Fuel Delivery System Output Test

Fuel Delivery System Output Test

For a complete wiring diagram, refer to.

Follow these safety precautions to reduce the risk of fire and 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 eyewear 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.

Test Step 1 - Check Fuel Delivery System for Leaks and Damage

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.

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

Is the system leaking or damaged?

Yes

• Repair or replace components as necessary.

• Perform the PCM Verification test. Refer to => [ PCM Verification Test ] PCM Verification Test.

No

• Go to Test Step 2

Test Step 2 - Install Fuel Line Adapters/Fittings from Fuel Pressure Decay Tester

• Turn the ignition off.

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.

• Disconnect the frame rail fuel supply line connector between the fuel supply line and the fuel rail.

• Install the appropriate fuel line adapters/fitting from the decay tester.

• Go to Test Step 3

Test Step 3 - Install Fuel Pressure Gauge Assembly

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.

• Connect fuel pressure gauge assembly 8978-1 fuel inlet hose (1) and fuel outlet hose (2) to the fuel line adapters/fitting.

• Connect special tool drain extension hose 535680 (3) to the fuel pressure gauge assembly drain hose (5).

• Connect reservoir assembly 534960 (4) to drain extension hose 535680 (3).

To reduce the risk of fire and 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.

• Go to Test Step 4

Test Step 4 - Check Fuel Pressure

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.

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.

Stop All Actuations!

• Turn the ignition off.

• Disconnect, empty, and then reconnect the reservoir assembly.

• Turn the ignition on, wait 5 seconds, turn the ignition off, and then wait 1 minute before proceeding.

• Read the fuel pressure gauge (3) and record the reading. The fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi).

Is the fuel pressure within specification?

Yes

• Go to Test Step 5

No

• Perform the Fuel Delivery System Test. Refer to => [ Fuel Delivery System Test ] Fuel Delivery System Test.

Test Step 5 - Check Fuel Delivery System Output

Does the amount of fuel in the reservoir meet or exceed the specification?

Yes

• Test complete.

No

• Perform the Fuel Delivery System diagnostic procedure. Refer to => [ Fuel Delivery System Test ] Fuel Delivery System Test.