Sealing the fuel pump flange to the fuel tank in a 1993 nissan pickup. Any tricks to getting the o-ring to seal properly?

REMOVAL & INSTALLATION


CAUTION
Fuel injection systems remain under pressure, even after the engine has been turned OFF. The fuel system pressure must be relieved before disconnecting any fuel lines. Failure to do so may result in fire and/or personal injury.

1. If equipped with air suspension, the air suspension switch, located on the right-hand side of the luggage compartment, must be turned to the OFF position before raising the vehicle.
2. Disconnect the negative battery cable.
3. Relieve fuel system pressure using the recommended procedure.
4. Raise and safely support the vehicle.
5. Remove the fuel tank from the vehicle and place on a suitable work bench.
6. Remove any dirt that has accumulated around the fuel pump retaining flange so it will not enter the tank during pump removal and installation.
7. On 1989-94 models, turn the fuel pump locking ring counterclockwise and remove the locking ring.
8. On 1995-98 models, remove 6 retaining bolts around the perimeter of the fuel pump module.
9. Remove the fuel pump/sending unit assembly. Remove and discard the seal ring.

To install:

1. Clean the fuel pump mounting flange, fuel tank mounting surface and seal ring groove.
2. Apply a light coating of grease on a new seal ring to hold it in place during assembly and install in the seal ring groove.
3. Install the fuel pump/sending unit assembly carefully to ensure the filter is not damaged. Make sure the locating keys are in the keyways and the seal ring remains in the groove.
4. Hold the pump assembly in place and install the locking ring finger-tight. Make sure all the locking tabs are under the tank lock ring tabs.
5. Rotate the locking ring clockwise until the ring is against the stops.
6. Install the fuel tank into the vehicle.
7. Lower the vehicle.
8. If equipped with air suspension, turn the air suspension switch to the ON position.
9. Add a minimum of 10 gallons of fuel to the tank and check for leaks.
10. Reconnect the negative battery cable.
11. Turn the ignition switch to the RUN position several times to pressurize the fuel system. Check for fuel leaks and correct as necessary.
12. Start the engine and check for leaks.
13. Road test the vehicle and check for proper operation.

REMOVAL & INSTALLATION


CAUTION
Fuel injection systems remain under pressure, even after the engine has been turned OFF. The fuel system pressure must be relieved before disconnecting any fuel lines. Failure to do so may result in fire and/or personal injury.

1. If equipped with air suspension, the air suspension switch, located on the right-hand side of the luggage compartment, must be turned to the OFF position before raising the vehicle.
2. Disconnect the negative battery cable.
3. Relieve fuel system pressure using the recommended procedure.
4. Raise and safely support the vehicle.
5. Remove the fuel tank from the vehicle and place on a suitable work bench.
6. Remove any dirt that has accumulated around the fuel pump retaining flange so it will not enter the tank during pump removal and installation.
7. On 1989-94 models, turn the fuel pump locking ring counterclockwise and remove the locking ring.
8. On 1995-98 models, remove 6 retaining bolts around the perimeter of the fuel pump module.
9. Remove the fuel pump/sending unit assembly. Remove and discard the seal ring.

To install:

1. Clean the fuel pump mounting flange, fuel tank mounting surface and seal ring groove.
2. Apply a light coating of grease on a new seal ring to hold it in place during assembly and install in the seal ring groove.
3. Install the fuel pump/sending unit assembly carefully to ensure the filter is not damaged. Make sure the locating keys are in the keyways and the seal ring remains in the groove.
4. Hold the pump assembly in place and install the locking ring finger-tight. Make sure all the locking tabs are under the tank lock ring tabs.
5. Rotate the locking ring clockwise until the ring is against the stops.
6. Install the fuel tank into the vehicle.
7. Lower the vehicle.
8. If equipped with air suspension, turn the air suspension switch to the ON position.
9. Add a minimum of 10 gallons of fuel to the tank and check for leaks.
10. Reconnect the negative battery cable.
11. Turn the ignition switch to the RUN position several times to pressurize the fuel system. Check for fuel leaks and correct as necessary.
12. Start the engine and check for leaks.
13. Road test the vehicle and check for proper operation.

Removal & Installation

1. Before servicing the vehicle, refer to the Precautions Section.
   
2. Relieve the fuel system pressure.
   
3. Disconnect the negative battery cable.
   
4. Remove or disconnect:
   
   • Cover under rear seat
     
   • Electrical connector
     
   • Fuel supply and return lines
     
5. Using spanner tool 3217, remove the fuel pump flange nut.
   
6. Remove the fuel pump unit and seal.
   
7. Installation is the reverse of removal. Be sure to use new sealing rings and/or gaskets. Tighten the fuel pump flange nut to 55 ft. lbs. (75 Nm) and make sure the markings on the flange nut match the marking on the fuel tank.
   

two possibilities are the throttle position sensor is bad/disconnected or the fuel pump is not hooked up properly i.e. the o-ring for the pump is not sealing at the tank. Check your fuel pressure at the rail on top of the engine with a gauge set you can borrow for free at Advance Auto, Pep Boys, Auto Zone or other commercial auto supply stores.

