Section 91 (Engine Controls - Theory & Operation - Bi-Fuel): Introduction

WARNING: This page is about a different car, the 2002 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Compressed natural gas may also be referred to as natural gas. Liquefied petroleum gas may also be referred to as propane. Natural gas is lighter than air, propane is heavier than air.

This article covers basic description and operation of bi-fuel engine performance-related systems and components. Bi-fuel refers to the F150 Pickup 5.4L that can operate using gasoline or alternative fuel. Alternative fuel may be either Compressed Natural Gas (CNG) or Liquefied Petroleum Gas (LPG). Bi-fuel vehicles are either gasoline/CNG, or gasoline/LPG. Bi-fuel systems are separate and have unique components. Alternative fuels are not compatible and should not be mixed or substituted. For illustrations of bi-fuel system components, see Fig 1 and Fig 2 . Read entire article before diagnosing vehicles or systems with which you are not completely familiar.

Switching vehicle operation between gasoline and either CNG or LPG is performed using ALT/GAS fuel switch inside vehicle before ignition is turned on. If vehicle runs out of alternative fuel, system will automatically switch to gasoline operation.

Fig 1: Identifying Bi-Fuel Compressed Natural Gas System Components

Courtesy of FORD MOTOR CO.

Fig 2: Identifying Bi-Fuel Liquefied Petroleum Gas System Components

Courtesy of FORD MOTOR CO.