Fuel Pump Test Shadow/SUNDANCE Convertible (Early 2.5L TBI)

NOTE: Perform fuel pump test with fuel tank at least half full. Before disconnecting fuel line during testing, relieve fuel pressure. Maximum output pressure of fuel pump is 135 psi (9.5 kg/cm² ). Pressure is regulated at the fuel rail by pressure regulator.

Relieve fuel pressure. See RELIEVING FUEL PRESSURE under FUEL SYSTEM. Disconnect 5/16" fuel supply hose. Connect fuel system Pressure Gauge (C-4799-B) between fuel supply hose and engine fuel line.
Turn ignition on. Using Diagnostic Readout Box II (DRB-II), select ASD FUEL SYSTEM TEST to activate fuel pump. If fuel pump pressure is at specification, fuel system is functioning properly. See FUEL PUMP PRESSURE SPECIFICATIONS .
If fuel pressure is as specified, record pressure and remove gauge. Install fuel pressure gauge in fuel supply line at rear of vehicle, between fuel tank and fuel filter.
Using DRB-II, reactivate fuel pump and record pressure reading. If fuel pressure is at least 5 psi (.4 kg/cm² ) higher than first pressure reading, replace fuel filter.
If there is no change in pressure reading, gently squeeze fuel return hose. If fuel pressure increases, replace fuel pressure regulator. If no change in fuel pressure is observed, fuel pump filter sock is plugged or fuel pump is defective.
If fuel pressure is greater 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, reactivate 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 greater than specification, remove fuel return hose from throttle body. Connect a substitute hose to throttle body return nipple. Place other end of hose in an approved container.
Using DRB-II, activate fuel pump. If fuel pressure is now within specification, check for a restricted fuel return line between throttle body and fuel tank. If no change in pressure is observed, replace fuel pressure regulator.