Q: How to replace spark plug wires in an electronic ignition system?
A: The carbon-impregnated cord conductor which has 8mm silicone rubber insulation and is used in Spark Plug wires in electronic ignition systems provides excellent insulation for high voltage in electronic ignition systems and can withstand high temperature. This creates tight waterproof seals between the boots of the spark plugs and the wires. When purchasing new spark plug wires, an engine-specific wire set is highly recommended as they are pre-cut with boots attached to them. Though these cables may be soft, they can handle a lot of heat and voltage, though they are liable to scuffing and cutting. One should be careful not to run or damage it by keeping it away from sharp edges. In cases of tune-ups or inspections, check all wires visually for burns, cuts or damages on their insulation while inspecting the Distributor Cap's nipples and coils' boots on these components; this must be done every time you notice a fault on it to ensure that there are no compromised ones. Besides, every 50k miles (80k km) or sixty months measure wire resistance using ohmmeter to check excessive resistance leading to misfiring problems when starting under wet conditions. To do this, disconnect each wire one at a time, place one ohmmeter lead on the side with the spark plug then another at the distributor or coil side replacing any wire that exceeds a resistance of 7k ohms per foot. Sometimes, intermittent issues can be located because water mist will actually arc ground through its arcs when secondary components fail completely. When removing & installing spark plug wires/ cables label them if possible and one after another replace them as well The boots of the spark plug wire should be removed carefully when twisting and pulling it off from the plugs instead of directly pulling out of the wire itself. For 4.5L & 4.9LI engines, disconnect spark plug cable at distributor assembly as well as at plugs then remove engine's channel plus wires from a spark plug. For 4.6L engines, disconnect spark plug cables at Ignition Control Module (ICM) assembly and plugs while removing them before getting the channel and wires of the spark plugs to be installed in reverse order.