Grand Cherokee & Wrangler
- Perform FUEL PRESSURE TEST . If fuel pressure is okay, relieve fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE . Ensure area around fuel supply line and fuel rail are clean.
- Disconnect fuel supply line from fuel rail. Install Fuel Line Pressure Test Adapter Hose (6539 for 5/16" fuel lines or 6631 for 3/8" fuel lines) between disconnected fuel line and fuel rail. See Fig 1 . Remove fuel fill cap. Insert other end of hose into a graduated container suitable for gasoline.
- Connect scan tool to data link connector. Using scan tool, actuate fuel pump. A good fuel pump will deliver at least 0.5 pt. (0.25L) of fuel in 7 seconds. Do not operate fuel pump for longer than 7 seconds with fuel line disconnected, as fuel pump module reservoir may run empty. If fuel capacity is not as specified, but fuel pump can be heard operating through fuel fill pipe, 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 and fuel pressure is okay, but capacity is low, replace fuel filter/fuel pressure regulator. On Wrangler, fuel filter/fuel pressure regulator is located in top of fuel tank. See FUEL FILTER/FUEL PRESSURE REGULATOR under FUEL SYSTEMS in REMOVAL & INSTALLATION - WRANGLER article. On Grand Cherokee, fuel filter/pressure regulator is located in front of fuel tank, above rear axle. See Figure . On all models, if fuel pressure and capacity are low, replace fuel pump module assembly. See FUEL PUMP MODULE under FUEL SYSTEMS in appropriate REMOVAL & INSTALLATION article.
CAUTION:
DO NOT operate fuel pump longer than 7 seconds.