Checking the Fuel Delivery System

CHECKING THE FUEL DELIVERY SYSTEM

For a complete wiring diagram refer to the Wiring Information .






1. FUEL PUMP OPERATION
1. Ignition on, engine not running.
2. With a scan tool, actuate the Fuel System test.

NOTE: It may be necessary to use a mechanics stethoscope in the next step.

3. Listen for fuel pump operation at the fuel tank. The fuel pump should operate smoothly with no excessive noise. If the pump has excessive noise such as grinding, the pump should be replaced.

CAUTION: Stop All Actuations.

Does the Fuel Pump sound to be operate normally?

Yes

- Go to 2

No

- Go to 7

2. FUEL PRESSURE
1. Turn the ignition off.

WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

2. Install a fuel pressure gauge.
3. Ignition on, engine not running.
4. With the scan tool, actuate the Fuel Pump and observe the fuel pressure gauge.

NOTE: Fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi).

CAUTION: Stop All Actuations.

Choose a conclusion that best matches your fuel pressure reading.

Below Specification

- Go to 3

Within Specification

- Test Complete.

Above Specification

- Replace the Fuel Pump Module.
- Perform the PCM Verification TestPCM Verification Test

3. RESTRICTED FUEL SUPPLY LINE
1. Turn the ignition off.

WARNING: The fuel system is under a constant pressure even with the engine off. Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released.

2. Raise vehicle on hoist, and disconnect the fuel pressure line at the fuel pump module.
3. Install special tool #6539 (5/16") or #6631(3/8") fuel line adapter and the fuel pressure gauge between the fuel supply line and the fuel pump module.
4. Ignition on, engine not running.
5. With the scan tool, actuate the Fuel Pump and observe the fuel pressure gauge.

NOTE: Fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi).

CAUTION: Stop All Actuations.

Is the fuel pressure within specification now?

Yes

- Repair/replace fuel supply line as necessary.
- Perform the PCM Verification TestPCM Verification Test

No

- Go to 4

4. SADDLE FUEL TANK

Is the vehicle equipped with a saddle type fuel tank?

Yes

- Go to 5

No

- Go to 6

5. CHECKING FUEL TANK SIPHON HOSE AND FUEL LINE
1. Turn the ignition off.

WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

2. Gain access to the Fuel Pump Module and the Fuel Tank Module.
3. Inspect the following fuel components:
- Fuel line and siphon hose between the Fuel Pump Module and the Fuel Tank Module. Look for disconnected and/or damaged lines or hoses.
- Fuel Pressure Regulator not properly seated in the module.

Were the above items in good working condition?

Yes

- Go to 6

No

- Repair or replace as necessary.
- Perform the PCM Verification TestPCM Verification Test

6. CHECKING THE FUEL PUMP INLET
1. Turn the ignition off.

WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

2. Remove the Fuel Pump Module and Fuel Tank Module (if equipped), inspect the Fuel Inlet and the bottom of the fuel tank for debris that could cause the fuel pump inlet to be plugged.

Is the Fuel Pump Inlet plugged?

Yes

- Repair/Replace as necessary.
- Perform the PCM Verification TestPCM Verification Test

No

- Replace the Fuel Pump Module.
- Perform the PCM Verification TestPCM Verification Test

7. FUEL PUMP MOTOR GROUND CIRCUIT




1. Turn the ignition off.
2. Disconnect the Fuel Pump Module harness connector.
3. Using a 12-volt test light to battery voltage, probe the Fuel Pump Motor Ground circuit in the Fuel Pump Module harness connector.

NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly.

Yes

- Replace the Fuel Pump Module.
- Perform the PCM Verification TestPCM Verification Test

No

- Repair the Fuel Pump Motor Ground circuit.
- Perform the PCM Verification TestPCM Verification Test