See Figure 1
Two different electric fuel pump configurations were used on fuel injected models. One consists of a low pressure in-tank boost pump in conjunction with an external, frame-mounted high pressure pump. The low pressure pump is used to provide pressurized fuel to the inlet of the high pressure pump and helps prevent noise and heating problems. System pressure is controlled by a pressure regulator mounted on the engine.
The other configuration consists of an in-tank high pressure pump which does not utilize a boost pump.

Fig. Fig. 1: Disassembled electric fuel pump

REMOVAL & INSTALLATION

In-Tank Pump
See Figures 2, 3 and 4

1. Disconnect the negative battery cable.
2. Depressurize the system and drain as much gas from the tank by pumping out through the filler neck.
3. Raise and support the rear end on jackstands.
4. Disconnect the fuel supply, return and vent lines at the right and left side of the frame.
5. Disconnect the wiring to the fuel pump.

Fig. Fig. 2: Low pressure in-tank electric fuel pump

Fig. Fig. 3: High pressure in-tank fuel pump

Fig. Fig. 4: Removal of electric fuel pump

1. Support the gas tank, loosen and remove the mounting straps. Remove the gas tank.
2. Disconnect the lines and harness at the pump flange.
3. Clean the outside of the mounting flange and retaining ring. Turn the fuel pump lock ring counterclockwise and remove.
4. Remove the fuel pump.

To install:

1. Clean the mounting surfaces. Put a light coat of grease on the mounting surfaces and on the new sealing ring. Install the new fuel pump.
2. Installation is in the reverse order of removal. Start the vehicle and check electric fuel pump operation. Check for fuel leaks.

High Pressure External Pump
See Figure 5

1. Disconnect the negative battery cable.
2. Depressurize the fuel system.
3. Raise and support the rear of the vehicle on jackstands.
4. Disconnect the inlet and outlet fuel lines.
5. Detach the electrical harness connection.
6. Bend down the retaining tab and remove the pump from the mounting bracket ring.
7. Install in reverse order. Make sure the pump is indexed correctly in the mounting bracket insulator. Start the vehicle and check electric fuel pump operation. Check for fuel leaks.

Fig. Fig. 5: High pressure external fuel pump

Relieve the fuel pressure at the pump switch located in the passenger compartment under the carpet of the transmission hump on the passenger side. Remove the fuel tank. Turn the lock ring counterclockwise until it's loose and remove the lock ring. Pull the fuel pump/sending unit from the tank being careful not to bend the arm for the sending unit float. Discard the old lock ring seal. Installation is reverse of removal with the following additions: (a)Apply a coat of heavy grease to the new lock ring seal to hold it in place during assembly. Install the seal in the lock ring groove. (b)Install the fuel sender/pump unit into the fuel tank so that the tabs of the unit are positioned into the slots in the fuel tank. Make sure to keep the seal in place during installation until the lock ring has been tightened properly. (c)Hold the fuel sender/pump unit in place, install and tighten the locking ring clockwise until the stop is against the retainer ring tab. - Mazda Pickups Repair Manual

hope this help

REMOVAL & INSTALLATION
CAUTION
Fuel injection systems remain under
pressure, even after the engine has been turned OFF. The fuel system pressure
must be relieved before disconnecting any fuel lines. Failure to do so may
result in fire and/or personal injury.

1. If equipped with air suspension, the air suspension switch, located on a
   side panel of the trunk compartment, must be turned to the OFF position
   before raising the vehicle.
   
2. Disconnect the negative battery cable.
   
3. Relieve fuel system pressure using the recommended procedure.
   
4. Raise and safely support the vehicle.
   
5. Remove the fuel tank from the vehicle and place on a suitable work bench.
   
6. Remove any dirt that has accumulated around the fuel pump retaining flange
   so it will not enter the tank during pump removal and installation.
   
7. On 1988-94 models, turn the fuel pump locking ring counterclockwise and
   remove the locking ring.
   
8. On 1995-00 models, remove the retaining bolts around the perimeter of the
   fuel pump module.
   
9. Remove the fuel pump/sending unit assembly. Remove and discard the seal
   ring.
   To install:
   
   
10. Clean the fuel pump mounting flange, fuel tank mounting surface and seal
    ring groove.
    
11. Apply a light coating of grease on a new seal ring to hold it in place
    during assembly and install it in the seal ring groove.
    
12. Install the fuel pump/sending unit assembly carefully to ensure the filter
    is not damaged. Make sure the locating keys are in the keyways and the seal ring
    remains in the groove.
    
13. Hold the pump assembly in place and install the locking ring finger-tight.
    Make sure all the locking tabs are under the tank lock ring tabs.
    
