Fuel Line Pressure
- Install Fuel Pressure Gauge (49 UN01 010) to fuel pressure relief valve (Schrader valve) located on fuel rail. Turn ignition on with engine off. Connect New Generation Star (NGS) scan tool to data link connector 2. Connector is located under left side of instrument panel, right of steering column. Using scan tool, select ACTIVATE COMMAND MODES. Select OUTPUT TEST MODE. Press MODE to change to ALL ON mode. Press start to run fuel pump. Turn relay off. Observe fuel pressure.
- Fuel pressure should be 35-40 psi (2.5-2.8 kg/cm2 ). If pressure is zero or low, check fuel pump. See FUEL PUMP. If fuel pump is okay, check for plugged or restricted fuel line or fuel filter. If pressure is high, check for high pressure in fuel pressure regulator. See FUEL PRESSURE REGULATOR HIGH PRESSURE heading below.
- Wait one minute and observe fuel pressure. Fuel pressure should be within 5 psi (.35 kg/cm2 ) of reading in step 2). If fuel pressure is not as specified, check fuel pressure regulator diaphragm. See FUEL PRESSURE REGULATOR DIAPHRAGM heading below. Also, check for injector fuel leakage. See INJECTOR FUEL LEAKAGE heading below. If fuel pressure is as specified, check fuel line pressure under load. See FUEL LINE PRESSURE UNDER LOAD heading below.