Файл: 92FWD_14.pdf

side the pump assembly in the fuel return circuit, prevents fuel tank leakage if the line is damaged during an accident. The third valve, in the pump outlet, maintains pump pressure during engine off conditions. The fuel pump relay provides voltage to the fuel pump.

All front wheel drive car fuel systems, except Turbo III vehicles, use the same fuel pump. The pump has a maximum unregulated pressure output of approximately 930 kPa (135 psi). Fuel Pressure is regulated at the fuel rail or throttle body by a fuel pressure regulator. Refer to the Fuel System Pressure Chart for pressure specifications.

Release fuel system pressure before servicing the fuel tank, fuel pump, fuel lines, fuel filter, or parts of the fuel rail. Follow the Fuel System Pressure Release procedure to relieve fuel system pressure.

Fig. 3 Fuel Pump

FUEL SYSTEM PRESSURE

FUEL PUMP PRESSURE TESTÐALL EXCEPT 2.2L/2.5L TBI AND 3.0L MPI

The specifications in the Fuel Pressure chart reflect system pressure with the vacuum hose removed from the pressure regulator.

(1)Remove the vacuum hose from the pressure regulator before checking fuel pressure.

(2)Release fuel system pressure. Refer to the Fuel System Pressure Release procedure in this group.

(3) Connect Fuel Pressure Gauge C-4799 to service port on fuel rail (Fig. 4).

Fig. 4 Fuel Pressure TestingÐEngines With Service

Ports

CAUTION: When using the ASD Fuel System Test, the Auto Shutdown (ASD) Relay remains energized for either 7 minutes, until the test is stopped, or until the ignition switch is turned to the Off position.

(4) Place the ignition key in the ON position. Using the DRB II tester, access ASD Fuel System Test. The ASD Fuel System Test will activate the fuel pump and pressurize the system.

If the gauge reads the specification listed in the Fuel System Pressure chart, further testing is not required. If pressure is not correct, record the pressure and remove gauge. Use the DRB II ASD Fuel System Test to pressurize the system. Ensure fuel does not leak from the fuel rail service valve. Install protective cover on fuel rail service valve.

If pressure is below specifications, proceed to Fuel System Pressure Below Specifications . If pressure is above specifications, proceed to Fuel System Pressure Above Specifications.

Fuel System Pressure Below Specifications

If the fuel pressure reading in step (4) was below specifications, test the system according to the following procedure.

WARNING: RELEASE FUEL SYSTEM PRESSURE BEFORE DISCONNECTING A FUEL SYSTEM HOSE OR COMPONENT.

(a)Perform Fuel Pressure Release procedure.

(b)Install Fuel Pressure Gauge C-4799 and Fuel Pressure Test Adapter 6539 in the fuel supply line between the fuel tank and fuel filter at the rear of vehicle (Fig. 5).

(c)Using the DRB II, with the ignition key in the ON position, repeat the ASD Fuel System Test.

14 - 6 FUEL SYSTEMS

Fig. 5 Fuel Pressure Test

²If pressure is at least 5 psi higher than reading recorded in step (4), replace fuel filter.

²If no change is observed, gently squeeze the return hose. If fuel pressure increases, replace pressure regulator. If gauge reading does not change while squeezing the return hose, the problem is either a plugged inlet strainer or defective fuel pump.

Fuel System Pressure Above Specifications

If the fuel pressure reading in step (4) was above specifications, test the system according to the following procedure.

WARNING: RELEASE FUEL SYSTEM PRESSURE BEFORE DISCONNECTING A FUEL SYSTEM HOSE OR COMPONENT.

(a)Perform Fuel Pressure Release procedure.

(b)Remove the fuel return line hose from the fuel pump at fuel tank.

(c)Connect Fuel Pressure Test Adapter 6541 to the return line (Fig. 6). Place the other end of adapter 6541 into an approved gasoline container (minimum 2 gallon size). All return fuel will flow into container.

(d)Using the DRB II, with the ignition key in the ON position, repeat the ASD Fuel System Test.

²If pressure is now correct, replace fuel pump assembly.

²If pressure is still above specifications, remove fuel return hose from chassis fuel tubes (at engine). Attach Fuel Pressure Test Connect Adapter 6541 to the fuel return hose and place other end of hose in clean container (Fig. 7). Repeat test. If pressure is now correct, check for restricted fuel return line. If no change is observed, replace fuel pressure regulator.

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Fig. 6 Fuel Pressure Return Test

Fig. 7 Fuel Return Connection

FUEL PUMP PRESSURE TESTÐ2.2L/2.5L TBI and

3.0L MPI ENGINES

WARNING: RELEASE FUEL SYSTEM PRESSURE BEFORE DISCONNECTING A FUEL SYSTEM HOSE OR COMPONENT.

The specifications in the Fuel Pressure chart reflect system pressure with the vacuum hose removed from the pressure regulator. Remove the vacuum line from the pressure regulator on 3.0L engines before testing fuel system pressure. The pressure regulators on 2.2L/2.5L TBI engines are not vacuum assisted.

(1)Perform fuel system pressure release.

(2)Remove fuel supply hose quick connector from the chassis lines (at the engine).

(3)Connect Fuel Pressure Gauge C-4799 to Fuel Pressure Test Adapter 6539 (Fig. 8). Install the adapter between fuel supply hose and chassis fuel line assembly.

Fig. 8 Fuel Pressure Gauge and Adapter

CAUTION: When using the ASD Fuel System Test, the Auto Shutdown (ASD) Relay remains energized for either 7 minutes, until the test is stopped, or until the ignition switch is turned to the Off position.

