Ignition coils are crucial to a vehicle’s ignition system; their condition would surely affect the efficiency and performance of spark plugs and, as a result, the efficiency of an engine.
If the ignition coils become faulty, you would face hard starts from the engine or even difficulty running. Read on to know how the ignition coil operates. Go through this article to learn about the signs of it being defective.
What are Ignition Coils & Their Function?
When you apply a voltage of at least 12 V, you can detect that the ignition coil forms part of the ignition system. This generates the high-voltage spark necessary for igniting the air-fuel mixture. The coil draws 12 volts from the battery, then transforms it to 60,000 volts simply to deliver an energy pulse to the spark plug as per the time schedule.
In modern car engine technology, an ignition coil is fitted to each spark plug—the coil-on-plug (COP) system. This efficiently counters the traditional distributor-type systems, which do not even come close to the COP’s extraordinary timing accuracy and performance.
The car’s computer can sense engine conditions and command each coil precisely when and how hard it should fire, improving efficiency and helping to reduce emissions. Without functional ignition coils, your car will misfire, lose power, or fail to turn over.
5 Signs Your Ignition Coil Is Failing
The failed ignition coil lights up your check engine light, but that’s only the initial stage. Coil failures can bring your vehicle’s performance to a standstill. Here are five indicators you should not ignore since they give important information.
1. Engine Misfires, Especially at Idle
When the engine begins to misfire, it will reveal a troubled ignition coil. A coil not delivering enough voltage causes spark plugs to misfire, leading to engine shaking, sputtering, or jerking. This becomes almost clear when your car is idling at a red light or frequently stopping and starting.
2. Hard Starting or Failure to Start
One or more cylinders will not fire if your ignition coil is defunct. It makes starting the engine very tough, especially in cold weather. If it takes your car longer than usual to start or it cannot start at all, blame a weak ignition coil.
3. Significant Power Loss While Driving
A defective coil can generate comparatively weaker combustion, therefore decreasing engine power. Slow acceleration, poor throttle response, and power loss when climbing hills or merging onto highways would become apparent. Every day driving would also make the engine feel slow in progress.
4. Reduced Fuel Efficiency
When sufficient combustion fails because of weak sparks, fuel combustion increases. This resulted in higher fuel consumption owing to limited energy production. So, if frequent fill-ups seem to be happening more often than found before or the overall mileage per gallon has dropped, poor ignition coil quality might be affecting fuel consumption.
5. Smoke, Popping Sounds, or Backfiring
Symptoms result from fuel not getting into combustion chambers or the exhaust system, which ignites off suddenly, resulting in backfires, black billowing smoke from the tailpipe, or a distinct fuel smell. Those symptoms indicate that your car suffers from misfiring troubles that would eventually ruin your exhaust system if you were not quick to rectify them.
How Many Days Can You Drive with a Defective Ignition Coil?
However, it is not advised to drive around with a faulty ignition coil since its consequences can be truly disastrous for the engine in the long run. The engine will still function when there is a malfunctioning ignition coil; however, performance concerns will begin to develop. These include too many engine misfires, decreased fuel consumption, and potential engine stalls.
Depending on the severity of the malfunction, you will get anywhere from a few extra miles to maybe a day or two of driving before it fails. The longer you drive it, the more damage you do to the catalytic converter, spark plugs, or other engine components. Sometimes, you may add to the repair costs since the delayed repairs also affect the ignition system.
Have your ignition system checked and repaired immediately if rough idle, lack of power, or occasional engine cranking troubleshooting signs apply to you, because more damage can result from a longer delay before repair interventions.
Can You Drive with a Bad Ignition Coil?
Technically, yes, but it isn’t very careful. In an older engine with a single ignition coil, such a failure would likely mean the engine would not start. On the contrary, in the case of a modernized vehicle that boasts a coil-on-plug (COP) system, the car might start anyway if there’s only one defective coil.
Driving your automobile while its ignition coil is bad may result in engine backfires, increased fuel consumption, and poor performance. Long-term catalytic converter and spark plug damage could also occur. Issues that start small can easily multiply and become an expensive repair bill.
If you suspect your ignition coil has failed, do not use the vehicle; have it checked by a qualified mechanic. Early detection might save your engine and some dollars from your pockets when you save it early.
What’s the Lifespan of an Ignition Coil?
Normal conditions usually specify that ignition coils last according to vehicle used, but this may be affected by the types of vehicles, driving conditions, or engine maintenance activities.
The modern ignition coil was developed within a coil-on-plug (COP) arrangement, leaving behind much older coil-on-plug mechanisms without doubt about their sturdiness concerning mounting alongside several other components of so-called single-coil arrangements.
7 Top Engine Problems That Lead to Ignition Coil Damage
Ignition coils convert the battery voltage into the high voltage required to trigger fuel combustion. When they fail, you may notice instances of engine misfiring, lower fuel economy, or stalling at the most inconvenient times.
