Checking Fuel Delivery: Testing
- Turn ignition on. Using scan tool, actuate ASD fuel system test. Listen for fuel pump operation at fuel tank. It may be necessary to use a stethoscope. If fuel pump operation can be heard, fuel pump is operating. Stop fuel system activation and go to next step. If fuel pump operation cannot be heard, stop fuel system activation and go to step 7 .
- Release fuel pressure. See FUEL SYSTEM PRESSURE RELEASE . Connect a fuel pressure gauge to test port on fuel rail. Using scan tool, actuate ASD fuel system test. Observe fuel pressure gauge. Fuel pressure should be 53-63 psi (365-434 kPa). Stop ASD fuel system test. If fuel pressure is less than specification, go to next step. If fuel pressure is within specification, go to step 5 . If fuel pressure is more than specification, replace fuel filter/pressure regulator. See FUEL FILTER/FUEL PRESSURE REGULATOR under FUEL SYSTEMS in REMOVAL & INSTALLATION - CONCORDE, INTREPID & 300M article.
- Release fuel pressure. Raise and support vehicle. Disconnect fuel pressure line from fuel filter/pressure regulator at fuel tank. Connect Fuel Line Adapter (6539) between disconnected fuel line and fuel pump module. Connect fuel pressure gauge to fuel line adapter hose. Turn ignition on. Using scan tool, actuate ASD fuel system test and note fuel pressure. Fuel pressure should be 53-63 psi (365-434 kPa). Stop ASD fuel system test. If fuel pressure is as specified, repair or replace fuel supply line as necessary. If fuel pressure is not as specified, go to next step.
- Release fuel pressure. Remove fuel pump module and inspect fuel inlet strainer. See FUEL PUMP MODULE under FUEL SYSTEMS in REMOVAL & INSTALLATION - CONCORDE, INTREPID & 300M article. If fuel inlet strainer is plugged, replace fuel pump inlet strainer. If fuel inlet strainer is not plugged, replace fuel pump module.
- Turn ignition off. Release fuel pressure. Disconnect fuel supply line from fuel rail. Install Fuel Line Adapter (6539 for 5/16" fuel lines or 6631 for 3/8" fuel lines) between disconnected fuel line and fuel rail. Insert other end of hose into a graduated container suitable for gasoline.CAUTION: DO NOT operate fuel pump longer than 7 seconds.
- Using scan tool, actuate ASD fuel system test for 7 seconds. If fuel volume is .5 pt (.25L) or more, no problem is indicated at this time. Test is complete. If fuel volume is less than .5 pt (.25L), check for a kinked fuel line between fuel pump module and fuel rail. Repair fuel lines as necessary and retest. If fuel line is okay, replace fuel pump module. See FUEL PUMP MODULE under FUEL SYSTEMS in REMOVAL & INSTALLATION - CONCORDE, INTREPID & 300M article.
- Turn ignition off. Disconnect fuel pump module harness connector. Inspect connector for damage or corrosion. Clean or repair connector as necessary. If connector is okay, turn ignition on. Using scan tool, actuate ASD fuel system test. Connect a test light between ground and fuel pump relay output circuit (Dark Green/White wire) at fuel pump module harness connector. See Fig 1 . If test light illuminates brightly, go to next step. If test light does not illuminate brightly, go to step 10 .
- Turn ignition off. Connect a test light between battery positive terminal and ground circuit (Black wire) at fuel pump module harness connector. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open in ground circuit. See WIRING DIAGRAMS .
- At this time, fuel pump module is assumed to be defective. Replace fuel pump module.
- Turn ignition off. Remove fuel pump relay from Power Distribution Center (PDC). See Figure . PDC is located in engine compartment. See Figure . Connect a test light between ground and fused battery voltage circuit (Red wire) at terminal "B" at fuel pump relay harness connector in PDC. If test light illuminates, go to next step. If test light does not illuminate, repair open in fused battery voltage circuit.
- Measure resistance of fuel pump relay output circuit (Dark Green/White wire) between fuel pump module harness connector and terminal "D" at fuel pump relay harness connector in PDC. If resistance is less than 5 ohms, replace fuel pump relay. If resistance is 5 ohms or more, repair open in Dark Green/White wire between fuel pump module and PDC.