Chrysler Front Wheel Drive Cars 4-CYL 1981-1995 Repair Information

Electric Fuel Pump

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REMOVAL & INSTALLATION



See Figures 1 and 2

Click image to see an enlarged view

Fig. Fig. 1: The electric fuel pump is mounted in the fuel tank



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Fig. Fig. 2: Use a brass or non-metallic punch and mallet to loosen (counterclockwise) the retaining lockring

An electric fuel pump is used with fuel injection systems in order to provide higher and more uniform fuel pressures. It is located in the fuel tank.

  1. Relieve the fuel system pressure, as described earlier in this section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the fuel tank, as described at the end of this section.
  6.  
  7. Using a hammer and a brass or non-metallic punch, tap the fuel pump lockring counterclockwise to release it.
  8.  
  9. Remove the fuel pump and old O-ring seal from the fuel tank. Discard the old seal.
  10.  

To install:
  1. Wipe the seal area of the tank clean and install a new O-ring seal.
  2.  
  3. Replace the filter (sock) on the end of the pump if it appears to be damaged.
  4.  
  5. Position the pump in the fuel tank and install the locking ring. Tighten the ring in the same manner in which it was loosened, however tap the ring clockwise to tighten it
  6.  


WARNING
Do not overtighten the lockring, as this can cause fuel leakage.

  1. Install the fuel tank, as described at the end of this section.
  2.  
  3. Connect the negative battery cable.
  4.  

TESTING



See Figures 3 and 4

To perform this test, you will need a pressure gauge capable of reading pressures above 55 psi (379 kPa). The gauge must have a connection that will fit the fuel rail service valve. The gauge must be the equivalent of Chrysler pressure gauge No. C-4799 and the connector fitting compatible with pressure test adapter 6539. You may also need a T and the fittings necessary to connect the gauge into the fuel supply line at the tank, as well as a 2 gallon container suitable for collecting fuel.

  1. Release the fuel system pressure as described in Routine Maintenance .
  2.  
  3. Remove fuel hose quick-connect fitting from the chassis fuel line.
  4.  
  5. Install the adapter between the fuel supply hose and chassis fuel line assembly.
  6.  
  7. Hold the gauge and have someone start the engine. Run the engine at idle speed in Neutral (manual transaxles) or Park (automatic transaxles).
  8.  


CAUTION
Exercise extreme caution while under the hood with the engine running. Keep clear of all moving belts, fans, exhaust manifolds, etc.

  1. Read the pressure. It should be 39 psi (265 kPa) for 1991-95 models or 14.5 psi (100 kPa) for 1984-90 and early 1991 Shadow and Sundance models. If it is not at the specified value, note the fuel pressure.
  2.  
  3. Stop the engine.
  4.  
  5. Once again depressurize the system, disconnect the gauge and replace the protective cover.
  6.  
  7. If the pressure was correct, the test is complete. If the pressure is below the range, proceed with the next step; if it is too high, skip to Step 12.
  8.  


WARNING
In the next step, note that fuel may drain from the lines as you disconnect them. Make sure all surrounding exhaust system parts are cool and that all sources of ignition are removed from the area. Collect fuel and dispose of it safely.

  1. Connect the gauge into the fuel supply line running between the tank and the filter which is located at the rear of the vehicle.
  2.  


WARNING
Make sure all connections are secure.

  1. Have an assistant start the engine, then read the pressure gauge.
    1. If the pressure has risen more than 5 psi (35 kPa), replace the fuel filter.
    2.  
    3. If the pressure is now within range, allow the engine to cool and remove all sources of ignition; depressurize the system; disconnect the gauge from the lines; replace the fuel filter; and restore all connections.

      Click image to see an enlarged view

      Fig. Fig. 3: Fuel pressure gauge and adapter



      Click image to see an enlarged view

      Fig. Fig. 4: Checking the fuel pump output pressure

    4.  

  2.  
  3. If the pressure is still too low, gently and gradually pinch the fuel return line closed as you watch the gauge.
    1. If the pressure increases, the fuel pressure regulator is at fault.
    2.  
    3. If there is no change, the problem is either clogging of the filter sock mounted on the pump or a defective pump itself.
    4.  

  4.  
  5. If the pressure is too high, follow this procedure:
    1. Shut OFF the engine and allow it to cool.
    2.  
    3. Depressurize the fuel system, then disconnect the fuel return hose at the chassis, near the fuel tank.
    4.  
    5. Connect a 3 ft. (91cm) length of hose to the open end of the line running along the chassis (from the engine). Position the open end of the line into a container suitable for collecting fuel.
    6.  
    7. Have a helper start the engine, then check the pressure again. If it is now correct, check the in-tank fuel return hose for kinking.
    8.  
    9. If the in-tank fuel return hose is okay, and the system still exhibits excessive pressure with the tank half full or more, the fuel pump reservoir check valve or aspirator jet may be obstructed and the assembly must be replaced.
    10.  

  6.  
  7. If the pressure is still too high, perform the following:
    1. Shut the engine OFF , and allow it to cool.
    2.  
    3. Depressurize the system once again and reconnect the fuel lines at the rear.
    4.  
    5. Disconnect the fuel return hose but this time at the pressure regulator. Collect all fuel that drains.
    6.  
    7. Run the open connection into a large metal container.
    8.  
    9. Reconnect the fuel gauge to the fuel rail.
    10.  
    11. Start the engine and repeat the test. If the fuel pressure is now correct, clean a clogged return line or replace pinched or kinked sections of the return line. If no such problems exist, replace the fuel pressure regulator.
    12.  

  8.  

 
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