Mitsubishi Eclipse 1990-1998 Repair Guide

Fuel Pump

Print

REMOVAL & INSTALLATION



1990-94 Vehicles
EXCEPT AWD MODELS

See Figures 1, 2, 3 and 4

  1. Properly relieve the fuel system pressure as outlined earlier in this section.
  2.  
  3. Raise and safely support the vehicle.
  4.  
  5. Drain the fuel from the fuel tank into an approved gasoline container.
  6.  
  7. Remove the electrical connectors at the fuel pump. Make sure there is enough slack in the electrical harness of the fuel gauge unit to allow for the fuel tank to be lowered slightly. If not, label and disconnect the electrical harness at the fuel gauge unit.
  8.  


CAUTION
Cover the high pressure fuel hose with rags to prevent splash of fuel caused by residual pressure in the fuel pipe line.

  1. Disconnect the high pressure fuel line connector at the pump.
  2.  
  3. Loosen self-locking nuts on tank support straps to the end of the stud bolts.
  4.  
  5. Remove the right side lateral rod attaching bolt and disconnect the arm from the right body coupling. Lower the lateral rod and suspend from the axle beam using wire.
  6.  
  7. Remove the holding bolt and gasket from the base of the tank.
  8.  
  9. Remove the fuel pump assembly.
  10.  



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the fuel pump, fuel gauge sending unit and related components

To install:
  1. Align the 3 projections on packing with the holes on the fuel pump and the nipples on the pump facing the same direction as before removal.
  2.  



Click image to see an enlarged view

Fig. Fig. 2: When installing the electric fuel pump, align the 3 position projections with the holes in the pump

  1. Install the holding bolt through the bottom of the tank. Make sure the gasket on the bolt is replaced and is not pinched during installation. Tighten to 10 ft. lbs. (14 Nm).
  2.  
  3. Install the right side lateral rod and attaching bolt into the right body coupling. Tighten loosely only, at this time.
  4.  



Click image to see an enlarged view

Fig. Fig. 3: During installation of the fuel gauge unit, align the 2 position projections with the holes in the fuel gauge unit.



Click image to see an enlarged view

Fig. Fig. 4: Tighten the self-locking nuts until the rear end of the tank band contacts the body of the vehicle

  1. Tighten self-locking nuts on tank support straps until tank is seated fully. Tighten nuts to 22 ft. lbs. (31 Nm).
  2.  
  3. Install the high pressure fuel hose connector and tighten to 29 ft. lbs. (40 Nm).
  4.  
  5. Install the electrical connectors onto the fuel pump and gauge unit assemblies.
  6.  
  7. Lower the vehicle so the suspension supports the weight of the vehicle. Tighten the lateral rod attaching bolt to 58-72 ft. lbs. (80-100 Nm).
  8.  
  9. Refill the fuel tank with fuel drained during this procedure.
  10.  
  11. Connect the negative battery cable and check the entire system for proper operation and leaks.
  12.  

awd MODELS

See Figures 5 and 6

  1. Properly relieve the fuel system pressure as outlined earlier in this section.
  2.  
  3. The fuel pump is located in the fuel tank. Remove the hole cover located in the rear floor pan.
  4.  
  5. Partially drain the fuel tank into an approved gasoline container.
  6.  
  7. Remove the electrical connector from the fuel pump.
  8.  
  9. Remove the overfill limiter (two-way valve), as required.
  10.  



Click image to see an enlarged view

Fig. Fig. 5: Exploded view of the fuel pump, gauge sending unit and related components

  1. Cover the hose connection with a shop towel to prevent any splash of fuel due to residual pressure in the fuel pipe. Remove the high pressure fuel hose connector.
  2.  
  3. Remove the fuel pump and gauge assembly from the tank. Note positioning of pump prior to removal from tank.
  4.  

To install:
  1. Align the 3 projections on the packing with the holes on the fuel pump and the nipples on the pump facing the same direction as before removal. Install the retainers and tighten to 2 ft. lbs. (3 Nm).
  2.  
  3. Install the high pressure hose connection and tighten to 29 ft. lbs. (40 Nm).
  4.  
  5. Install the overfill limiter (two-way valve) and the electrical connector to the fuel pump.
  6.  
  7. Fill the fuel tank with the gasoline removed during this procedure.
  8.  
  9. Reconnect the negative battery cable and check the entire system for leaks.
  10.  



Click image to see an enlarged view

Fig. Fig. 6: Before installing the hole cover, apply a suitable sealant to the rear floor pan

  1. Install MOPAR Rope Caulk Sealer part 4026044 or equivalent, to the rear floor pan and install the cover into place.
  2.  

1995-98 Vehicles

See Figures 7, 8, 9 and 10

On these vehicles, is possible to remove the fuel pump and/or gauge assembly by working through the access panel under the rear seat cushion instead of having to lower or remove the fuel tank.

  1. Properly relieve the fuel system pressure, as outlined earlier in this section, but keep the rear seat cushion off and the connector(s) detached.
  2.  
  3. If not already done, remove the protector.
  4.  
  5. Disconnect the fuel pump hoses and connectors, then remove the fuel pump from the vehicle.
  6.  



