Fuel System Description: Notes

The fuel system is comprised of two subsystems. The fuel supply system and the fuel metering system. The correct amount of fuel can not be delivered to the engine cylinders without a constant supply of air from the air intake system. The air intake system provides measured clean air to each cylinder for proper mixture with the pressurized fuel. The powertrain control module (PCM), along with the information sensors and switches, controls the activity between all three systems.

Callout	Component Name
1	Fuel Rail
2	Quick Connect Fuel Line Fittings
3	Fill Limiter Vent Valve (FLVV)
4	EVAP Canister
5	Fuel Filler Door
6	Fuel Filler Pipe
7	Fuel Sender Assembly, includes fuel pump
8	Fuel and EVAP Lines
9	Fuel Tank
10	Fuel Injectors

Callout	Component Name
1	Fuel Rail
2	Quick Connect Fuel Line Fittings, in engine compartment
3	Fill Limiter Vent Valve (FLVV)
4	EVAP Canister
5	Fuel Filler Door
6	Fuel Filler Pipe
7	Fuel Sender Assembly, includes fuel pump
8	Quick Connect Fuel Line Fittings, fuel tank
9	Fuel and EVAP Lines
10	Fuel Tank
11	Fuel Injectors

The fuel supply system is a returnless on-demand design, that reduces evaporative emissions. The fuel metering system is a sequential fuel injection (SFI) design. The function of the fuel metering system is deliver the correct amount of fuel to the engine under all operating conditions. The main component of the vehicle's fuel metering system is the fuel injectors. There is one fuel injector for each cylinder. The fuel injectors are controlled sequentially by the PCM. The PCM bases the control of the fuel injectors on several important engine parameters. These engine parameters include the following:

• The mass air flow (MAF) sensor
• The intake air temperature (IAT) sensor
• The engine coolant temperature (ECT) sensor
• The throttle position (TP) sensor
• The engine speed (RPM)
• The heated oxygen sensor (HO2S)

The engine is designed to use only unleaded fuel. Unleaded fuel must be used for proper emission control system operation. Using unleaded fuel will also decrease spark plug fouling and extend engine oil life. Leaded fuel can damage the emission control system. The use of leaded fuel can result in the loss of emission warranty coverage. Refer to Fuel System Specifications .

The vehicle fuel system is equipped with an evaporative emission (EVAP) control system that minimizes the release of fuel vapors to the atmosphere. For more information on the EVAP system, refer to Evaporative Emission (EVAP) Control System Description .