How to identify a start-up failure
Without regular inspections and maintenance, your car will eventually break down, invariably just before an important meeting or event. Save yourself time and aggravation (and potentially a hefty repair bill) with some proactive automotive inspection and maintenance tips.
There are myriad reasons your car might not start, but most issues are preceded by telltale signs and are avoidable with regular maintenance. For example, a weak or nonexistent engine crank when turning the key could indicate a dead battery or a faulty ignition system, while a strong crank but failure to start could indicate a problem with the fuel injection or electrical systems, or simply a lack of fuel. This article will focus on problems with old or damaged spark plugs, and will teach you how to inspect, diagnose problems with, and replace your spark plugs.
What do spark plugs do?
In simple terms, your vehicle operates by injecting a precise mixture of petrol and oxygen into a series of cylinders. This mixture is highly compressed by the engine, and then detonated with a burst of electricity, with the resulting controlled explosion propelling pistons in a timed and coordinated pattern, providing power to your vehicle’s driving wheels. The spark plugs are responsible for providing the electrical catalyst for this reaction, and also, secondarily, for drawing heat away from the combustion cylinders.
Naturally, working under such harsh conditions takes its toll on your spark plugs and they become less and less efficient over time, eventually requiring replacement. If you don’t regularly inspect your spark plugs, deposits can build up, or the plugs themselves can become damaged, which can manifest as poor petrol mileage, engine ‘misses’, or failure of the engine to start altogether.
Inspecting and replacing your spark plugs
Be sure to allow the engine to cool for a few hours before performing spark plug maintenance. Your first step will be to locate the plugs. Spark plugs are generally located along the top or sides of your engine (depending on how many cylinders it has). Look for a series of thick, rubbery wires plugged into your engine at regular intervals. These are your plug wires.
Grasp them firmly by the boot (the base of the wire where it connects to the engine), and gently wiggle them free of the plugs. Be sure not to yank the plug wires by the wires themselves, or you could damage them. Once the wire is detached from the plug, clean the plug area with a soft, clean rag, then use a plug attachment and socket wrench to remove the plug, turning it counter-clockwise. Inspect the gap at the head of the plug.
Light or tan deposits are typically normal, but cracks or heavy black deposits generally indicate that it’s time to replace your spark plugs. Consult your owner’s manual to ensure you get the correct replacements for your vehicle. While shopping for replacement plugs, pick up a spark plug gap checker, and ensure your replacement plugs have the appropriate size gap (information also found in your owner’s manual). Be sure to replace each plug one at a time, as the plug wires are not interchangeable. The engine sends electricity to each plug in a sequence, and mixing up the wires is an easy way to damage your engine with incorrectly timed cylinder firings.