Contents: The engine does not start ↡ Misfires ↡
Warning! When working on the ignition system with the ignition on, be careful as you may receive an electric shock from the high-voltage part of the ignition system. People with pacemakers are not recommended to check or repair the ignition system. Turn off the ignition before disconnecting or connecting any component of the ignition system or the test leads of the measuring device.
The main faults of the ignition system are caused by loose or oxidized contacts, or short circuit to ground of high voltage due to contamination, moisture or damage to the insulation of high voltage wires. Before concluding that any element in the ignition system is faulty, check the condition of the wires or electrical circuits of the ignition system.
It is not recommended to check for spark by holding the high-voltage wire a short distance from the engine, as this can cause electric shock or damage the ignition control unit. It is also not recommended to determine misfires by successively removing the high-voltage wires from the spark plugs. This test does not provide a true result, as the ignition system installed on later models will detect a break in the circuit and disconnect the high-voltage wire.
The engine does not start
If the engine crankshaft does not turn or turns very slowly when starting the engine, check the condition and charge of the battery and the starter. Connect the voltmeter probes to the battery terminals and disconnect the central high-voltage wire from the distributor cap and connect it to ground. Turn on the starter for no more than 10 seconds and measure the voltage on the battery. If the voltage becomes less than 9.5 V when the starter is running, check the condition of the battery, starter and charging system.
If the crankshaft rotates at normal speed when the engine is started, using a stroboscope, check the high-voltage part of the ignition system. If the stroboscope flashes when the engine is started, then high voltage is supplied to the spark plugs and it is necessary to check the condition of the spark plugs. If the stroboscope does not flash, check the central high-voltage wire running from the ignition coil to the distributor cap, the carbon contact and the distributor rotor.
If a spark is present, check the condition and functionality of the fuel system.
If the spark still does not appear, the ignition control unit may be faulty, in which case you should contact a car service station.
Misfires
Random misfires can be caused by loose connections or open circuits in the ignition control system or in the ignition coil primary winding circuit, or damaged high-voltage wires.
Turn off the ignition and check that the contacts on the electrical connectors of the ignition system are clean and free of corrosion.
Check that the ignition coil, distributor cap and high-tension wires are clean and dry. Check the condition of the spark plug wires. Then check the distributor cap, carbon contact and distributor rotor. Spark plugs can be checked by replacing them one by one with new ones.
Constant misfires are most likely caused by defects in the distributor cap, ignition coil, high-voltage wires, or spark plugs. A strobe light can be used to check the high-voltage supply to the spark plugs.
The absence of voltage on only one high-voltage wire indicates damage to this wire or the distributor cap. If voltage is present on all high-voltage wires, then the spark plugs are faulty.
If there is no high voltage at all, check the secondary winding of the ignition coil, which may be damaged.
If there are any faults in the ignition system that cannot be fixed independently, you must contact a service station.