14. Rotate the locking ring clockwise until the ring is against the stops.
    
15. Install the fuel tank into the vehicle.
    
16. Lower the vehicle.
    
17. If equipped with air suspension, turn the air suspension switch to the
    ON position.
    
18. Add a minimum of 10 gallons of fuel to the tank and check for leaks.
    
19. Reconnect the negative battery cable.
    
20. Turn the ignition switch to the RUN position several times to
    pressurize the fuel system. Check for fuel leaks and correct as necessary.
    
21. Start the engine and check for leaks.
    
22. Road test the vehicle and check for proper operation.
    
    
    
    
    
    Fig. 1: The fuel pump is located in the fuel tank. On some
    models it can be viewed from the side as shown here
    
    
    
    
    
    
    
    Fig. 2: Electric fuel pump removal
    
    
    
    
    
    
    
    Fig. 3: Fuel pump locking ring installation
    
    

Electric Fuel Pump REMOVAL & INSTALLATION Non-Supercharged

1. Disconnect the negative battery cable and properly relieve the fuel system pressure.
2. Remove the fuel tank and place it on a bench.
3. Remove any dirt that has accumulated around the fuel pump retaining flange so it will not enter the tank during pump removal and installation.
4. Turn the fuel pump locking ring counterclockwise and remove the locking ring.
5. Remove the fuel pump and bracket assembly. Remove and discard the seal ring. To install:
   
6. Clean the fuel pump mounting flange, fuel tank mounting surface and seal ring groove.
7. Apply a light coating of grease on a new seal ring to hold it in place during assembly and install in the seal ring groove.
8. Install the fuel pump and bracket assembly carefully to ensure the filter is not damaged. Make sure the locating keys are in the keyways and the seal ring remains in the groove.
9. Hold the pump assembly in place and install the locking ring finger-tight. Make sure all the locking tabs are under the tank lock ring tabs.
10. Rotate the locking ring clockwise until the ring is against the stops.
11. Install the fuel tank in the vehicle. Add a minimum of 10 gallons of fuel to the tank and check for leaks.
12. Install a suitable fuel pressure gauge on the valve on the fuel rail.
13. Turn the ignition switch from OFF to ON for 3 seconds. Repeat this procedure 5–10 times until the pressure gauge shows at least 35 psi. Check for fuel leaks.
14. Remove the pressure gauge, start the engine and check for leaks.

Put switch in off-Disconnect the negative battery-Remove luggage floor covering comparment-Disconnect harness connector supply line and return line from flange-Remove screw cap with ring spanner-Remove flange nut and sealing ring from opening-Looseng fuel tank fuel pump

Removal & Installation See fuel pump under fuel tank in this section.

CAUTION Fuel injection systems remain under pressure, even after the engine has been turned OFF. The fuel system pressure must be relieved before disconnecting any fuel lines. Failure to do so may result in fire and/or personal injury.

1. If equipped with air suspension, the air suspension switch, located on a side panel of the trunk compartment, must be turned to the OFF position before raising the vehicle.
   
2. Disconnect the negative battery cable.
   
3. Relieve fuel system pressure using the recommended procedure.
   
4. Raise and safely support the vehicle.
   
5. Remove the fuel tank from the vehicle and place on a suitable work bench.
   
6. Remove any dirt that has accumulated around the fuel pump retaining flange so it will not enter the tank during pump removal and installation.
   
7. On 1988–94 models, turn the fuel pump locking ring counterclockwise and remove the locking ring.
   
8. On 1995–00 models, remove the retaining bolts around the perimeter of the fuel pump module.
   
9. Remove the fuel pump/sending unit assembly. Remove and discard the seal ring.
   

To install:

1. Clean the fuel pump mounting flange, fuel tank mounting surface and seal ring groove.
   
2. Apply a light coating of grease on a new seal ring to hold it in place during assembly and install it in the seal ring groove.
   
3. Install the fuel pump/sending unit assembly carefully to ensure the filter is not damaged. Make sure the locating keys are in the keyways and the seal ring remains in the groove.
   
4. Hold the pump assembly in place and install the locking ring finger-tight. Make sure all the locking tabs are under the tank lock ring tabs.
   
5. Rotate the locking ring clockwise until the ring is against the stops.
   
6. Install the fuel tank into the vehicle.
   
7. Lower the vehicle.
   
8. If equipped with air suspension, turn the air suspension switch to the ON position.
   
9. Add a minimum of 10 gallons of fuel to the tank and check for leaks.
   
10. Reconnect the negative battery cable.
    
11. Turn the ignition switch to the RUN position several times to pressurize the fuel system. Check for fuel leaks and correct as necessary.
    
12. Start the engine and check for leaks.
    
13. Road test the vehicle and check for proper operation.
    

The fuel pump is located in the fuel tank. On some models it can be viewed from the side as shown here


Electric fuel pump removal


Fuel pump locking ring installation