Click image to see an enlarged view

Fig. Fig. 7: The fuel pump is located under the rear seat cushion

To install:
  1. For FWD vehicles, place the fuel pump in the vehicle, aligning the packing positioning projections with the holes in the fuel pump.
  2.  



Click image to see an enlarged view

Fig. Fig. 8: When installing the fuel pump, make sure the projections are properly aligned with the holes in the pump assembly

  1. For AWD vehicles, perform the following:
    1. Check to be sure the fuel tank packing is not damaged. If it is, it must be replaced.
    2.  
    3. Place soapy water on the inside of the packing, then install the fuel pump assembly. Do NOT tilt the assembly during installation.
    4.  
    5. Apply soapy water to the outside thread of the fuel tank. Use special tool MB994180 or an equivalent spanner wrench to tighten the cap to the specified torque. Make sure that the marks on the fuel tank and pump assembly are aligned.
    6.  

  2.  
  3. For AWD vehicles, make sure the packing is installed properly, as shown in the accompanying figure.
  4.  



Click image to see an enlarged view

Fig. Fig. 9: On AWD vehicles, you need a spanner wrench to tighten the fuel pump assembly cap


WARNING
Make sure the pump assembly does not turn together with the cap when tightening the cap. If the mating marks are not aligned, the position of the flat will not be correct and the fuel gauge indicator light and gauge will not work properly.



Click image to see an enlarged view

Fig. Fig. 10: The fuel pump packing must be properly installed for sealing purposes

  1. For AWD vehicles, check for leaks as follows:
    1. Apply soapy water to the circumference of the cap.
    2.  
    3. Choke the vapor hose and main hose, apply and internal pressure of 1.5 psi (10 kPa) or less from the return hose and make sure no bubbles form in the soapy water.
    4.  

  2.  
  3. Install the protector and attach the fuel pump electrical connector.
  4.  
  5. Install the rear seat cushion.
  6.  
  7. Connect the negative battery cable.
  8.  

TESTING



Fuel Pump Operation Check

See Figures 11 and 12

  1. Set the ignition switch to the OFF position.
  2.  
  3. Check that when battery voltage is directly applied to the fuel pump check terminal located in the engine compartment, the operating sound of the fuel pump can be heard.
  4.  

Since the fuel pump is located in the fuel tank, its operating sound cannot be readily heard. Remove the fuel tank cap and listen to the operating sound through the filler port.



Click image to see an enlarged view

Fig. Fig. 11: Checking fuel pump operation with battery voltage applied to the fuel pump check terminal-1990-94 2.0L engine shown



Click image to see an enlarged view

Fig. Fig. 12: Location of the fuel pump drive connector-1995-98 2.0L turbo and 2.4L engines shown

  1. Hold the high pressure fuel hose between your fingers and check that the fuel pressure in the lines can be felt.
  2.  

Pressure Testing
EXCEPT 1995-98 2.0L NON-TURBO ENGINES

See Figures 13, 15, 16, 17 and 18

  1. Relieve the fuel system pressure as outlined earlier.
  2.  


CAUTION
Cover the hose connection with a shop towel to prevent the splash of fuel that can be caused by residual pressure in the fuel pipe line.

  1. Disconnect the high pressure fuel line from the fuel rail.
  2.  



Click image to see an enlarged view

Fig. Fig. 13: Location of the high pressure fuel hose and fuel rail-1990-94 vehicles



Click image to see an enlarged view

Fig. Fig. 14: High pressure fuel hose location-1995-98 2.0L turbo and 2.4L engine

  1. On 1990-94 2.0L engine, remove the throttle body stay.
  2.  



Click image to see an enlarged view

Fig. Fig. 15: If necessary, remove the throttle body stay

  1. Connect a fuel pressure gauge to tools MD998709 and MD998742 or exact equivalent, with appropriate adapters, seals and/or gaskets to prevent leaks during the test. Install the gauge and adapter between the delivery pipe and high pressure hose.
  2.  



Click image to see an enlarged view

Fig. Fig. 16: Exploded view of the fuel pressure gauge and adapter set



Click image to see an enlarged view

Fig. Fig. 17: Install of the fuel pressure gauge on the fuel rail-2.0L engine shown, others similar

  1. Connect the negative battery cable.
  2.  
  3. For 1990-94 vehicles, apply battery voltage to the terminal for fuel pump check terminal located in the engine compartment. Run the fuel pump and check for leaks at the pressure gauge connection.
  4.  
  5. For 1995-98 vehicles, connect the fuel pump drive terminal to the positive battery terminal using a jumper wire to drive the fuel pump. Check the fuel pressure gauge and tool connections for leaks. Disconnect the jumper wire from the fuel pump drive terminal to stop the fuel pump.
  6.  
  7. Start the engine and run at curb idle speed.
  8.  
  9. For 1995-98 vehicles, measure the fuel pressure. For 2.0L turbo engines, the pressure should be 33 psi (230 kPa). For 2.4L engines, the fuel pressure should be 38 psi (270 kPa).
  10.  
  11. Locate and disconnect the vacuum hose from the fuel pressure regulator. Plug the end of the hose. Measure the fuel pressure and compare with the following specifications:
  12.  



