Spark plugs are one of the most crucial components under your car’s hood, yet they are often overlooked until serious issues arise. These small engine parts have a huge impact on performance, fuel efficiency, and the health of your engine. Over time, spark plugs wear out and should be replaced. In this in-depth blog post, we’ll dig into spark plugs’ vital role, signs they need changing, their benefits, types, and best practices for maintenance. Read on to uncover key truths about spark plugs and why diligent replacement is so important.
What Exactly Do Spark Plugs Do?
Before exploring why they need regular changing, let’s demystify what spark plugs actually do. Spark plugs have one primary purpose – igniting the compressed air/fuel mixture within the engine’s cylinders to generate power. By creating a precise electric spark to ignite the gases at exactly the right moment, the controlled explosion of combustion can occur.
Spark plugs have an insulated central electrode that is connected to the ignition coil. Surrounding this is a grounded outer electrode. As current passes from the coil to the plug, voltage builds up until it overcomes the air gap between the two electrodes. When the voltage exceeds the gap’s resistance, the electric current arcs across, creating a high-temperature spark. Timing this spark is critical so it combusts the mixture when the piston reaches the optimal point in its compression stroke. Well-functioning spark plugs ensure this ignition process occurs properly thousands of times per minute.
Without sparking plugs supplying these properly-timed sparks, the internal combustion engine simply wouldn’t work. Their role is fundamental to generating power. Understanding this role highlights why keeping your plugs in good health through regular replacement is so important.
Warning Signs Your Spark Plugs Need Replacement
Like any engine component, spark plugs gradually wear out and decline in performance over time and accumulated miles. It’s impossible to visually assess if they are still sparking correctly while the engine is running. Drivers tend to wait until spark plug issues result in noticeable symptoms before considering changing them. Here are some common signs that warn of failing, worn spark plugs that require a swap:
a. Difficult Starting
One symptom of deteriorated spark plugs is taking longer to turn over and fire up the engine. When the plugs can no longer produce a strong spark, they struggle to ignite the compressed air/fuel mixture efficiently. This results in cranking and cranking the starter without the engine starting up. The sparks simply lack the potency to successfully ignite the mixture.
b. Rough Idling
Worn out spark plugs also begin to misfire randomly as they age. This causes roughness or jitteriness in the engine idle as some cylinders fire properly while others misfire. A smooth idle requires every cylinder to fire correctly in the proper sequence. Weak sparks cause occasional misfires that disrupt an even idle.
c. Loss of Power
As spark plugs continue to misfire, power loss becomes more noticeable, especially under heavy acceleration. You may experience hesitations, lackluster response, and an inability to accelerate at higher speeds. Depleting sparks fail to combust the air/fuel mix as efficiently, robbing the engine of power and performance.
d. Reduced Fuel Economy
Another downside of faulty spark plugs is reduced miles per gallon. When the air/fuel mixture fails to ignite properly, unburned fuel gets expelled from the exhaust. This wasted fuel lowers your overall fuel economy. Efficient combustion requires strong, clean sparks from high-functioning plugs.
e. Check Engine Light
Automobiles’ onboard computers are constantly monitoring engine performance. Sensors detect misfires caused by deteriorated spark plugs. The computer may illuminate the check engine light and store diagnostic trouble codes pointing to issues in particular cylinders. This is the surest indicator of spark plug problems.
f. Routine Replacement Intervals
Most owner’s manuals recommend replacing spark plugs every 30,000 to 100,000 miles depending on vehicle type. Shorter intervals apply to high-performance engines. Periodically swapping in fresh plugs ensures you avoid the problems above and maximize performance. Don’t wait for failure warning signs. Be proactive with preventative replacement.
Benefits of Fresh Spark Plugs
Installing a new set of properly gapped spark plugs has multiple advantages:
a. Smoother Starts
With strong sparks, the plugs can easily ignite the compressed mixture for quick, reliable start-ups. No more extended cranking in the mornings before the engine catches and fires up.
b. Improved Driving Performance
Replacing worn plugs restores acceleration and power by ensuring robust sparks inside the cylinders. Eliminating misfires and hesitations results in peppy, responsive performance.
c. Enhanced Fuel Efficiency
Complete combustion requires potent sparks from healthy plugs. Optimal firing equals maximum mpg. Efficiency can jump 2-3 mpg or more after a spark plug change.
d. Lower Emissions
Misfires waste fuel that would otherwise be combusted if fired correctly. Unburned fuel gets expelled as pollution out the tailpipe. Changing fouled or worn plugs reduces hydrocarbon emissions.
e. Engine Longevity
Timely spark plug replacement prevents minor misfires from cascading into eventual engine failure. Maintaining these small but critical components enhances longevity.
f. Restored Performance
Even fairly new vehicles can suffer performance declines due to factory-installed plugs fouling prematurely. Fresh plugs bring them back to like-new condition.
Types of Spark Plugs
While all plugs serve the same purpose, several designs and materials exist:
The most affordable option are basic copper spark plugs. These tend to have a short service life – as little as 10,000-20,000 miles. They require frequent changing but sufficiently fire most standard engines.
These ultra-durable plugs offer extremely long lifespans upwards of 100,000 miles. Their fine-wire center electrodes are encased in an iridium alloy. Ideal for today’s more demanding engines.
Platinum-tipped center electrodes resist oxidation and erosion. This makes them very long-lasting plugs. Expect 60,000 to 80,000 miles of reliable operation.
d. Double Platinum
For doubled longevity, some plugs feature platinum pads on both the side and center electrodes. This reduces wear on both firing surfaces for extended durability.
Spark Plug Replacement Tips
When installing fresh plugs, keep these essential tips in mind:
- Confirm exact plug type your engine requires before purchasing
- Use a torque wrench to tighten plugs to the proper torque specs
- Ensure sealing washers are in good condition to prevent oil leaks
- Check for leaks or coolant corrosion around old plugs prior to fitting new ones
- Replace only one plug at a time to avoid mixing up cylinder locations
- Take care not to drop objects into open plug holes as this can cause internal engine damage
- Confirm ignition coil packs seat firmly over each plug for solid electrical contact
Proper spark plug maintenance improves engine operation, extends component life, optimizes fuel efficiency, and prevents avoidable breakdowns. Understand the symptoms of failing plugs and be diligent with routine replacement intervals. Equipping your engine with fresh, high-quality plugs ensures peak performance mile after mile. Consistently changing worn spark plugs is one of the most economical and rewarding maintenance investments you can make for your vehicle.