Test NTC-7: Checking Fuel Delivery

NOTE: For circuit identification, see WIRING DIAGRAMS article. After each repair procedure has been completed, reconnect all components. Perform TEST VER-1 to ensure system is functioning properly. Ensure no DTCs are present before performing this test.

WARNING: Fuel system is under high pressure and fuel pressure must be released before opening fuel system. See FUEL SYSTEM PRESSURE RELEASE .

Turn ignition off. Release fuel pressure. On 2.7L engine, use Adapter (6539) between fuel rail and fuel supply line, then connect Fuel Pressure Gauge (C-4799-B) to adapter. On 3.2L and 3.5L, connect Fuel Pressure Gauge (C-4799-B) to fuel rail. On all vehicles, turn ignition on. Using scan tool, actuate ASD fuel system test. Observe and record fuel pressure. Fuel pressure should be 54-64 (3.8-4.5 kg/cm² ). Stop fuel system activation. If fuel pressure is less than specified, go to next step. If fuel pressure is as specified, go to step 7. If fuel pressure is more than specified, replace fuel filter/pressure regulator.
Turn ignition off. Remove rear seat to access fuel pump module 10-pin C308 in-line connector. Disconnect fuel pump module 10-pin C308 connector. Visually inspect connector for corroded, damaged, pushed-out or miswired terminals. Repair connector as necessary. If connector is okay, turn ignition on. Using scan tool, actuate ASD fuel system test. Using a test light connected to ground, probe Dark Green/White wire at C308 harness connector. If test light illuminates brightly, stop fuel system activation and go to next step. If test light is not illuminated or is not bright, repair high resistance or open in Dark Green/White wire between C308 connector and terminal "D" at fuel pump relay socket in PDC. See Figure.
Turn ignition off. With a test light connected to positive battery terminal, probe Black wire at C308 harness connector. If test light illuminates brightly, reconnect C308 connector and go to next step. If test light is not illuminated or is not bright, repair high resistance or open in Black wire between C308 connector and ground. Ground is located under passenger's seat.
Inspect fuel supply line between fuel tank and fuel rail for signs of damage or restrictions. If no signs of damage or restrictions exist in fuel supply line, go to next step. If signs of damage or restrictions exist in fuel supply line, repair or replace fuel supply line as necessary.
Remove fuel pump module from fuel tank. See FUEL PUMP MODULE under FUEL SYSTEMS in appropriate REMOVAL, OVERHAUL & INSTALLATION article. Inspect fuel pump inlet strainer on bottom of fuel pump module for restrictions. If fuel pump inlet strainer is not restricted, replace fuel pump module. If fuel pump inlet strainer is restricted, replace fuel pump inlet strainer.
At this time, fuel pump module is assumed to be defective. Replace fuel pump module.
Turn ignition off. Release fuel pressure. Disconnect fuel supply from fuel rail. Connect Fuel Line Adapter (6539 for 5/16" fuel line or 6631 for 3/8" fuel line) to disconnected fuel supply line. Place other end of fuel line adapter in graduated cylinder. Turn ignition on. Using scan tool, actuate ASD fuel system test to operate fuel pump for no more than 7 seconds and note fuel pump volume. DO NOT operate fuel pump for more than 7 seconds or fuel pump may be damaged. Stop ASD fuel system test and go to next step.
Fuel pump volume should be at least .52 pint (.25 liter) in 7 seconds. If fuel pump volume is as specified, remove fuel line adapter, reconnect fuel supply line. Test is complete. If fuel pump volume is not as specified, remove fuel line adapter and reconnect fuel supply line. Check for restricted fuel supply line between fuel rail and fuel pump module on top of fuel tank. If no kinks or restrictions exist in fuel supply line, improper fuel pump volume may be caused by restricted fuel pump inlet strainer on bottom of fuel pump module or defective fuel pump module. Replace components as necessary.