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Fuel Delivery System

Check System Integrity
- Visually inspect 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.
- Verify battery is fully charged (12.5 volts or more).
- Verify electrical/fuse integrity.
- Verify fuel level is sufficient.
If concern is not present, go to next step. If any concern is found, repair as necessary. After repair, rerun Quick Test. See QUICK TEST under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article.

Check For Voltage At Fuel Pump Harness Connector
- Connect scan tool to DLC-2.
- Verify fuel pump shutoff switch state.
- Disconnect fuel pump assembly pin harness connector at fuel pump.
- Turn ignition on, engine off. Connect a DVOM between fuel pump power circuit (Pink/Black wire) and fuel pump ground circuit (Black wire) at fuel pump assembly pin harness connector.
- Enter OUTPUT TEST MODE to turn on fuel pump circuit and monitor voltage reading.
If voltage reading is more than 12.5 volts, exit OUTPUT TEST MODE. Reconnect fuel pump pin harness connector. Restore vehicle to original condition. Go to next step. If voltage reading is not more than 12.5 volts, check for opens and shorts in fuel pump power and ground circuits. Repair as necessary. After repair, restore vehicle to original condition.

Check Fuel Filter For Proper Maintenance
- Locate and inspect vehicle maintenance schedule and fuel filter.
- Check for last service date.
- If fuel filter was serviced in last 1000 miles, go to next step. If fuel filter was not serviced in last 1000 miles, replace fuel filter. After repair, go to next step.
WARNING: Before servicing or replacing any components in fuel system, reduce possibility of injury or fire by following directions in fuel system warning at beginning of this test.

Check Fuel Pressure
- Install fuel pressure tester.
- Release fuel pressure.
- Connect scan tool to DLC-2. Turn ignition on, engine off.
- Access OUTPUT TEST MODE and run fuel pump to obtain maximum fuel pressure. For fuel pressure specifications, see SPECIFICATIONS INDEX .
  NOTE: Fuel pump will only operate for approximately 8 seconds when Output Test Mode is selected and activated.
If fuel pressure reading is as specified, go to next step. If fuel pressure reading is not as specified:
1. If fuel pressure reading is more than specified, replace fuel pump. After repair, restore vehicle to original condition. Recheck fuel pressure.
2. If fuel pressure reading is less than specified, go to step 7.

Check Fuel Injector Flow And Leakage

Check fuel injectors for leakage and flow rate using an injector tester:
Flow Rate Specification
- 3.0L engine - 5.5 kg/hr (12 lb/hr).
If flow rate and leakage rate for injectors tested is as specified, verify no other leak exists and replace fuel pump. If flow rate and leakage rate for injectors tested is not as specified, replace faulty fuel injector(s). After repair, restore vehicle to original condition. Recheck fuel pressure.

Check Pulse Damper/Fuel Pressure Regulator Diaphragm
- Install fuel pressure tester.
- Start engine and run engine for 10 seconds.
- Turn ignition on, engine off.
- Wait 10 seconds.
- Start engine and run engine for 10 seconds.
- Turn ignition off.
- Remove vacuum hose from pulse damper port (fuel pressure regulator port, on Tribute) and inspect for fuel in vacuum hose.
If vacuum hose and pulse damper port (fuel pressure regulator port, on Tribute) are free of fuel, go to next step. If fuel is found in vacuum hose, pulse damper port or fuel pressure regulator port, replace pulse damper or fuel pressure regulator.
WARNING: Before servicing or replacing any components in fuel system, reduce possibility of injury or fire by following direction in fuel system caution, handling and warning at beginning of this test.

Check Fuel Supply Line For Restriction

Release fuel pressure. Disconnect fuel supply line at fuel rail. Disconnect fuel supply line at fuel pump. Check for restriction in fuel supply line (blockage, kinked or pinched). Using regulated air pressure of 3-5 psi (21-34 kPa), blow air through fuel supply line. If air flows freely, replace fuel pump. If air does not flow freely, repair restriction as necessary. Restore vehicle back to original condition and recheck fuel system.