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Fuel Injection System - TBI: Description

The Throttle Body Injection (TBI) system is a single injector system that introduces fuel into the throttle body from above the throttle plate. The injector, located within the throttle body, is controlled by the Electronic Control Unit (ECU).

The ECU is a sealed microprocessor that receives input signals from several sensors and other related engine components. Based on these inputs, the ECU generates output signals that control and adjust air/fuel mixture and ignition timing as necessary to optimize engine performance.

The ECU also controls engine idle speed, emission control systems, the upshift indicator light (manual transmission only), and the A/C compressor clutch.

Fig 1: Jeep/Renix Throttle Body Fuel Injection System Components
G11451Courtesy of AMERICAN MOTORS/JEEP CORP.