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Home >> Saab >> 1991 >> 900 SPG >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Testing >> Fuel System >> Fuel Pressure >> Fuel Pump Delivery Pressure
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Fuel Pump Delivery Pressure

  1. Turn ignition off. Disconnect banjo coupling at inlet to fuel injection manifold. Connect a fuel pressure gauge using existing seals. Ensure pressure gauge hangs vertically. Turn ignition on. Pinch off fuel return line and check fuel pressure. When line is plugged, there should be an immediate increase in fuel pressure.
    CAUTION: DO NOT  allow pressure to rise above 83 psi (5.8 kg/cm2 ).
  2. If fuel pressure does not increase, check for the following problems:
    • At least 11.5 volts across fuel pump terminals
    • Obstructed fuel lines
    • Clogged fuel filter
    • Fuel filter installed backward
    • Defective relief valve in fuel pump
      NOTE: If fuel filter has been installed backward, it must be replaced.
  3. After checking fuel pump pressure, turn ignition off. Go to FUEL PUMP DELIVERY FLOW  test procedure (do not disconnect pressure gauge).