• General information
• Contactless ignition system
• Precautions for use and repair of the ignition system
• Technical data of the ignition system
• Checking the ignition system and its components
• Checking and replacing the ignition coils
• Replacement of the commutator on models from 1996 to 1998
• Replace the ignition distributor on models from 1996 to 1998
The ignition system is designed to ignite the air-fuel mixture in each cylinder at a specific moment in time. In petrol engines this is achieved by an electrical spark (electrical discharge) created between the electrodes of the spark plug.
Reliable ignition operation over the entire engine operating range is essential for the catalytic converter to work efficiently.
The spark ignites a small cloud of fine fuel-air mixture, which is sufficient to initiate the combustion process.
The spark plug determines the length of the spark, which also depends on the type and construction of the ignition system and the ignition conditions.
To create a spark, the voltage between the electrodes of the spark plug must rise sharply from zero to the voltage necessary for arcing. After the spark discharge the voltage drops to the level necessary for the propagation of the spark, at which point the fuel/air mixture is ignited.
An ignition coil, which operates on the principle of an autotransformer and stores the ignition energy, is used to generate the spark energy. When current is applied to the primary winding of the ignition coil, the current energy is converted into magnetic field energy until the current flow fails. The magnetic field is thereby drastically reduced, inducing a high current in the secondary coil of the ignition coil which flows through the high-voltage conductors to a single spark plug.
Approximately 2 ms elapse between the initial ignition of the mixture and its complete combustion. The spark must therefore occur before the piston reaches TDC to ensure optimal combustion throughout the engine speed range. The ignition timing is determined by the crankshaft speed, load, engine configuration, fuel quality and the current operating conditions (starting, idling, throttle opening, etc.).
The spark plug serves to transfer the high voltage current generated in the ignition coil to the electrodes in the combustion chamber, where this current produces a spark discharge to ignite the mixture.
Non-contact ignition system
The 1996 to 1998 models had a conventional non-contact ignition system comprising ignition switch, battery, distributor and ignition coil, electronic control unit (ECU), crank angle sensor, spark plugs and leads.
The Electronic Electronic Control Unit (ECU) controls ignition timing based on input from sensors which monitor engine conditions such as engine speed, air intake, coolant temperature etc. in all operating modes. The ECM is located on the right-hand side in the engine compartment.
This non-contact ignition system comprises an inductive sensor located inside the ignition distributor, an ignition coil fixed to the intake manifold near the ignition distributor and a commutator located in the engine compartment.
On models from 1998 to 2001, the commutator and the ignition coils are made as a single unit mounted on a bracket on the intake manifold.
On models from 2001, the commutator/ignition coil assembly is mounted on each cylinder, directly on the spark plugs and does not require the use of high-voltage wires.
On models from 1998 to 2001, the non-contact ignition system comprised of a camshaft position sensor, crankshaft angle sensor, ignition coils (one coil per 2 cylinders), commutator and engine control unit (PCM). The ignition coil and the commutator are a single unit and are mounted at the front of the engine. Based on signals from the camshaft position and crankshaft angle sensors, the engine control unit identifies a cylinder and sends a control impulse to the commutator to inject a spark into the respective cylinder. Each ignition coil actually consists of 2 separate high voltage windings which supply the spark to two cylinders each (one to cylinders 1 and 4 and the other to cylinders 2 and 3). The ignition impulse is fed to the two spark plugs at once for each engine cycle, one on the compression stroke, one on the exhaust stroke - the ignition spark on the exhaust stroke has no effect on engine performance and is therefore consumed "idle". The engine control module (PCM) uses the signals from the various sensors to calculate the appropriate advance angle and ignition coil energy storage time.
On models from 2001, the non-contact ignition system comprises a camshaft position sensor, crankshaft angle sensor, ignition coil/commutator/ spark plug assembly fitted on each cylinder and the engine control module (PCM). Based on the signals from the camshaft position and crank angle sensors, the engine control unit identifies the cylinder and sends a control impulse to the appropriate ignition coil/commutator/ignition spark plug assembly, and calculates the required ignition advance angle setting and the energy storage time of the ignition coil.
