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Fuel Pump Pressure Test

NOTE: Begin basic fuel system diagnosis with testing fuel pressure.
  1. Turn ignition off. Ensure A/C is off (if equipped). Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE  . Attach Fuel Pressure Gauge Set (J-34730-1 ) to fuel rail or fuel supply line. See Fig 1 . Turn ignition on. Allow fuel pump to run for about 2 seconds. Check fuel pressure. See FUEL PUMP PERFORMANCE  table.
  2. With engine at normal operating temperature, turn ignition on and let fuel pressure build to maximum pressure. Start engine and observe pressure. See FUEL PUMP PERFORMANCE  . If pressure drop is as specified, system is operating properly. If pressure does not drop as specified, see FUEL SYSTEM DIAGNOSIS  procedure. Locate and repair leak or restriction in fuel system.
FUEL PUMP PERFORMANCE

Application Specification
Operating Pressure 42-55 psi (3.0-3.9 kg/cm2 )
Pressure Drop 3-15 psi (0.2-1.1 kg/cm2 )
Fig 1: Installing Fuel Pressure Gauge (Typical)
G96G10104Courtesy of ISUZU MOTOR CO.