What, then, are the triggers that wear out ignition coils? These are usually the top few engine problems that lead to ignition coil failure:
1. Worn Spark Plugs or Plug Wires
The ignition coils can send a high-resistance spark. Since the spark plugs have gotten old and fouled, the ignition coils may have overheated or been damaged.
Signs: Misfires, rough idle, and lack of acceleration.
2. Oil or Coolant Leaks
Corrosion and shorting of the ignition coil happen when oil or coolant enters the spark plug wells. This commonly originates from bad valve cover gaskets or a head gasket leak.
Signs: Engine misfire, smell of oil, and check engine light.
3. Excessive Heat and Vibration
Heat and vibration are the lifeline of any engine; however, when these become excessive, primarily due to malfunctioning mounts or cooling issues, they wear out ignition coil wires and components over time.
Signs: Intermittent misfires, overheating light, and engine knocking.
4. Overvoltage from a Faulty Battery or Alternator
Faulty alternators sending sudden voltage spikes through the ignition system can damage ignition coils and other sensitive components.
Signs: Flickering of dashboard lights, battery warning light, and repeated ignition coil failures.
5. Moisture Intrusion
Water can move into the ignition system via a cracked coil housing, broken seals, or when the car is deep in water. The onset of corrosion and short circuits follows within the coil.
Signs: Engine stalling in rain, electrical shorts, and misfiring.
6. Carbon Tracking
Carbon tracking occurs whenever voltages from the ignition coil jump to ground through the cracked spark plug insulator. This can overload the ignition coil circuit and result in premature failure.
Signs: Black streaks are visible on the spark plug, engine function has become erratic, and performance has diminished.
7. Improper Spark Plug Gap
Too wide or too narrow a spark plug gap adds to the weight of the ignition coil. Too wide a gap would require the spark coil to build up that much additional voltage, which would either weaken and overheat it over time.
Signs: Hesitates, poor throttle response, and lacks power.
9 Methods Used to Prevent Ignition Coil Damage
1. Replace Spark Plugs Regularly
- Old and worn-out spark plugs build up resistance in the ignition system, causing the ignition coil to overwork and overheat.
- Follow service intervals for changing the spark plugs, as the manufacturer prescribes.
2. Fix Oil and Coolant Leaks Immediately
- Oil or coolant leaking into the spark plug wells can corrode ignition coils or create electrical shorts.
- Check the valve cover and head gaskets for leaks, replacing them if necessary.
3. Use High-Quality Ignition Components
- Cheap aftermarket coils or plugs wreck the electrical system and cause premature failure.
- Always buy OEM or high-quality aftermarket parts from reputable brands.
4. Maintain Proper Spark Plug Gap
- Wrong gaps on spark plugs give rise to excessive voltage demands across the ignition coil.
- A feeler gauge must be used to ensure that the gap conforms to the vehicle’s specifications at installation.
5. Check Battery and Charging System Health
- The battery and alternator condition is often responsible for voltage fluctuations, placing additional stresses on the ignition coil.
- Battery and alternator output should be checked periodically, especially when almost every electrical component of the vehicle seems to be acting up.
6. Avoid Engine Overheating
- Excessively high heat inside the engine would significantly accelerate the failure of the ignition coil components.
- Ensure the radiator, thermostat, and coolant level in the cooling system are functioning properly.
7. Secure Coil Packs and Electrical Connectors
- Loose connectors or coil mounts can allow for vibrations and intermittent contacts that damage internal coil windings.
- Coils must be checked routinely for tight-fitted placement and corrosion-free connectors.
8. Protect Against Moisture Intrusion
- Cracks in coil housings or worn rubber seals allow water to enter and short the coils.
- After washing the engine or driving through water, ensure the engine bay is dry and well-ventilated.
9. Address Engine Misfires Quickly
- Continuous misfires can overheat and damage ignition coils.
- Diagnose and repair misfire codes (P0300 series) as soon as they appear.
Need Ignition Coil Replacement or Car Services Help? Contact Us!
At ARMotors, we bring over 17 years of experience in premium car repair and maintenance. Located in Dubai Industrial City, Dubai, our state-of-the-art 29,000+ sq. ft. garage is equipped with 25 car lifts to handle all major automotive needs efficiently.
We specialize in servicing top car brands worldwide, ensuring expert ignition coil replacements and comprehensive car care. Trust ARMotors for reliable, professional service—your car is in expert hands.
Final Thoughts
Ignition coils may be small, but their role in your engine’s performance is massive. From starting your car to maintaining fuel efficiency, a healthy ignition system is non-negotiable. Understanding the early signs of coil failure and its causes will save you from costly repairs.
Monitor any maintenance of your spark plugs, identify leaks, and ensure engine components are serving their purposes ably. Trust us for professional diagnostics and reliable repairs—where expertise meets precision in every service.
