1989 GMC Forward Control 6.2 J, StandardFACTORY OEM SERVICE PROCEDURE

Fuel Injection System - TBI: Description

The throttle body fuel injection system consists of 7 major sub-assemblies: fuel supply system, throttle body assembly, Idle Air Control (IAC) system, Electronic Control Module (ECM), Electronic Spark Timing (EST), data sensors, and emission controls. Fuel is supplied to the engine through electronically pulsed injector(s), located in the throttle body assembly on top of intake manifold. The ECM controls the amount of fuel metered through the injector(s) based upon engine demand.

Fig 1: Throttle Body Identification Location
G10509Courtesy of GENERAL MOTORS CORP.
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:

  • 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.

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