(4) Place the ignition key in the ON position. Using the DRB II tester, access ASD Fuel System Test. The ASD Fuel System Test will activate the fuel pump and pressurize the system.

If the gauge reads the pressure shown in the Fuel System Pressure chart, further testing is not required. If pressure is not correct, record the pressure and remove gauge.

If pressure is below specifications, proceed to Fuel System Pressure Below Specifications. If pressure is above specifications, proceed to Fuel System Pressure Above Specifications.

Fuel System Pressure Below Specifications

If the fuel pressure reading in step (4) was below specifications, test the system according to the following procedure.

WARNING: RELEASE FUEL SYSTEM PRESSURE BEFORE DISCONNECTING A FUEL SYSTEM HOSE OR COMPONENT.

(a)Perform Fuel Pressure Release procedure.

(b)Install Fuel Pressure Gauge C-4799 and Fuel Pressure Adapter 6433 in the fuel supply line (Fig.

5)between the fuel tank and fuel filter.

(c)Using the DRB II, with the ignition key in the

ON position, repeat the ASD Fuel System Test.

²If pressure is at least 5 psi higher than reading recorded in step (4), replace fuel filter.

²If no change is observed, gently the squeeze return hose. If fuel pressure increases, replace pressure regulator. If the gauge reading does not change while squeezing the return hose, the problem is either a plugged inlet strainer or defective fuel pump.

Fuel System Pressure Above Specifications

If the fuel pressure reading in step (4) was above specifications test the system according to the following procedure.

WARNING: FUEL SYSTEM PRESSURE MUST BE RELEASED BEFORE A FUEL SYSTEM HOSE OR COMPONENT IS DISCONNECTED.

(a)Perform Fuel Pressure Release procedure.

(b)Install Fuel Pressure Gauge C-4799 and Fuel Pressure Adapter 6433 in the fuel supply line between the fuel tank and fuel filter (Fig. 5).

(c)Remove the fuel return line hose from the fuel pump at fuel tank. Connect Fuel Pressure Test Adapter 6541 to the return line (Fig. 6). Place the other end of adapter 6541 into an approved gasoline container (minimum 2 gallon size). All return fuel will flow into container.

(d)Using the DRB II, with the ignition key in the ON position, repeat the ASD Fuel System Test.

²If pressure is now correct, replace fuel pump assembly.

²If pressure is still above specifications, remove fuel return hose from chassis fuel tubes (at engine). Attach Fuel Pressure Test Connect Adapter 6541 to the fuel return hose and place other end of hose in clean approved gasoline container (Fig. 7). Repeat test. If pressure is now correct, check for restricted fuel return line. If no change is observed, replace fuel pressure regulator.

MECHANICAL MALFUNCTIONS

Mechanical malfunctions are more difficult to diagnose with this system. The engine controller compensates for some mechanical malfunctions. If engine performance problems are encountered, and no fault codes are displayed, the problem may be mechanical rather than electronic.

FUEL PUMP REMOVAL

Remove the fuel tank to service the fuel pump. Refer to Fuel Tank Section for fuel tank removal.

(1)Using a hammer and a brass drift punch carefully tap lock ring counter clockwise to release pump (Fig. 9).

(2)Remove fuel pump and O-ring seal from tank. Discard old seal.

FUEL PUMP STRAINER SERVICE

REMOVAL

(1)Bend locking tabs on fuel pump reservoir assembly to clear locking tangs on the fuel pump strainer (Fig. 10).

(2)Pull strainer off.

(3)Remove strainer O-ring from the fuel pump reservoir body.

(4)Remove any contaminants by washing the inside of the fuel tank.

Fig. 9 Fuel Pump Service

Fig. 10 Fuel Strainer Service

INSTALLATION

(1)Lubricate the strainer O-ring with Mopar Silicone Spray Lube.

(2)Insert strainer O-ring into outlet of strainer so that it sits evenly on the step inside the outlet.

(3)Push strainer onto the inlet of the fuel pump reservoir body. Make sure the locking tabs on the reservoir body lock over the locking tangs on the strainer.

FUEL PUMP INSTALLATION

(1)Wipe seal area of tank clean and place a new O-ring seal in position on pump.

(2)Position fuel pump in tank with locking ring.

(3)Using a hammer and brass drift punch drive ring around clockwise to lock pump in place.

(4) Install tank. Refer to the Fuel Tank Section in this Group.

FUEL FILTERÐALL VEHICLES

REMOVAL

WARNING: FUEL SYSTEM PRESSURE MUST BE RELEASED BEFORE THE FUEL FILTER IS REMOVED.

(1)Perform the Fuel System Pressure Release procedure.

(2)) Remove the fuel filter retaining screw (Fig. 11). Remove fuel filter from mounting plate.

(3)Wrap a shop towel around hoses to absorb fuel. Remove quick-connect fittings at filter and fuel supply tube. Refer to Quick-Connect Fittings in this section.

Fig. 11 Fuel Filter

INSTALLATION

(1)Connect quick-connect fuel fittings to the filter and fuel supply line. Refer to Quick-Connect Fittings in this section.

(2)Position filter assembly on mounting plate and tighten mounting screw to 8 NIm (75 in. lbs.) torque.

CAUTION: When using the ASD Fuel System Test, the Auto Shutdown (ASD) Relay remains energized for either 7 minutes, until the test is stopped, or until the ignition switch is turned to the Off position.

(3) Place the ignition key in the ON position. Using the DRB II tester, access ASD Fuel System Test. The ASD Fuel System Test will activate the fuel pump and pressurize the system. Inspect for leaks.

CHASSIS FUEL TUBES

CAUTION: Over tightening the pump lock ring may result in a leak.

figure 12 shows fuel system component locations and chassis fuel tube routings.