Fuel Pump Pressure Test

1998 Isuzu Hombre S, 2.2 4, AutomaticSECTION 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  .
  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 appropriate FUEL SYSTEM DIAGNOSIS  procedure. Locate and repair leak or restriction in fuel system.
FUEL PUMP PERFORMANCE

Application Specification
Amigo, Rodeo, Passport, Trooper & SLX
Operating Pressure 42-55 psi (3.0-3.9 kg/cm2 )
Pressure Drop 3-15 psi (0.2-1.1 kg/cm2 )
Hombre
Operating Pressure 41-47 psi (2.9-3.3 kg/cm2 )
Pressure Drop 3-10 psi (0.2-0.7 kg/cm2 )
Fig 1: Installing Fuel Pressure Gauge (Typical)
G96G10104Courtesy of ISUZU MOTOR CO.
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.