Fuel Pump Relay: Testing and Inspection
EARLY MODEL YEARRelay Terminal Identification:
FUEL PUMP RELAY TERMINAL IDENTIFICATION
The following is a list of the terminal numbers, with circuit codes, and color codes, and their function:
Circuit No. Terminal No. Color Code Description
A05 30 RD Has battery input voltage supplied through fusible link.
A61 87 OR/BK Connected to terminal 30 in the energized position, supplies output voltage to fuel pump, EGR/EVAP solenoid, and fuel injectors.
K5 86 VT/WT Connected to the ignition relay (terminal 30), which provides input voltage to the relay.
A62 85 OR/GN Connected to the ECU, and grounded by the ECU when distributor signal is present.
N/A 87A N/A Not used in these applications.
FUEL PUMP RELAY TEST
NOTE: The following test procedures assume that the ignition system is functioning, and that a good spark is evident at the plugs. If this not the case test the ignition system before proceeding with this test.
NOTE: The Fuel Pump relay operation may be tested with the use of the DRB II scanner or equivalent.
If no scanner is available proceed with the following test.
1. Using a digital voltmeter connect the negative lead to ground and the positive lead to the terminal 30 wire of the fuel pump relay connector.
^ If battery voltage is present proceed to step 2.
^ If no voltage is present, check fusible links and supply voltage from the battery.
2. Move the voltmeter positive lead to terminal 87 (OR/BK wire) of the fuel pump relay connector. Turn the ignition key to the START position and crank the engine.
^ If no voltage is present at terminal 87 proceed to step 3.
^ If battery voltage is present during cranking, the fuel pump relay is functioning normally and no further testing of the fuel pump relay is necessary.
3. Move the voltmeter positive lead to terminal 86 (VIO/WHT wire) of the fuel pump relay connector. Turn the ignition key to the RUN position. Battery voltage from the ignition relay (terminal 30) should be present.
^ If voltage is present proceed to step 4.
^ If no voltage is present there is either a bad connection or an open wire between terminal 30 of the ignition relay and terminal 86 of the fuel pump relay. Locate and repair bad connector or open in wire, and test operation.
4. Move voltmeter positive lead to terminal 85 of the fuel pump relay connector. Turn ignition key to START position, and crank engine, while observing voltage. Voltage should be present and drop to less than 1 volt within 2 seconds during cranking.
^ If voltage does not drop, proceed to step 5.
^ If voltage drops, and there is voltage at terminal 30 and no voltage at terminal 87 the relay is bad. Replace the fuel pump relay and check operation.
^ If no voltage is present, disconnect the fuel pump relay, and connect an ohmmeter between terminal 86 terminal 85 of the fuel pump relay and check for continuity. If no continuity exists replace the fuel pump relay and test operation.
5. Disconnect the 35 way ECU, and 6 way diagnostic connectors and fuel pump relay. Connect an ohmmeter between terminal 85 of the fuel pump relay connector and the yellow wire at pin connector no. 3 of the ECU. Check for continuity.
^ If no continuity exists repair open in wire, reconnect ECU and fuel pump relay, and test operation.
^ If continuity exists, the problem is computer related.
LATE MODEL YEAR
Relay Terminal Identification:
FUEL PUMP RELAY TERMINAL IDENTIFICATION
The following is a list of the terminal numbers, with circuit codes, and color codes, and their function:
Circuit No. Terminal No. Color Code Description
A14 30 RED Has battery input voltage supplied through fusible link.
A141 87 DG/BLK Connected to terminal 30 in the energized position, supplies output voltage to fuel pump, and the oxygen sensor heater element.
A21 86 DB Connected to the ignition circuit, which provides input voltage to the relay.
K51 85 DB/YL Connected to the Single Board Engine Controller II (SBEC II), and grounded by the SBEC II when the ignition switch is in the START or RUN position and a distributor signal is present.
N/A 87A N/A Not used in these applications.
FUEL PUMP RELAY TEST
NOTE: The following test procedures assume that the ignition system is functioning, and that a good spark is evident at the plugs. If this not the case test the ignition system before proceeding with this test.
NOTE: The Fuel Pump relay operation may be tested with the use of the DRB II scanner or equivalent.
If no scanner is available proceed with the following test.
1. Using a digital voltmeter connect the negative lead to ground and the positive lead to the terminal 30 wire of the fuel pump relay connector.
^ If battery voltage is present proceed to step 2.
^ If no voltage is present, check fusible links and supply voltage from the battery.
2. Move the voltmeter positive lead to terminal 87 (OR/BK wire) of the fuel pump relay connector. Turn the ignition key to the START position and crank the engine.
^ If no voltage is present at terminal 87 proceed to step 3.
^ If battery voltage is present during cranking, the fuel pump relay is functioning normally and no further testing of the fuel pump relay is necessary.
3. Move the voltmeter positive lead to terminal 86 (VIO/WHT wire) of the fuel pump relay connector. Turn the ignition key to the RUN position. Battery voltage from the ignition circuit should be present.
^ If voltage is present proceed to step 4.
^ If no voltage is present there is either a bad connection or an open wire between the ignition circuit and terminal 86 of the fuel pump relay. Locate and repair bad connector or open in wire, and test operation.
4. Move voltmeter positive lead to terminal 85 of the fuel pump relay connector. Turn ignition key to START position, and crank engine, while observing voltage. Voltage should be present and drop to less than 1 volt within 2 seconds during cranking.
^ If voltage does not drop, proceed to step 5.
^ If voltage drops, and there is voltage at terminal 30 and no voltage at terminal 87 the relay is bad. Replace the fuel pump relay and check operation.
^ If no voltage is present, disconnect the fuel pump relay, and connect an ohmmeter between terminal 86 terminal 85 of the fuel pump relay and check for continuity. If no continuity exists replace the fuel pump relay and test operation.
5. Disconnect the 60 way Single Board Engine Controller (SBEC II) connector and the fuel pump relay. Connect an ohmmeter between terminal 85 of the fuel pump relay connector and the DB/YL wire at pin connector no. 51 of the SBEC. Check for continuity.
^ If no continuity exists repair open in wire, reconnect SBEC and fuel pump relay, and test operation.
^ If continuity exists, the problem is computer related.