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Chart A-7 Fuel System Routing:

Chart A-7 Fuel System Pressure Test:

CIRCUIT DESCRIPTION:

The fuel pump delivers fuel to the fuel rail and injectors, where the system pressure is controlled from 245 to 286 kPa (35-42 psi) by the pressure regulator. Excess fuel is returned to the fuel tank. When the engine is stopped, the pump can be energized by jumping the fuel pump relay connector with a fused lead.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. Use pressure gauge J 34730-1 and adapter J 35957-10. Wrap a shop towel around the fuel pressure tap to absorb any small amount of fuel leakage that may occur when installing the gauge. (The pressure will not leak down after the fuel pump is stopped on a correctly functioning system).

2. While the engine is idling, manifold pressure (vacuum) is low. When applied to the fuel regulator diaphragm, the pressure will result in a lower fuel pressure of about 190-200 kPa (25-30 psi).

3. The application of vacuum to the pressure regulator should result in a fuel pressure drop.

4. Pressure leak-down may be caused by one of the following:

^ In-tank fuel pump check valve not holding.
^ Pump coupling hose leaking.
^ Fuel pressure regulator valve leaking.
^ Injector sticking open/leaking.

DIAGNOSTIC AIDS:

Improper fuel system pressure may contribute to one or all of the following symptoms:

- Cranks but won't run.
- DTC 44 or 45.
- Cutting out (May feel like ignition problem).
- Hesitation, loss of power or poor fuel economy.
For more information, refer to Diagnosis By Symptom (Fuel Related) Symptom Related Diagnostic Procedures

The follow procedure outlines the installation and removal of the Fuel Pressure Gauge Assembly. Make certain to observe all "Cautions" while performing this procedure.

REQUIRED TOOLS:

Port Fuel Pressure Gauge J 34730-1
Fuel Rail Adaptor J 38347

CAUTION: To reduce the risk of fire and personal injury, relieve fuel system pressure before disconnecting the fuel lines. Loosen the fuel filler cap to relieve tank pressure. Remove the circuit opening relay, located under the console in front of the shift lever. Crank the engine and allow it to run until it stalls. Engage the starter for 30 seconds. Use a shop towel to collect fuel during the fuel line disconnection, place the towel in an approved container.

FUEL PRESSURE GAUGE INSTALLATION:

1. Ignition "OFF." Disconnect the negative battery cable.
2. CAREFULLY, Remove the cold start injector valve fuel line hold down bolt, at the fuel rail.
3. Install adapter J 38347 and tighten securely.
4. Install fuel pressure gauge J 34370-1 and tighten securely.
5. Reconnect the negative battery cable.
6. Reinstall the circuit opening relay.
7. Start the engine and look for leaks.
8. Purge the air from the fuel pressure gage into an approved container.

FUEL PRESSURE GAUGE REMOVAL:

1. Remove the negative battery cable.
2. Purge fuel pressure from the fuel pressure gauge into an approved container.
3. CAREFULLY disconnect the fuel pressure gauge.
4. Remove the adapter.
5. Reinstall the fuel line hold down bolt. Tighten to specifications.
6. Reconnect the negative battery cable.
7. Start the engine and check for fuel leaks.