Introduction | 3B Description | ABY Changes | Schematics | Boost Control | Diagnostics

Bosch Motronic Info

3B System Description

The Motronic ECU on the 3B engined S2 Coupe is described in this section, along with an overview of the main components assoiated with the ignition, injection, boost and emission control systems. Because all of the engine's operating parameters are controlled electronically  by the ECU firmware there are no mechanical adjustments on the 3B engine (beyond the alignment of the timing belt, camshaft chain and distributor) which can affect the running or tuning of the engine. 

Over time, the engine diagnostics link in the above sub-menu, will outline methods for testing some of the Motronic system components in the unlikely event of a problem on your S2.


3B System Specifications

Firing Sequence 1-2-4-5-3

Max Horsepower (bhp / kW)

220 / 162

Max Torque (lbft / Nm)

228 / 309
Compression Ratio 9.3 : 1
Max Charge Pressure (bar) 1.83
MAP Operating range (bar) 0 - 2.0
Max Fuel Pressure (bar) 3.0
ECU Part Number 895.907.404 BA

The figure below shows the many input and out devices that are connected to the ECU. The system inputs are shown on the left whilst the outputs are collected on the right of the figure.

Click here for better resolution image

The table below lists all the major components that comprise the Motronic engine management system. Each item is linked to a brief description of how the component works. A reference to the wiring schematic for each component is also provided.


Last Updated 24th March 2002