Click image to see an enlarged view

Fig. Fig. 18: Disconnect and plug the regulator vacuum hose, then measure the fuel pressure

    1. 1990-94 non turbo engines:47-50 psi (330-350 kPa).
    2.  
    3. 1990-94 turbo engines with manual transaxle:36-38 psi (250-270 kPa).
    4.  
    5. 1990-94 turbo engines with automatic transaxle: 41-46 psi (290-320 kPa).
    6.  
    7. 1995-98 2.0L turbo engines: 42-45 psi (289-309 kPa).
    8.  
    9. 2.4L engines: 47-50 psi (330-350 kPa).
    10.  


  1. For 1990-94 vehicles, reconnect the pressure regulator vacuum hose, then measure the fuel pressure (engine idling) and compare with the following specifications:
    1. 1990-94 non turbo engines:38 psi (270 kPa).
    2.  
    3. 1990-94 turbo engines with manual transaxle:27 psi (190 kPa).
    4.  
    5. 1990-94 turbo engines with automatic transaxle: 33 psi (230 kPa).
    6.  

  2.  
  3. After the fuel pressure stabilizes, race the engine 2-3 times and check that the fuel pressure does not fall when the engine is running at idle.
  4.  
  5. Check to be sure there is fuel pressure in the return hose by gently pressing the fuel return hose with fingers while racing the engine.
  6.  

There will be no fuel pressure in the return hose when the volume of fuel flow is low.

  1. If the results fall outside of specification, refer to the following:

    If fuel pressure is too low, check for a clogged fuel filter, a defective fuel pressure regulator or a defective fuel pump, any of which will require replacement.
     
    If fuel pressure is too high, the fuel pressure regulator is defective and will have to be replaced or the fuel return is bent or clogged.
     
    If the fuel pressure reading does not change when the vacuum hose is disconnected, the hose is clogged or the valve is stuck in the fuel pressure regulator and it will have to be replaced.
     

  2.  
  3. Stop the engine and check for changes in the fuel pressure gauge. It should not drop. If the gauge reading does drop, watch the rate of drop. If fuel pressure drops slowly, the likely cause is a leaking injector which will require replacement. If the fuel pressure drops immediately after the engine is stopped, the check valve in the fuel pump isn't closing and the fuel pump will have to be replaced.
  4.  
  5. Relieve fuel system pressure.
  6.  
  7. Disconnect the high pressure hose and remove the fuel pressure gauge from the delivery pipe.
  8.  
  9. Install a new O-ring in the groove of the high pressure hose. Connect the hose to the delivery pipe and tighten the screws. After installation, apply battery voltage to the terminal for fuel pump activation to run the fuel pump. Check for leaks.
  10.  
  11. Reinstall the throttle body stay, if removed.
  12.  

1995-98 2.0L NON-TURBO ENGINES

See Figure 19

Testing the fuel pressure on these vehicles requires the use of a scan tool.

  1. Properly relieve the fuel system pressure.
  2.  
  3. Remove the protective cover from the service valve on the fuel rail.
  4.  
  5. Connect Fuel Pressure Gauge MB995051 to the service valve.
  6.  



Click image to see an enlarged view

Fig. Fig. 19: Attach the fuel gauge to the service valve on the fuel rail

When using the scan tool fuel system test, the fuel pump relay stays energized for 7 minutes, until the test is stopped or until the ignition switch is turned of the OFF position.

  1. Turn the ignition key to the ON position. Use a suitable scan tool to access the "Fuel System Test". This test will activate the fuel pump and pressurize the system. The fuel pressure should be around 47-50 psi (330-350 kPa).
  2.  
  3. Use the scan tool to pressurize the fuel system, then make sure there is no fuel leakage from the service valve.
  4.  
  5. If the results fall outside of specification, refer to the following:

    If fuel pressure is too low, check for a clogged fuel filter, a defective fuel pressure regulator or a defective fuel pump, any of which will require replacement.
     
    If fuel pressure is too high, the fuel pressure regulator is defective and will have to be replaced or the fuel return is bent or clogged.
     

  6.  
  7. Using the scan tool, with the ignition key ON , repeat the fuel system test.
  8.  
  9. Turn the ignition switch OFF , then check the gauge reading. It's normal if the reading does not drop in about 2 minutes. If it does, check the rate of the drop and compare with the following:

    If the fuel pressure drops gradually, you have either a leaky injector or fuel regulator valve seat and the defective component should be replaced.
     
    If the fuel pressure drops sharply, check that the valve in the fuel pump is held open. If not, replace the fuel pump.
     

  10.  
  11. After testing has been completed, remove the fuel pressure gauge and install the protective cover onto the fuel rail service valve.
  12.  

 
label.common.footer.alt.autozoneLogo