Fuel System Pressure Leak-Down Test (Grand Cherokee)
- Relieve fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE under FUEL DELIVERY . Connect 5/16" Fuel Line Pressure Test Adapter (6539) or 3/8" Adapter (6631) between fuel supply line and fuel rail. Connect a 0-60 psi (0-4.2 kg/cm2 ) fuel pressure gauge to pressure test port on fuel line pressure test adapter. Start engine, bring to operating temperature and measure fuel system pressure. Shut engine off.
- Wait 5 minutes and check fuel pressure. Fuel pressure should be 24 psi (1.7 kg/cm2 ) or more. If pressure is not as specified, go to next step.
- Start engine, bring to operating temperature and measure fuel system pressure. Shut engine off. Clamp test adapter rubber hose between fuel supply line and pressure gauge. Wait 5 minutes and check fuel pressure. If pressure holds at 24 psi (1.7 kg/cm2 ) or more, go to next step. If pressure does not hold, a fuel injector and/or fuel rail is leaking.
- Start engine, bring to operating temperature and measure fuel system pressure. Shut engine off. Clamp test adapter rubber hose between fuel rail and pressure gauge. Wait 5 minutes and check fuel pressure. If pressure does not hold at 24 psi (1.7 kg/cm2 ) or more, check fuel line between fuel rail, fuel tank and fuel filter for a leak. If no leaks are found, replace fuel pump tank module.