Ford Mustang/Capri 1979-1988 Repair Guide

Fuel Injectors


The fuel injector nozzles are electro-mechanical devices which both meter and atomize fuel delivered to the engine. The injectors are mounted in the lower intake manifold and are positioned so that their tips are directing fuel just ahead of the engine intake valves. The injector bodies consist of a solenoid-actuated pintle and needle valve assembly. An electrical control signal from the Electronic Engine Control unit activates the injector solenoid causing the pintle to move inward off its seat, allowing fuel to flow. Since the injector flow orifice is fixed and the fuel pressure drop across the injector tip is constant, fuel flow to the engine is regulated by how long the solenoid is energized. Atomization is obtained by contouring the pintle at the point where the fuel separates.


See Figures 1 and 2

  1. Disconnect the fuel supply and return lines.
  3. Remove the vacuum line from the fuel pressure regulator.
  5. Disconnect the wiring harness.
  7. Remove the fuel injector manifold assembly.
  9. Carefully remove the connector(s) from the individual injector(s).
  11. Grasping the injector body, pull up while gently rocking the injector from side to side.
  13. Inspect the screen filter at the top of each injector. If clogged, replace the complete injector assembly.
  15. Inspect the injector O-rings (two per injector) for signs of deterioration. Replace as needed.
  17. Inspect the injector plastic hat (covering the injector pintle) and washer for signs of deterioration. Replace as needed. If a hat is missing, look for it in the intake manifold.
  19. Installation is the reverse of removal. Lubricate all O-rings with a light oil. Carefully seat the fuel injector manifold assembly on the four injectors and secure the manifold with the attaching bolts. Torque the bolts 15-22 ft. lbs.

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Fig. Fig. 1: Fuel injector-inspection points

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Fig. Fig. 2: Injector assembly with integral filter