Dodge Omni/Horizon/Rampage 1978-1989 Repair Guide

Description of System


The turbocharged Multi-point Electronic Fuel Injection system combines an electronic fuel and spark advance control system with a turbocharged intake system. At the center of this system is a digital, pre-programmed computer known as a Logic Module that regulates ignition timing, air-fuel ratio, emission control devices and idle speed. This component has the ability to update and revise its programming to meet changing operating conditions.

Various sensors provide the input necessary for the Logic Module to correctly regulate fuel flow at the fuel injectors. These include the Manifold Absolute Pressure, Throttle Position, Oxygen Feedback, Coolant Temperature, Charge Temperature, and Vehicle Speed Sensors. In addition to the sensors, various switches also provide important information. These include the Transaxle Neutral-Safety, Heated Rear Window, Air Conditioning, and the Air Conditioning Clutch Switches.

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Fig. Fig. 1 Multi-point injected system components

Inputs to the Logic Module are converted into signals sent to the Power Module. These signals cause the Power Module to change either the fuel flow at the injector or ignition timing or both. The Logic Module tests many of its own input and output circuits. if a fault is found in a major circuit, this information is stored in the Logic Module. Information on this fault can be displayed by means of the instrument panel power loss lamp or by connecting a diagnostic readout tool and observing a numbered display code which directly relates to a general fault.

Most complaints that may occur with this system can be traced to poor wiring or hose connections. A visual check will help stop these faults and save unnecessary test and diagnosis time.