1983 Jaguar XJ-SFACTORY OEM SERVICE PROCEDURE

Fuel System Pressure Test

  1. Depressurize the fuel system by disconnecting fuel pump relay and cranking the engine for a few seconds. Turn ignition off. Connect fuel pump relay. Disconnect cold start injector supply hose from fuel rail. Connect a pressure gauge to open port on fuel rail.
  2. Remove the distributor lead from the ignition coil. Ground terminal 85 of the pump relay. Turn ignition switch "ON" and note the pressure gauge reading. Fuel pressure should be 28-30 psi (2.0-2.2 kg/cm2 ).
  3. If either or both readings are high, check for restricted or plugged return lines. If either or both readings are low, check for blockage in the supply line or a plugged filter.
  4. If no blockage is present, the pressure regulator must be adjusted. If, after adjustment, the proper pressure cannot be obtained, the regulator or fuel pump may need to be replaced.
  5. Turn ignition switch "OFF" and depressurize fuel system. Remove pressure gauge and reconnect fuel line to fuel rail. Turn ignition "ON" and check the fuel system for leaks. Remove the ground connection from terminal 85 of the pump relay and reconnect the distributor lead to the ignition coil.
Factory Service Tools

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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.