| STEP |
INSPECTION |
ACTION |
| 1 |
CHECK SYSTEM INTEGRITY
- Visually inspect the complete fuel delivery system, including fuel lines, connections, relays, damage to fuel tank, fuel pump, fuel pressure regulator, fuel pulse damper and fuel injector areas for leaks, looseness, cracks, kinks, pinching, or abrasion caused by a collision or mishandling.
- Visually inspect electrical harnesses and connectors for loose pins, corrosion, abrasion, or other damage from collision or mishandling.
- Verify vehicle has followed maintenance schedule.
- Verify fuel pump shutoff switch is set. See FUEL PUMP SHUTOFF SWITCH RESET INSTRUCTIONS (B2500, B3000 & B4000)
.
- Verify battery is fully charged (12.5 volts or greater).
- Verify electrical/fuse integrity.
- Verify fuel level is sufficient.
- Has any concern been found?
|
Yes |
Repair as necessary.
Rerun quick test.
See
ON-BOARD DIAGNOSTIC TESTS
. |
| No |
Go to step 2. |
| 2 |
CHECK FOR VOLTAGE AT FUEL PUMP HARNESS CONNECTOR
- NGS Tester connected.
- Verify fuel pump shutoff switch state. Follow the fuel pump shutoff switch reset procedure. See FUEL PUMP SHUTOFF SWITCH RESET INSTRUCTIONS (B2500, B3000 & B4000)
.
- Disconnect fuel pump harness connector at the fuel pump.
- Key ON, Engine OFF (KOEO).
- Connect a multimeter between fuel pump power circuit (P/B) and fuel pump ground (B/Y) circuit at the fuel pump harness connector B-422
- Enter Output Test Mode and turn on fuel pump circuit and monitor the voltage reading.
- Was the voltage greater than 12.5 volts?
|
Yes |
Exit Output Test Mode.
Reconnect fuel pump harness connector.
Restore vehicle.
Go to step 3. |
| No |
Check for opens and shorts in the fuel pump power and ground circuits.
Restore vehicle. |
| 3 |
CHECK FUEL FILTER FOR PROPER MAINTENANCE
- Locate and inspect the vehicle maintenance schedule and fuel filter. Check for last service date.
- Was the fuel filter serviced in the last 1609 Km (1000 miles)?
|
Yes |
Go to step 4. |
| No |
Replace fuel filter.
See FUEL SYSTEM
in REMOVAL, OVERHAUL, & INSTALLATION article in Engine Performance
.
Go to step 4. |
| 4 |
CHECK FUEL PRESSURE
WARNING:
Before servicing or replacing any components in the fuel system, reduce the possibility of injury or fire by following direction in fuel system caution, handling and warning at the beginning of this test.
|
Yes |
Go to step 5. |
| No |
For fuel system with more than 448 kPa (65 psi):
Replace fuel pump.
See FUEL SYSTEM
in REMOVAL, OVERHAUL, & INSTALLATION article in Engine Performance
.
Restore vehicle.
Recheck fuel pressure.
For fuel system with less than 310 kPa (45 psi): Go to step 7. |
| 5 |
CHECK FUEL INJECTOR FLOW AND LEAKAGE
- Check injectors for leakage and flow rate using an injector tester
- Flow rate specification: 6.4 kg/hr (14 lb/hr), 3.0L Flexible Fuel 8.6 kg/hr (191b/ hr)
- Is the flow rate and leakage rate for the injectors tested within specification?
|
Yes |
Verify no other leak exists. Replace fuel pump.
See FUEL SYSTEM
in REMOVAL, OVERHAUL, & INSTALLATION article in Engine Performance
. |
| No |
Replace failed fuel injector(s).
See FUEL SYSTEM
in REMOVAL, OVERHAUL, & INSTALLATION article in Engine Performance
.
Restore vehicle.
Recheck fuel pressure. |
| 6 |
CHECK PRESSURE REGULATOR AND PULSE DAMPER DIAPHRAGM
- Install fuel pressure tester.
- Start engine and run engine for 10 seconds.
- Key OFF, wait 10 seconds.
- Start engine and run engine for 10 seconds.
- Key OFF, remove vacuum hose from fuel pressure regulator or pulse damper port.
- Inspect for fuel in the vacuum hose regulator port or pulse damper.
- Is the vacuum hose and regulator or pulse damper port free of fuel?
|
Yes |
Go to step 7. |
| No |
Replace fuel pulse damper. |
| 7 |
CHECK FUEL SUPPLY LINE FOR RESTRICTION
- Observe Warning, Caution and Handling at the beginning of this test.
- Disconnect fuel supply line at the fuel rail.
- Disconnect fuel supply line at the fuel pump.
- Check the fuel supply line for restrictions due to blockage, kinking, or pinching.
- Apply 21-34 kPa (3-5 psi) regulated shop air pressure to the supply line.
- Does air flow freely through the supply line?
|
Yes |
Air flows freely.
Replace fuel pump.
See FUEL SYSTEM
in REMOVAL, OVERHAUL, & INSTALLATION article in Engine Performance
. |
| No |
Repair cause of restriction.
Restore vehicle.
Recheck fuel pressure. |