Fuel Control

1987 Jeep Cherokee LimitedSECTION Fuel Control

The fuel control system handles the actual delivery of fuel into the engine. See Fig 1 . Fuel from the pump enters the fuel rail, injectors and pressure regulator. Based upon a manifold vacuum signal, the pressure regulator maintains a constant fuel pressure in the system of approximately 31-39 psi (2.1-2.7 kg/cm2 ) by allowing excess fuel to return to the fuel tank.

Fuel injectors are electrically operated solenoid valves which are powered by the ECU. The ECU determines injector pulse width ("on" time) based upon input from the various sensors.

Fig 1: Fuel Control Components
G12546Courtesy of AMERICAN MOTORS/JEEP CORP.
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.