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Home >> Isuzu >> 1991 >> Impulse RS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Testing - EFI >> Fuel System >> Fuel Pressure & Fuel Pump Relay Tests >> Fuel Pressure

Fuel Pressure

  1. Relieve fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE under FUEL SYSTEM. Attach Fuel Pressure Gauge Set (J-34730-1) and Adapter (J-35957-1) to outlet side of fuel filter. Disconnect pressure regulator vacuum hose. Turn ignition on. Allow fuel pump to run for about 10 seconds.
  2. Fuel system pressure should be about 35-38 psi (2.5-2.7 kg/cm2 ). Start engine and check for leaks. Connect pressure regulator vacuum hose. If engine will not start, fuel pump relay can be by-passed. Also see DIAGNOSTIC CHARTS, CHART A-3/ENGINE CRANKS BUT WILL NOT RUN, in this article. With engine idling, fuel pressure should be 25-30 psi (1.8-2.1 kg/cm2 ).
NOTE: To test fuel pump relay circuit, see DIAGNOSTIC CHARTS, CHART A-5/FUEL PUMP RELAY CIRCUIT, in this article.
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