Bosch LE2-Jetronic system A roller type electric pump located in the fuel tank pumps fuel through the filter to the injectors via a fuel distribution rail. The electronic control unit (ECU) which is triggered by the ignition circuit sends impulses to the injectors which operate simultaneously and inject fuel in the vicinity of the inlet valves. The electronic control unit is provided with sensors to determine engine temperature, speed and load, and the quantity of air entering the engine. This information is computed to determine the period of injection.

For cold starting, additional fuel is provided and, to compensate for this, additional air is provided by a supplementary air device.

Bosch LU2-Jetronic system The principle of operation of the LU2-Jetronic system is similar to that described above for the LE2-Jetronic system, the only significant difference is that the LU2-Jetronic system incorporates an oxygen sensor in the exhaust system. This enables the ECU to carry out fine fuel mixture adjustment, to allow the use of a catalytic converter.

Bosch Motronic M1.3 system The Bosch Motronic fuel injection system is designed to meet stringent emission control legislation whilst still providing excellent engine performance and fuel economy. The system is under the overall control of the Motronic M1.3 engine management system, which also controls the ignition timing.

The principle of operation of the system is similar to that described above for the LE2-Jetronic system, noting the following differences.

a) A double-barrel throttle housing is used with two throttle valves operating simultaneously.

b) An oxygen sensor Is fitted to the exhaust system which allows fine mixture adjustment to enable the use of a catalytic converter.

c) A TDC sensor is used to provide the ECU with information on crankshaft speed and position.