Attention! When working on the ignition system with the ignition on, care must be taken, as you can get an electric shock from the high-voltage part of the ignition system. People with pacemakers are not recommended to check and repair the ignition system. Switch off the ignition before disconnecting or connecting any element of the ignition system or tester probes.
The main malfunctions of the ignition system are caused by loose or oxidized contacts, or a short circuit to high voltage ground due to contamination, moisture, or damage to the insulation of high-voltage wires. Before drawing a conclusion about the malfunction of any element in the ignition system, check the condition of the wires or electrical circuits of the ignition system.
It is not recommended to check for a spark by holding the high voltage wire a short distance from the engine, as this can cause an electric shock or damage the ignition control unit. It is also not recommended to determine misfires by sequentially removing high-voltage wires from spark plugs. It is impossible to get a true result as a result of such a test, since the ignition system installed on later models will detect an open circuit and turn off the high-voltage wire.
Engine won't 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 starter. Connect the voltmeter probes to the battery terminals and disconnect the central high-voltage wire from the ignition distributor cover and connect it to ground. Operate the starter for no more than 10 seconds and measure the voltage at the battery. If the voltage drops below 9.5 volts while the starter is running, check the condition of the battery, starter, and charging system.
If the crankshaft rotates at normal speed when starting the engine, use a strobe light to check the high voltage part of the ignition system. If the strobe flashes when starting the engine, high voltage is being supplied to the spark plugs and the condition of the spark plugs should be checked. If the strobe does not flash, check the central high voltage wire from the ignition coil to the distributor cap, the carbon contact and the distributor rotor.
If a spark is present, check the condition and performance of the fuel system.
If the spark still does not appear, the ignition control unit may be faulty and in this case it is necessary to contact a car service station.
Misfire
Random misfires can be caused by loose contacts or open circuits in the ignition control system or ignition coil primary circuit, or damage to the high voltage wires.
Switch off the ignition and check that the contacts on the electrical connectors of the ignition system are clean and free from corrosion.
Check that the ignition coil, distributor cap and high voltage wires are clean and dry. Check the condition of the spark plug electrical wires. Then check the ignition distributor cap, carbon contact and ignition distributor rotor. You can check the spark plugs by replacing the spark plugs with new ones one by one.
Persistent misfires are most likely caused by defects in the distributor cap, ignition coil, high voltage wires, or spark plugs. A stroboscope 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 ignition distributor cover. If voltage is present on all high-voltage wires, then the spark plugs are faulty.
In the complete absence of high voltage, check the secondary winding of the ignition coil, which may be damaged.
If there are malfunctions in the ignition system that cannot be eliminated on your own, you must contact a service station.