General information and warnings

The ignition system is based on supplying low voltage from the battery to the ignition coil, where it is converted to high voltage. The high voltage is strong enough to spark through the gap of the spark plug many times per second in the cylinders. Low voltage circuit (or primary) consists of a battery, a wire to the ignition switch, a wire from the ignition switch to the low voltage winding of the coil, as well as to the terminals of the electronic units, and a wire from the low voltage winding of the coil to the terminal on the electronic module. High voltage circuit (secondary) consists of high voltage winding coil, high voltage wire (VN) from the ignition coil to the ignition distributor cap (if applicable), rotating lever (if applicable), HV wires to the spark plugs and the spark plugs themselves.

HEI system (high energy ignition) - 1.4 l engine

The least complex system, with a contactless ignition distributor and electronic booster/switch module, in addition to the ignition coil and spark plugs.

The ignition timing is carried out by the ignition distributor mechanically and by vacuum.

Multec MSTS Microprocessor Timing Control System - Single Point Fuel Injection Engines

The system controls ignition and fuel injection and contains an ignition distributor based on "hall sensor" (for engines 1.4 and 1.6 l) or crankshaft position/speed sensor (for 1.8L engine), manifold pressure sensor, coolant temperature sensor. throttle position sensor, exhaust oxygen sensor and Multec ECU in addition to the ignition coil, electronic module and spark plugs.


The electrical pulse required to turn off the low voltage circuit is generated by a sensor in the ignition distributor or by the crankshaft position/speed sensor.

Information about the engine load is fed to the Multec control unit through a pressure sensor, which is connected to the fuel injection device using a vacuum tube. Additional information is provided by the coolant temperature sensor, throttle position sensor and exhaust oxygen sensor.

The control unit selects the optimal ignition timing based on the information received from the sensors.

Multec MSTS Microprocessor Timing Control System - Multec Multiport Fuel Injection Engines

This system is the same as previously described for engines with single point fuel injection, but has the following differences.

On 1.6 liter engines, the DIS module is used (direct ignition system) instead of the distributor and ignition coil. The DIS module is connected to the camshaft housing where the ignition distributor would normally be, and consists of two ignition coils and an electronic control module housed in a molded case. Each coil is designed to supply high voltage to two spark plugs - one ignition timing corresponds to the compression stroke and the other to the exhaust stroke. The advantages of such a system are that it has no moving parts and requires no maintenance.

Bosch Motronic M1.5.2 - 2.0L single cam engines

It controls the ignition and fuel injection systems.

The Motronic ECU receives information from the crankshaft position/speed sensor, air mass meter, coolant temperature sensor, throttle position sensor, exhaust air temperature sensor, and exhaust oxygen sensor.


The electrical pulse is generated by the crankshaft position/speed sensor.

The ignition distributor has a rotating cam, used to supply high voltage current to the candles.

The control unit selects the optimal ignition timing based on information received from the sensors.

Bosch Motronic M2.5 system - engine with two camshafts

It is similar to the Motronic M1.5.2 system and has the following differences.

In addition to the crankshaft position / speed sensor, it has an ignition distributor with a Hall sensor. The electrical impulse required to turn off the low voltage circuit is generated by the crankshaft position/speed sensor. In addition, the electronic control module receives information from a knock sensor mounted on the cylinder block (chapter 4), which registers detonation (or pre-ignition) at the moment of its occurrence, allowing the module to delay the moment of ignition, thus preventing engine damage.

Warnings: See the instructions to be followed when working with models equipped with an electronic control unit, earlier in chapter 4.

Warning: high voltage (VN), generated by the electronic ignition system is high voltage and in some cases can be fatal. Avoid touching wires and HV equipment to avoid electric shock. Do not touch the HV wires, the ignition distributor or the ignition coil while the engine is running. Use well-insulated tools when working on live HV wires. Persons with implanted cardiac pacemakers SHOULD NOT work with ignition circuits, their elements and control equipment.