Fuel Delivery and Air Induction: Description and Operation

FUEL DELIVERY SYSTEM
The fuel delivery system consists of: the electric fuel pump, fuel filter, fuel pressure regulator, fuel tubes/lines/hoses, fuel rail, fuel injectors, fuel tank, accelerator pedal and throttle cable.

The intank fuel pump module contains the fuel pump, fuel filter, level sensor, and fuel pressure regulator. The pump, fuel filter, and regulator are serviced as part of the fuel pump module. Refer to Fuel Pump Module.

A fuel return system is used on all models. Fuel is returned through the fuel pressure regulator within the fuel pump module.

The fuel tank assembly consists of: the fuel tank, filler tube, fuel gauge sending unit/electric fuel pump module, rollover valve, ORVR control valve, fuel fill check valve, and a pressure-vacuum filler cap.

Also to be considered part of the fuel system is the evaporation control system. This is designed to reduce the emission of fuel vapors into the atmosphere. The description and function of the Evaporative Control System is found in the Emission Control Systems.

LONG-TERM STORAGE
When storing your Dodge Viper for long periods, leave the fuel tank and fuel system full of fuel. For further information about long-term vehicle storage, refer to the Lubrication and Maintenance.

FUEL FILTER
The fuel filter mounts inside the fuel pump module and is a non-serviceable part.

FUEL LEVEL SENSOR
The level sensor is attached to the side of the fuel pump module. The level sensor consists of a float, an arm, and a variable resistor.

As the fuel level increases, the float and arm move up. This decreases the sending unit resistance, causing the fuel gauge on the instrument panel to read full. The fuel level sensor (fuel gauge sending unit) sends a signal to the PCM to indicate fuel level. The purpose of this feature is to prevent a false setting of misfire and fuel system monitor trouble codes if the fuel level is less than approximately 15 percent of its rated capacity.

FUEL TUBES/LINES/HOSES AND CLAMPS
Also refer to Quick-Connect Fittings.

WARNING: THE FUEL SYSTEM IS UNDER A CONSTANT PRESSURE (EVEN WITH THE ENGINE OFF).BEFORE SERVICING ANY FUEL SYSTEM HOSES, FITTINGS OR LINES, THE FUEL SYSTEM PRESSURE MUST BE RELEASED. REFER TO THE FUEL SYSTEM PRESSURE RELEASE PROCEDURE.

The lines/tubes/hoses used on fuel injected vehicles are of a special construction. This is due to the higher fuel pressures and the possibility of contaminated fuel in this system. If it is necessary to replace these lines/tubes/hoses, only those marked EFM/EFI may be used.

If equipped: The hose clamps used to secure rubber hoses on fuel injected vehicles are of a special rolled edge construction. This construction is used to prevent the edge of the clamp from cutting into the hose. Only these rolled edge type clamps may be used in this system. All other types of clamps may cut into the hoses and cause high-pressure fuel leaks.

Use new original equipment type hose clamps.

FUEL PRESSURE REGULATOR
A fuel pressure regulator is used on all gas powered engines. It is located inside the fuel pump module. It contains a diaphragm, calibrated springs and a fuel return valve.

The pressure regulator is a mechanical device that is calibrated to maintain fuel system operating pressure of approximately 379 kPa (55 psi) at the fuel injectors.

It contains a diaphragm, calibrated springs and a fuel return valve.

Fuel is supplied to the regulator by the electric fuel pump through an opening tube at the bottom of regulator.

The fuel pump module contains a check valve to maintain some fuel pressure when the engine is not operating. This will help to start the engine.

If fuel pressure at the pressure regulator exceeds approximately 56 psi, an internal diaphragm closes and excess fuel pressure is routed back into the tank through the pressure regulator. A separate fuel return line is not used with any gas powered engine.

The pressure regulator is a mechanical device that is NOT controlled by the PCM or engine vacuum.

ELECTRIC FUEL PUMP
The electric fuel pump is located in and is part of the fuel pump module. It is a positive displacement, gerotor type, immersible pump with a permanent magnet electric motor. The fuel pump module is suspended in fuel in the fuel tank.

The pump draws fuel through a strainer and pushes it through the motor to the outlet. The pump contains a check valve. The valve, in the pump outlet, maintains pump pressure during engine OFF conditions. The fuel pump relay provides voltage to the fuel pump. The fuel pump has a maximum dead-headed pressure output of approximately 880 kPa (130 psi). The regulator adjusts fuel system pressure to approximately 379 kPa (55 psi).

Fuel Pump Electrical Control
Voltage to operate the electric pump is supplied through the fuel pump relay. For an electrical operational description of the fuel pump refer to fuel Pump Relay-PCM Output.

FUEL PUMP MODULE
The fuel pump module contains the fuel pump, fuel reservoir, level sensor, inlet strainer, fuel pressure regulator, and fuel filter. The level sensor is the only serviceable items. If the fuel pump, fuel pressure regulator, or fuel filter requires service, replace the fuel pump module.

FUEL RAIL/INTAKE MANIFOLD
The fuel system operates at approximately 379 kPa (55 psi).

The intake manifold contains the fuel passage for the injectors. Check fuel system pressure at the test port at the rear of the intake manifold on the passenger side.

Fig.11 Fuel Tank And Control Valve:

FUEL TANK
The fuel tank is equipped with fuel and vapor controls that allow the vehicle to pass a full 3600 rollover without fuel leakage.

The fuel filler cap also acts as a pressure/vacuum valve. When air pressure inside the fuel tank gets too high or too low, the fuel cap valve opens to relieve the difference in pressure.

An evaporation control system restricts fuel evaporation into the atmosphere and reduces unburned hydrocarbons. Vapors from the fuel tank are collected in a charcoal filled canister. The vapors are held in the canister until the engine is operating. When the engine is running, the vapors are drawn through the intake manifold into the combustion chambers.

The ORVR control valve manages the flow of vapor during refueling. It also controls maximum fuel volume of the fuel tank (Fig. 11).

FUEL PUMP INLET STRAINER
The fuel pump inlet strainer is a non-serviceable part.

ROLLOVER VALVE
All vehicles have rollover valve(s) on top of the fuel tank.

The valves prevent fuel flow through the fuel tank vent valve hoses should the vehicle rollover.

The rollover valves on the fuel tank are not serviceable.

PRESSURE VACUUM FILLER CAP
The fuel fill cap is threaded/quarter turn onto the end of the fuel filler tube. It's purpose is to retain vapors and fuel in the fuel tank.

The fuel filler cap incorporates a two-way relief valve that is closed to atmosphere during normal operating conditions. The relief valve is calibrated to open when a pressure of 10.9 to 13.5 kPa (1.6 to 2.0 psi) or vacuum of 1.0 to 2.0 kPa (0.15 to 0.29 psi) occurs in the fuel tank. When the pressure or vacuum is relieved, the valve returns to the normally closed position. The cap must be replaced by a similar unit if replacement is necessary.

CAUTION: Remove the fuel filler cap to release fuel tank pressure before disconnecting any fuel system component.