System Description

Motronic 2.10.2 Engine Management System:

PURPOSE
Motronic is an electronic fuel injection/ignition management system whose main functions are to control:
^ Fuel Injection
^ Ignition
^ Idle speed
^ EVAP System

OPERATION
Unlike earlier systems, Motronic is "sequential" injection. The ECM determines not only the correct quantity of fuel for each cylinder, but the correct injection time as well.

ECM Highlights
- capable of controlling ignition timing for individual cylinders.

- uses a microprocessor to convert input signals into the necessary output functions.

- incorporates on-board diagnostics (OBD) to monitor system operation.

- incorporates "self-learning" (trim) functions which allow it to adjust output functions for various operating conditions.


ON-BOARD DIAGNOSTICS
In the event of a system malfunction, circuit information is stored in the internal memory of the electronic control unit. Intermittent failures are stored with a record of the failure frequency.

The electronic control unit gives priority to those items which cause the vehicle to exceed exhaust emission standards. In addition to being stored in memory, an emissions-related failure causes the "Check Engine" light to illuminate on the instrument cluster.

ADAPTIVE CONTROL
The electronic control unit has adaptive idle speed, throttle position, and air/fuel mixture capabilities. The control unit continuously compares the programmed data, for idle control and air fuel mixture, with the input values.

If a deviation occurs, the new input values are superimposed and stored in the programmed data map. As a result, new output signals are sent to the idle control valve, and or to the injectors. This allows the electronic control unit to correct the idle speed, or injector pulse width for break-in wear or slight air leaks which might occur in the systems.

If power is interrupted to the control unit, new adaptation takes place within several minutes of engine operation.