Precautions for operation and repair of the ignition system
Take the following precautions when working on the ignition system:
- do not hold the ignition key in the ignition switch position for more than 10 s if the engine will not start;
- connect the tachometer according to the tachometer manual. Some tachometers may not be compatible with this ignition system;
- do not connect the ignition coil terminals to the earth;
- do not disconnect the battery terminals when the engine is running.
In the electronic ignition system, the ignition voltage is greater than 30 kV. Under unfavourable circumstances (increased humidity in the engine compartment), voltage peaks can penetrate the insulation and cause a shock when touched.
To avoid personal injury and damage to the ignition system, observe the following when working on the system
- do not touch by hand or disconnect the ignition cable when the engine is running or the engine crankshaft is turning with the starter motor;
- Do not disconnect the ignition cables or connect or disconnect any gauges until the ignition is off;
- if the engine is hotter than 80 °C (e.g. when painting the vehicle), do not start the engine immediately after heating;
- do not wash the engine while it is running;
- disconnect the battery when carrying out electrical welding work;
- Do not repair the ignition system for persons with a pacemaker.
Checking the ignition system and its components
Checking and replacing the ignition coils
Replacement of the commutator on 1996 to 1998 models
Replace the ignition distributor on models from 1996 to 1998
WARNING
Due to the high voltage generated by the ignition system, care must be taken when carrying out any work on ignition system components.
Carry out a general check of the ignition system as follows:
If the engine turns on the starter but does not start, disconnect the high-voltage cable from any spark plug and connect it to an additional, serviceable plug whose housing is securely fastened to the engine.
Depressurise the fuel system. When checking the ignition system, do not connect the fuel pump electrical connector.
Turn the crankshaft and look carefully at the inter-electrode gap of the auxiliary spark plug. There should be occasional bright blue sparks.
If sparks are present, remove and connect the high-voltage leads one by one to the spark plug. Spark formation on each high voltage wire indicates that the ignition coils are in good condition. However, the spark plugs themselves may be dirty, so unscrew and clean them or replace them with new ones.
If there is no or very erratic sparking, check the ignition coil circuits and the resistance of the ignition coil windings and the condition and resistance of each high-voltage wire.
If all tested components and circuits are OK on 1996 to 1997 models, the ignition coil may be defective and on 1998 models, the camshaft position sensor and/or crankshaft angle sensor may be defective.
Checking and replacing ignition coils
NOTES
At the time the repair manual was written, there was no information about the resistance value of the primary coil on models from 1998 to 2000 and information about checking the ignition coil/switch coils on models from 2001.
Check the resistance of the ignition coil windings on the cold engine, as the resistance will be greater on a hot engine. The windows are switched off immediately.
Check the ignition coils as follows:
Check the primary coil resistance of the ignition coil by
- switch off the ignition and disconnect the electrical connectors from each ignition coil;
Replacing the commutator on models from 1996 to 1998
NOTE
On models from 1998 onwards, the commutator is an integral part of the ignition coil assembly.
To replace the commutator on 1996 to 1998 models, proceed as follows:
Switch off the ignition and disconnect the earth cable from the battery.
Unplug the electrical connector from the commutator.
Remove the screws and remove the commutator.
Reinstall in the reverse order of removal.
Ignition distributor replacement on models from 1996 to 1998
Remove the ignition distributor on 1996 to 1998 models as follows:
Switch off the ignition and disconnect the earth lead from the battery.
Unplug the electrical connectors from the ignition distributor.
Ensure that there is a "1" at the ignition distributor cap near the first cylinder's high-voltage spark plug wire connection terminal, otherwise apply a mark.
Remove the ignition distributor cap and turn the engine crankshaft to a position where the rotor is pointing towards the "1" terminal of the first cylinder spark plug ignition lead with the first cylinder piston at TDC in the compression stroke.
