Fuel System

WARNING: DO NOT SMOKE, CARRY LIGHTED TOBACCO OR OPEN FLAME OF ANY TYPE WHEN WORKING ON OR NEAR ANY FUEL-RELATED COMPONENT. HIGHLY FLAMMABLE MIXTURES ARE ALWAYS PRESENT AND MAY BE IGNITED, RESULTING IN POSSIBLE PERSONAL INJURY.

An on-board vehicle Powertrain Control Module (PCM):
- accepts inputs from various electronic engine sensors to compute the required fuel flow rate necessary to maintain a prescribed air/fuel ratio throughout the operational range.
- outputs a command to the fuel injectors to meter the appropriate quantity of fuel.
- determines and compensates for the age of the vehicle and its uniqueness.
- automatically senses and compensates for changes in altitude (for example, from sea level to mountains).
- permits push starting the vehicle if it becomes necessary (manual transmission only).

All engines use a closed-type Positive Crankcase Ventilation (PCV) system and an exhaust emission system to control engine emissions within government specifications.

To maintain the required exhaust emission levels, the fuel delivery system must be:
- kept in good operating condition.
- adjusted to specifications.

Additional engine performance checks are required to keep the exhaust emissions at the specified minimum pollutant level. Refer to Maintenance Schedule for these performance checks and recommended intervals.

The "unleaded fuel only" nomenclature appears on the instrument cluster.

The fuel delivery subsystem consists of the following:
- high-pressure, in-tank mounted, electric fuel pump
- fuel filter/reservoir delivering fuel from the fuel tank
- 20-micron fuel filter
- fuel supply and return tubes
- fuel injection supply manifold which incorporates electrically-actuated fuel injectors directly above each of the engine's intake ports
- fuel injectors which, when energized, spray a metered quantity of fuel into the intake air system

A constant fuel pressure drop is maintained across the fuel injectors by a fuel pressure regulator.

The fuel pressure regulator is:
- connected in series with the fuel injector.
- positioned downstream from fuel injectors.

Excess fuel supplied by the fuel pump, but not required by the engine, passes through the fuel pressure regulator and returns to the fuel tank through a fuel return line.