch is open, preventing the cold start valve from operating. A stuck closed thermo-time switch could allow the cold start valve to operate too long during starting, causing engine flooding (but regardless, the cold start valve will still only operate when the starter is operating). If the thermo-time switch sticks open, it could keep the cold start valve from operating and cause hard cold starting