Below are instructions for testing the Fuel Pump operation on 1988-1990 Buick Reatta.

The instructions below do not apply to 1991 models. The 1991 model fuel pump wiring is not the same as earlier models. Consult the 1991 Reatta service manual for more information.

You should connect a Fuel Pressure Tester (if you have one) to the fuel rail to check for proper fuel pressure. With a good pump and pressure regulator the pressure at the fuel rail should be about 40-42 psi.

These instructions are for step by step troubleshooting the Fuel Pump.  However, you might save yourself some time by simply replacing the Fuel Pump Relay first. If that corrects the problem the instructions below will not be needed.

TEST 1Does the Fuel Pump run when 12 volts is applied to the Fuel Pump Prime Connector?

fuel_pump_prime_connector.jpg
  • If the answer is NO: The problem is with the Fuel Pump or wiring going to it. There is no need to continue with further testing until the pump runs with 12 volts applied to the Fuel Pump Test Connector.
     
  • If the answer is YES: Go to TEST 2. >>

TEST 2:  Does Does the Fuel Pump Relay connector, terminal #1, have 12 volts when the key is turned to RUN?

fuel_pump_circuit.jpg
  • If the answer is NO: Check the 15 amp fuse #8 and replace if needed.
     
  • If the answer is YES: Test Fuel Pump Relay connector, terminal #2, for a good ground. Repair if needed. Go to TEST 3. >>

TEST 3:  Does the Fuel Pump Relay connector, terminal #5, have 12 volts when the key is turned to RUN?

Must be tested within a few seconds of turning the key to the run position.

  • If the answer is NO: Inspect the wiring between relay and ECM - test/replace ECM if the wiring is good.
     
  • If the answer is YES: Replace the Fuel Pump Relay.

    Thanks to members of the AACA Reatta forum for this information.

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