Signs and Symptoms of Bad Spark Plug Wires
Petrol engine cars do not need servicing as often as diesel cars but nevertheless petrol cars do need to be serviced at least once per annum. Ideally a car owner should stick to the manufacturer's recommended service periods.
If your petrol car is serviced frequently you should not experience starting problems. A poorly maintained car will give starting problems especially during the winter months when the weather is wet, cold and damp.
Damaged or old hightension leads(HT) will cause starting problems because electricity is lost to the spark plugs. Should the engine run, you may experience miss-firing on some of the cylinders. A miss-firing or badly running engine will use considerably more fuel; at a time when fuel is at a premium.
However, before putting all the blame on the HT leads, one will need to do checks to eliminate other causes. If you car is running badly, first check connections especially to the coil. The coil is easily identified as it is cylindrically shaped and has a HT lead coming from one end of the device. Take out the HT lead and clean it. On both sides of the HT lead you’ll see two smaller wires make sure these are firmly attached and the contacts are clean.
Next, with a socket set take out each spark plug numbering each HT lead so they won’t get mixed up upon reassembly. Check the condition of each HT lead and if they are getting soft or perished, replace them. Now you have the spark plug out, clean the contacts and reset the gaps. If the spark plugs are old, replace them as they lose their efficiency with time.
Now remove the distributor cap and check for damage or caking to the contacts inside. Also look for splits in the plastic. Any damage or wear, and the cap should be replaced. On older cars you will see inside the distributor a set of contact points and these should be renewed at every service. Again check for gap and caking or wear and renew if necessary.
If the fault is found to be with the HT leads, do number the old ones before renewing and leave them attached to the distributor. Take a new set and replace one HT lead with an old one and re number. Now you’ll know when you come to reassemble, which HT lead goes where and to which spark plug.
