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Home >> Jaguar >> 1987 >> XJ6 Base >> Repair and Diagnosis >> Engine Performance >> System >> Fuel Injection System - LUCAS/BOSCH AFC >> Testing >> Fuel Pressure
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Fuel Pressure

  1. Depressurize fuel system by removing fuel pump relay and cranking engine for a few seconds. Turn ignition switch off and connect fuel pump relay.
  2. Disconnect fuel rail at cold start injector and connect fuel pressure gauge. Disconnect negative lead from ignition coil and turn ignition switch on. Pressure reading should be 35.5-37 psi (2.5-2.6 kg/cm2 ).
  3. Slow pressure drop is permissible; sudden pressure drop requires check of entire fuel system for leaks. After testing fuel pressure, depressurize fuel system, remove test equipment and reconnect fuel lines and ignition coil negative lead.
  4. Operate fuel change-over switch on dash and recheck reading. Reading from both fuel tanks should agree. On all models, if pressure reading is not to specifications, replace fuel pressure regulator.