Fuel Pump: Testing and Inspection

NOTE: Obtain code number and deactivate audio anti-theft system before disconnecting battery. Refer to ADJUSTMENT PROCEDURES.

WARNING: Before disconnecting any fuel line, release fuel pressure with the following procedure. When replacing fuel system components, keep sparks, cigarettes and open flames away from fuel. Use a rag as protection from spray when disconnecting hoses. Plug hoses while they are disconnected.

RELIEVING FUEL SYSTEM PRESSURE

Relieving Fuel System Pressure:

1. Start engine.
2. Disconnect fuel pump relay (circuit opening relay) connector.
3. After engine stalls, turn ignition "OFF."
4. Reconnect fuel pump relay connector.

PUMP OPERATION CHECK

Fuel System Priming:

1. Connect a jumper wire across diagnosis connector terminals "F/P" and "GND."
2. Remove fuel filler cap and turn ignition switch "ON."
3. Listen at fuel filler pipe for steady "hum" indicating the pump is running.

Fuel Pump Operation Check:

4. If no sound was heard, measure voltage at fuel pump connector. It should read approximately 12V.
5. If not correct, check fuel pump (circuit opening) relay, connectors, and wiring between relay and pump. Refer to FUEL PUMP RELAY (CIRCUIT OPENING RELAY) in this section. Also check that fuel pump ground wire is in good condition and properly connected.
6. If no problem has yet been detected, remove pump from tank. Refer to COMPONENT REPLACEMENT AND REPAIR PROCEDURES.
7. Apply power and a ground directly to pump terminals. If pump now operates, clean and repair electrical connections as needed. Replace the pump if it does not operate with direct electrical connections.

HOLD PRESSURE CHECK

Fuel Pump Hold Pressure Check:

WARNING: Before performing this test, relieve fuel pressure as previously described.

1. Disconnect negative battery terminal.
2. Connect fuel pressure gauge to fuel inlet line at fuel rail and plug gauge outlet as shown. Install clamps at hose connections.
3. Reconnect negative battery terminal.
4. Connect a jumper wire across diagnosis connector terminals "F/P" and "GND."
5. Turn ignition switch "ON" for ten seconds to operate fuel pump.
6. Turn ignition switch "OFF" and remove jumper wire.
7. After five minutes, check gauge reading:

HOLD PRESSURE: More than 50 psi (343 kPa)

8. If not as specified, replace pump.

MAXIMUM PRESSURE CHECK

WARNING: Before performing this test, relieve fuel pressure as previously described.

1. Disconnect negative battery terminal.
2. Connect fuel pressure gauge to fuel inlet line at fuel rail and plug gauge outlet as shown. Install clamps at hose connections.
3. Reconnect negative battery terminal.
4. Connect a jumper wire across diagnosis connector terminals "F/P" and "GND."
5. Turn ignition switch "ON" to operate fuel pump. Check gauge reading.

MAXIMUM PRESSURE: 64 - 85 psi (441 - 589 kPa)

6. Turn ignition switch "OFF" and remove jumper wire.
7. If not as specified, replace pump.