Early Fuel Evaporation (EFE) Heater

Description:

Early Fuel Evaporation (EFE) Heater Operation
The early fuel evaporation (EFE) system provides rapid heating of the air/fuel mixture during cold start conditions. Rapid heating of the air/fuel mixture provides quick fuel evaporation and more uniform fuel distribution. Rapid heating of the air/fuel mixture improves cold driveability. The EFE system also reduces the length of time the engine is in open loop. Reducing the open loop operation time helps lower exhaust emission levels. The EFE system consists of the following components:
^ The EFE Heater (Positive Temperature Coefficient heater)
^ The EFE Heater Relay
The EFE heater is located between the throttle body fuel injection unit and the intake manifold. The EFE heater relay is mounted in the relay box.


The powertrain control module (PCM) will energize the EFE heater relay coil when the engine is below normal operating temperature and engine speed is above idle. Ignition positive voltage is supplied to the EFE heater through the electrical contacts in the EFE heater relay. The EFE heater will preheat the air/fuel mixture before it enters the combustion chambers. The PCM will de-energize the EFE system when the engine reaches normal operating temperature, or the engine speed is reduced to idle.