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

FUEL SYSTEM

Engine control module (ECM)

The Modular Engine Management System (MEMS) is controlled by the Electronic Control Module (ECM) which is located behind the battery in the engine compartment.

The ECM is an adaptive unit and can learn 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 on KV6 engines or the stepper motor on ’T’ series engines, to achieve the specified idle speed. This position is used as a reference for IAC valve or stepper motor movement to achieve idle speed under all conditions.
2. The fuelling change or offset required to achieve a set oxygen sensor voltage. Fuelling is adjusted around a step in the oxygen sensor output. 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 to initialise adopted values.

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