Hard Start Fuel System

HARD START FUEL SYSTEM

Special Tools:

For a complete wiring diagram, refer to the Wiring Information.

WARNING: Follow these safety precautions to reduce the risk of fire and serious possible serious or fatal injury when performing this test procedure.
- Fuel or fuel vapors are highly flammable. A fire could occur if an ignition source is present. Do not expose the fuel or the test equipment used in this procedure to open flames or sparks.
- Inhalation of fuel vapors could lead to disorientation and personal injury. Keep the service area well ventilated, or perform this test procedure in an area where there is a building exhaust removal system.
- Relieve fuel system pressure before servicing fuel system components.
- Use extreme caution when connecting and disconnecting fuel lines.
- Considerable fuel leakage may occur when servicing the fuel system. Wear protective eye wear and clothing to protect from fuel splash, and take suitable fuel containment measures.
- Wrap a shop towel around the fuel pressure gauge connection to absorb fuel leakage that occurs when connecting the test equipment. Place the towel in an approved container when complete.
- Never store fuel in an open container due to the possibility of fire or explosion. Have a dry chemical (Class B) fire extinguisher nearby.

1. CHECK FUEL DELIVERY SYSTEM FOR LEAKS AND DAMAGE

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.

1. Visually and physically inspect the fuel delivery system for external leaks and damage.

Is the system leaking or damaged?

Yes

- Repair / replace as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 2

2. INSTALL APPROPRIATE FUEL LINE ADAPTERS / FITTING FROM GAS AND DIESEL FUEL PRESSURE/DECAY TESTER 8978A

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.

1. Connect Gas and Diesel Fuel Pressure/Decay Tester , Fuel Inlet Hose(1), and Fuel Outlet Hose (2) to the Fuel Line Adapters / Fitting.
2. Connect Drain Extension Hose 535680 (3) to the Fuel Pressure Gauge Assembly Drain Hose (5).
3. Connect the Reservoir Assembly 534960 (4) to the Drain Extension Hose 535680 (3).

WARNING: To reduce the risk of fire and serious possible serious or fatal injury, place Reservoir Assembly 534960 (4) on the floor and out of the way so that it is not a trip hazard.

Proceed

- Go To 4

4. CHECKING FUEL PRESSURE

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.

1. Turn the ignition off.
2. Install the Fuel Pressure Decay Tester on the fuel line near the intake manifold
3. Perform the following procedure to purge air from the system:
- Open the Fuel System Isolation Valve (1).
- Close the Flow Test Valve (2).
- Ignition on, engine not running.
- With the scan tool, actuate the fuel pump.
- Open the Flow Test Valve (1) for 10 seconds, then close the Valve.
- CAUTION: Stop All Actuations.
- Turn the ignition off.
- Disconnect, empty and then reconnect the Reservoir Assembly.

4. Ignition on, engine not running.
5. With the scan tool, actuate the ASD Fuel System test and observe the fuel pressure gauge.

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

Choose a conclusion that best matches your fuel pressure reading.

Below Specification

- Go To 5

Within Specification

- Go To 7

5. RESTRICTED FUEL SUPPLY LINE

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.

1. Turn the ignition off.
2. Remove the Fuel Pressure Decay Tester.
3. Raise the vehicle on a hoist and disconnect the fuel supply line at the fuel pump module.
4. Install the Fuel Pressure Decay Tester at the fuel pump.
5. Perform the following procedure to purge air from the system:
- Open the Fuel System Isolation Valve (1).
- Close the Flow Test Valve (2).
- Ignition on, engine not running.
- With the scan tool, actuate the fuel pump.
- Open the Flow Test Valve (1) for 10 seconds, then close the Valve.
- CAUTION: Stop All Actuations.
- Turn the ignition off.
- Disconnect, empty and then reconnect the Reservoir Assembly.

6. Ignition on, engine not running.
7. With the scan tool, actuate the ASD Fuel System test and observe the fuel pressure gauge.

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

Is the fuel pressure within specification?

Yes

- Visually and physically inspect the fuel supply lines between the fuel tank and the fuel rail. Repair/replace as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 6

6. CHECKING THE FUEL INLET STRAINER

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.

1. Turn the ignition off.
2. Remove the Fuel Pump Module and inspect the Fuel Inlet Strainer.

Is the Fuel Inlet Strainer plugged?

Yes

- Replace the Fuel Pump Inlet Strainer.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Replace the Fuel Pump Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

7. FUEL PUMP MODULE

NOTE: Before continuing visually and physically inspect the fuel delivery system for external leaks or damage. Repair / replace as necessary.

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.

1. Turn the ignition off.
2. Install the Fuel Pressure Decay Tester at the intake manifold.
3. Start the engine and allow the fuel system to reach maximum pressure.
4. Turn the ignition off.
5. Close the Fuel System Isolation Valve and then wait five minutes before proceeding.

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

6. Read the Fuel Inlet and Fuel Outlet Pressure Gauges. The pressure should not drop more than 10 psi on either gauge.
7. Monitor the fuel pressure gauge for a minimum of five minutes.

Does the fuel pressure drop more than 10 psi?

Yes - On Fuel Inlet Gauge

- Replace Fuel Pump Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

Yes - On Fuel Outlet Gauge

- Replace the leaking fuel injector(s).
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- If directed here by another test, return to that test. Otherwise, test complete.