EFE Relay: Description and Operation

Cold Mixture Heater System:

The Cold Mixture Heater is an early fuel evaporative (EFE) system consisting of a Positive Temperature Coefficient (PTC) heater installed between the carburetor and intake manifold. The purpose of this EFE system is ensure atomization of fuel under cold start conditions (to improve exhaust emissions). When the engine coolant temperature is below 60°C (140°F), the ECU energizes the Cold Mixture Heater Relay. The closed relay supplies voltage to the cold mixture heater. The cool air-fuel mixture is heated and atomized by the heater before it reaches the combustion chamber for improved combustion.