7 signs of a faulty ignition system:
- Engine fails to start.
After several unsuccessful attempts to start a car with a discharged battery, spark plugs can be flooded with petrol. If this happens, they’ll need to be replaced.
- Unstable idle.
This may be caused by mechanically damaged ignition cables and a short circuit in the coil winding.
- Engine runs rough on acceleration.
The malfunction may be caused by water getting on the coils, spark plugs, or ignition cables.
- Engine overheating.
This may be caused by worn spark plugs. Replace them according to the car manufacturer’s recommended maintenance schedule.
- Popping sounds in the exhaust manifold or silencer.
This occurs due to incorrect ignition timing adjustment, or use of spark plugs with the wrong heat rating.
- Increased fuel consumption.
Possible causes are damaged or loose ignition cables.
- Electrical equipment not working properly.
This may occur if the ignition switch malfunctions as a result of terminal burnout, improper use, or an attempted theft of your car.
- Remove and inspect the spark plugs and ignition coils.
They should not have any cracks or traces of carbon deposits. The gap between the side and centre electrodes of the spark plugs should be within tolerance.
- Measure the resistance of the spark plugs using a multimeter.
Attach one of the probes of the device to the thread, and the other to the centre electrode. If the resistance is over 6 kOhm, the components have to be replaced.
- Remove and inspect the distributor cap.
Make sure that the contact brush fits snugly against the surface of the rotor, and there are no cracks or thermal damage.
- Check the voltage of the fully charged battery.
If it measures below 9.5 V, the battery needs to be replaced.
- Run the engine in darkness and look under the bonnet.
If you see sparks coming from the ignition cables, that means their insulation is damaged.