Fuel Pressure Check

1991 Subaru Loyale 4D Sedan, 1.8 5, StandardSECTION Fuel Pressure Check

Basic diagnosis of fuel system should begin with determining fuel system pressure. If fuel pump is inoperative, see appropriate FUEL PUMP CIRCUIT TEST CHART in this article.

WARNING: ALWAYS relieve fuel pressure before disconnecting any fuel injection-related component. DO NOT  allow fuel to contact engine or electrical components. If connecting fuel pressure gauge to fuel system without using a "T" connector, DO NOT  operate fuel pump for more than a few seconds. Operating fuel pump for longer than a few seconds under this condition damages fuel pump.
  1. Disconnect fuel pump connector. Crank engine for at least 5 seconds. If engine starts, let it run until it stops. Disconnect fuel hose at pressure regulator and install fuel pressure gauge using "T" fitting.
  2. Start engine and check fuel pressure at idle. See the REGULATED FUEL PRESSURE  table. Ensure fuel pressure increases as engine RPM increases.
REGULATED FUEL PRESSURE

Application Pressure: psi (kg/cm2 )
Legacy, XT & XT6 26-30 (1.8-2.1)
Loyale
1.8L PFI 26-30 (1.8-2.1)
1.8L TBI 20-24 (1.4-1.7)
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.