Saturn Coupes/Sedans/Wagons 1991-1998 Repair Guide

Fuel Pump

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REMOVAL & INSTALLATION



Fuel pump replacement or service requires the removal of the fuel tank. Refer to the Fuel Tank procedure later in this section for the proper pump replacement techniques.

TESTING



Fuel Pump Pressure Test

A Trouble Code 44 or 45 could indicate pressure regulator or system pressure problems. The pump pressure test may be used to determine if the fuel pump is delivering fuel at the proper pressure or if the pump must be replaced.


CAUTION
The following procedure will produce a small fuel spill and fumes. Make sure there is proper ventilation and be sure to take the appropriate fire safety precautions.

  1. Locate the pressure test port on the fuel supply line, below and behind the EGR valve. Properly relieve any residual system pressure, then remove the fuel gauge from the test port and install the port cap.
  2.  
  3. Disconnect the fuel supply hose from the metal line, then connect the fuel gauge to the supply hose using a suitable adapter. Make sure the gauge is capable of reading 0-100 psi (0-690 kPa).
  4.  
  5. Verify that the fuel gauge shut-off valve is closed, then turn the ignition switch ON without starting the engine to run the fuel pump and build pressure in the system. The pump will only run for about 2 seconds without the engine running. Bleed the air out of the gauge line and cycle the fuel pump again as required to fully bleed the gauge and establish an accurate pressure reading.
  6.  
  7. Once maximum pressure has been achieved, allow the reading to stabilize for 30 seconds. Normal pump pressure is 58-94 psi (400-650 kPa). Allow the gauge to sit undisturbed for five minutes after the pump stops running; pressure should leak down no more than 6-8 psi (41-55 kPa) from the maximum stabilized reading. This is a fuel pump pressure test only and the results will differ from the system pressure test.
  8.  
  9. Bleed off the fuel system pressure and repeat the test a minimum of 2 additional times to be certain of accurate results.
  10.  
  11. Install the bleed hose into an approved container, then bleed the fuel system pressure and remove the gauge from the line. Lubricate the male end of the fitting with clean engine oil and reconnect the fuel line.
  12.  

System Pressure Test

See Figure 1


CAUTION
The following procedure will produce a small fuel spill and fumes. Make sure there is proper ventilation and be sure to take the appropriate fire safety precautions.

  1. Remove the air cleaner or air intake tube assembly for access, then connect fuel pressure gauge SA9127E or an equivalent gauge capable of 0-100 psi (0-690 kPa) to the fuel system test port.
  2.  
  3. Close the fuel gauge shut-off valve. Turn the ignition switch ON to run the fuel pump and build pressure in the system, then turn the ignition OFF again. The pump will only run for about 2 seconds without the engine running. Bleed the air out of the gauge line and cycle the fuel pump again as required to fully bleed the gauge.
  4.  
  5. Cycle the ignition and check the gauge; pressure should be 38-44 psi (262-306 kPa) for 1991-97 models and 40-55 psi (276-379 kPa) on 1998 models. Allow the gauge to stabilize; after about 5 minutes with the pump not running, pressure should leak down no more than 6-8 psi (41-55 kPa).
  6.  
  7. Start and run the engine to normal operating temperature, then check the gauge for proper operating pressure. With the engine running at idle, pressure should be 31-36 psi (214-248 kPa).
  8.  
  9. On 1991-97 models, check the pressure regulator with the engine running at idle by disconnecting the vacuum line. With the line disconnected, the pressure should vary about 6-10 psi (40-70 kPa). If the pressure reading does not change and vacuum can be felt at the line' inlet, replace the regulator.
  10.  
  11. If pressure readings are low, perform the following:
    1. Check for bent or pinched lines.
    2.  
    3. Replace the fuel filter.
    4.  
    5. Check for proper fuel pump pressure.
    6.  
    7. Check the fuel pump for flow.
    8.  
    9. Substitute a known good fuel pressure regulator.
    10.  

  12.  
  13. If pressure readings are high, perform the following:
    1. Inspect for a restricted fuel return line.
    2.  
    3. Substitute a known good fuel pressure regulator.
    4.  

  14.  



Click image to see an enlarged view

Fig. Fig. 1: For 1991-97 models, disconnect the vacuum supply from the fuel pressure regulator-if the regulator is good, fuel pressure will vary

Pump Electrical Test

See Figures 2, 3, 4, 5 and 6

  1. On the Instrument Panel Junction Block (IPJB), located inside the vehicle beneath the center of the instrument panel, check the condition of the 10 amp fuel pump fuse. The inside of the access panel will provide the location of the fuel pump fuse and relay.
  2.  
  3. Locate and remove the fuel pump relay. On 1991-94 models, it is located to the top left of the relays in the IPJB. On 1995 and later models, it is located at the bottom right of the IPJB. To test the relay, another relay from the same block may be substituted, as they are identical. Using a voltmeter or test light, check for power to the fuel pump relay. With the ignition switch ON or OFF , there should be 12 volts between terminal 30 and ground.
  4.  
  5. Connect a voltmeter or test light to terminal 85 and a suitable ground. When the ignition switch is first turned ON , there will be voltage for about 2 seconds. This is power for the relay coil from the PCM. If there is no voltage, the PCM may be faulty.
  6.  
  7. Locate the fuel pump wiring harness connector in the trunk. When terminals 87 and 30 are jumpered together in the relay socket, there should be 12 volts at terminal A on the connector. The other terminals are for the fuel gauge. The pump ground wire connects from the pump to chassis ground.
  8.  



Click image to see an enlarged view

Fig. Fig. 2: Remove the access panel from the base of the dashboard center console in order to examine the fuel pump fuse and relay



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Fig. Fig. 3: The fuel pump relay is located in the Instrument Panel Junction Block (IPJB)



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Fig. Fig. 4: The fuel pump relay is at the top left of the relays located in the IPJB-1991-94 Saturn vehicles



Click image to see an enlarged view

Fig. Fig. 5: Schematic of the fuel pump power supply-all Saturn vehicles



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Fig. Fig. 6: The fuel pump relay is to the bottom right of the Instrument Panel Junction Block (IPJB)-1995 -98 Saturn vehicles

 
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