2002 Jeep Wrangler SE, AutomaticFACTORY OEM SERVICE PROCEDURE

Fuel Pump Capacity Test: Liberty

  1. 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.
  2. 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 Figure . Remove fuel fill cap. Insert other end of hose into a graduated container suitable for gasoline.
  3. Connect scan tool to Data Link Connector (DLC). DLC is located below instrument panel, near steering column. Using DRBIII(R), actuate fuel pump and pressurize system. A good fuel pump will deliver at least .5 pt. (.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.
  4. If capacity is lower than specification, but fuel pump can be heard operating through fuel fill cap opening, check for a kinked/damaged fuel supply line somewhere between fuel rail and fuel pump module. Repair fuel line as necessary and retest. If line is not kinked/damaged, and fuel pressure is okay, but capacity is low, replace fuel filter. See FUEL FILTER under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION article.
  5. If both fuel pressure and capacity are low, replace bottom section of fuel pump module. See FUEL PUMP MODULE under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION article.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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