Early Fuel Evaporation System: Description

Two Early Fuel Evaporation (EFE) systems are used on General Motors vehicles. The EFE systems are used to provide heat to the engine induction system during cold driveaway. Engines may be equipped with either the vacuum servo type or the electrical heater type EFE system.

Both the vacuum servo type and the electrical heater type systems provide rapid heating, resulting in faster fuel evaporation and more uniform fuel distribution. This also helps to reduce choke "on" time by warming the engine faster. This helps in reducing exhaust emission levels.