Fuel Pressure Leak Down

FUEL PRESSURE LEAK DOWN

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 PCM 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

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. Disconnect the frame rail fuel supply line connector between the fuel supply line and the fuel rail.
3. Install the appropriate Fuel Line Adapters / Fitting from Gas and Diesel Fuel Pressure/Decay Tester.

Proceed

- Go To 3

3. INSTALL FUEL PRESSURE GAUGE ASSEMBLY

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. 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.

2. Turn the ignition on, wait five seconds, turn the ignition off and then wait 1 minute before proceeding.
3. Read the Fuel Pressure Gauge (3) and record the reading. Non SRT-4 fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi). SRT-4 fuel pressure specification is 552 KPa +/- 34 KPa (80 psi +/- 5 psi).

Is the fuel pressure within specifications?

Yes

- Go To 5

No

- Perform the Checking The Fuel Delivery System diagnostic procedure as directed.

5. CHECK FUEL DELIVERY SYSTEM FOR LEAK DOWN

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. Close the Fuel System Isolation Valve (1) and then wait five minutes before proceeding.
2. Read the Fuel Inlet (2) and Fuel Outlet (3) Pressure Gauges. The pressure should not drop more than 10 psi on either gauge.

Does the fuel pressure drop more than 10 psi?

Yes - On Fuel Inlet Gauge (1)

- Replace the fuel pump module.
- Perform the PCM VERIFICATION TEST. Powertrain Verification Test.

Yes - On Fuel Outlet Gauge (2)

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

No

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