3.3L Fuel Pump Test
- Release fuel pressure. See FUEL PRESSURE RELEASE in this article. Remove cap from service valve on fuel rail. Connect fuel system pressure Gauge (C-4799-A) to service valve.
- Turn ignition on. Using DRB-II (C-4805), activate fuel pump. See FUEL PUMP PRESSURE SPECIFICATIONS in this article. If fuel pump pressure is at specification, fuel system is functioning properly.
- If fuel pressure is not to specification, record pressure and remove gauge. Using DRB-II, activate fuel pump. Ensure no fuel leaks from service valve. Install cap on service valve.
- If fuel pressure is not to specification, install pressure gauge in fuel supply line between fuel tank and fuel filter at rear of vehicle. Using DRB-II, activate fuel pump.
- Record pressure reading. If fuel pressure is 5 psi (.4 kg/cm2 ) higher than first pressure reading, replace fuel filter. If no change in pressure reading is observed, gently squeeze fuel return hose.
- If fuel pressure increases, replace fuel pressure regulator. If no change in fuel pressure is observed, problem is plugged fuel pump filter sock or defective fuel pump.
- If fuel pressure is more than specification, remove fuel return hose at rear of vehicle. Connect an extension hose to return hose. Place hose in an approved container with at least a 2 gallon capacity.
- Using DRB-II, activate fuel pump. If fuel pressure is now within specification, check in-tank return fuel hose for kinking. Replace fuel tank assembly if in-tank reservoir check valve or aspirator jet is plugged.
- If fuel pressure is still more than specification, remove fuel return hose from pressure regulator. Connect a substitute hose to fuel pressure regulator. Place other end of hose in an approved container.
- Using DRB-II, activate fuel pump. If fuel pressure is at specification, check for a restricted fuel return line. If no change was observed, replace fuel pressure regulator.