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Home >> Volvo >> 1989 >> 780 GLE, AW71 >> Repair and Diagnosis >> Engine Performance >> System >> System & Component Tests >> Fuel Delivery >> Fuel Pressure Regulator

Fuel Pressure Regulator

  1. Connect a fuel pressure gauge between fuel line and fuel injection manifold.
  2. On 240 DL/GL, remove panel under right side of instrument panel. Disconnect fuel system relay connector. See Fig 1 .
  3. On all models except 240 DL/GL, remove fuel system relay. Fuel system relay is located in fuse/relay box. See Fig 1 .
  4. On all models, energize fuel pump. Connect a jumper wire between terminal No. 30 and No. 87/2. Observe fuel pressure reading. Fuel pressure should read 42 psi (2.0 kg/cm2 ). If pressure is too low, pinch off fuel return line and recheck pressure.
    CAUTION: DO NOT  allow pressure to exceed 84 psi (5.9 kg/cm2 ).
  5. If pressure rises quickly, fuel pump and lines are functioning correctly. Replace pressure regulator and recheck pressure. If pressure does not rise quickly, go to next step.
    Fig 1: Fuel System Relay Locations & Terminal Identification
    G121549Courtesy of VOLVO CARS OF NORTH AMERICA.
  6. If fuel pressure rises slowly, fuel filters or lines are blocked. If pressure does not rise, fuel pump is defective.
  7. If fuel pressure is high, disconnect fuel return line from pressure regulator and blow into line. If line is open, pressure regulator is defective and should be replaced.
  8. Pressure may also be checked with engine off and fuel gauge connected. Attach a hand vacuum pump to pressure regulator. Pump vacuum pump. Line pressure should decrease as vacuum is applied to regulator.