Engine management system - MEMS (Fuel system): Description and operation

FUEL SYSTEM

Engine Control Module (ECM)

The Modular Engine Management System (MEMS) is controlled by an ECM mounted in the engine compartment. The ECM is an adaptive unit which over a period of time learns the load and wear characteristics of the engine it controls. The ECM remembers and updates two main engine requirements when the engine is running at normal operating temperature:

1. The position of the idle air control (IAC) valve required to achieve a specified idle speed. This is then used as a reference for IAC valve movement to achieve idle speed under all load conditions.
2. The fuelling change or offset required to achieve a set oxygen sensor voltage. This allows the system to provide the correct fuelling without having to apply excessive adjustments to the fuelling which can adversely affect the emissions and driveability.

NOTE: After fitting a different ECM, TestBook will be required to reprogramme the ECM with the code from the anti-theft control unit and to perform a full engine tune procedure.

The ECM inputs and outputs are shown in the following table: