Test Procedure

If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.0L SATURN "L" SERIES article.
If you performed the Fuel Injector Coil Test, go to next step. If not , see FUEL INJECTOR COIL TEST .

NOTE: DO NOT perform this test if the Engine Coolant Temperature (ECT) is above 201°F (94°C).

Observe the ECT with a scan tool. If the ECT is less than 201°F (94°C), go to next step.

NOTE: Verify that adequate fuel is in the fuel tank before proceeding with test procedure.

Turn ignition OFF. Install the Gauge Bar Set. Turn ignition ON, with engine OFF. The fuel pump may need to be commanded ON a few times, in order to obtain the highest possible fuel pressure. DO NOT start the engine. Command the fuel pump ON with a scan tool. Observe the fuel Gauge Bar Set, with the fuel pump commanded ON. If the fuel pressure is 49-55 psi (337-379 kPa), go to next step. If fuel pressure is not 49-55 psi (337-379 kPa), see FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 3.0L SATURN "L" SERIES article.

NOTE: The fuel pressure will drop slightly when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant.

Monitor the Gauge Bar Set for one minute. If fuel pressure decreases by more than 5 psi (34 kPa), see FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 3.0L SATURN "L" SERIES article. If fuel pressure remains constant, go to next step.
1. Connect the Fuel Injector Tester, Injector Tester Adapter Box, and Adapter Box to the fuel injector harness multi-way connector.
2. Set the pulse range to 100 on the fuel injector tester.
3. Command the fuel pump ON and then OFF with a scan tool.
4. Record the fuel pressure indicated by the Gauge Bar Set after the fuel pressure stabilizes. This is the first pressure reading. Record the fuel pressure value immediately after the fuel injector stops pulsing. The fuel pressure may rise after the fuel injector stops pulsing. DO NOT record the higher fuel pressure value.
5. Energize the fuel injector by depressing the Activate Injector button on the Fuel Injector Tester.
6. Record the fuel pressure indicated by the Gauge Bar Set after the fuel injector stops pulsing. This is the second fuel pressure reading.
7. Repeat steps "A" through "F" for each fuel injector.
8. Subtract the second pressure reading from the first pressure reading for one fuel injector. The result is the pressure drop value.
9. Obtain a pressure drop value for each fuel injector.
10. Add all of the individual pressure drop values. This is the total pressure drop.
11. Divide the total pressure drop by the number of fuel injectors. This is the average pressure drop.
Does any fuel injector have a pressure drop value that is more than the average pressure drop or less than the average pressure drop by 1.5 psi (10 kPa). If yes, go to next step. If no, see SYMPTOMS in TROUBLE SHOOTING - NO CODE - 3.0L SATURN "L" SERIES article.
Replace the affected fuel injector. See FUEL RAIL & INJECTORS under FUEL SYSTEMS in REMOVAL & INSTALLATION - SATURN "L" SERIES article. If you completed the fuel injector replacement, go to next step.
Operate the system in order to verify the repair. Did you correct the condition? If yes, system okay, If no, see SYMPTOMS in TROUBLE SHOOTING - NO CODE - 3.0L SATURN "L" SERIES article.