What Causes No Spark to the Spark Plug?

What Causes No Spark to the Spark Plug?

The glow plug is the single most important element of an engine. Its main role is to light an oxygen-fuel combination in the interior of the vehicle to start combustion of oil and gas to propel the car. However, there are times that the plug fails to deliver a spark, leading to engine malfunction. This guide will delve into the causes of ‘no spark’ to the spark plug, helping you understand the problem and potentially diagnose your vehicle’s issues.

No Spark From Distributor To Plugs

One of the primary causes of spark problems is the distro. It is a key element of the electrical ignition control unit that directs electrical currents from the coil to the candles in a specific ignition order. Problems such as a faulty starting point coil, worn cap or rotor, broken plug leads, or a faulty electrical ignition unit can impede the flow of power to the spark plugs, resulting in a lack of spark.Understanding and addressing these potential issues can help in restoring the normal functioning of the spark plug and the overall engine performance. [1]

No Spark From Distributor To Plugs

6 Potential Causes

Dirty or Rusted Manifold Cover

The seventh potential cause of ‘no spark’ to the spark plug is that the manifold cover may be contaminated or rusted. The manifold cover job is to cover and protect the distributor’s internal parts while also acting as a hub for spark plug wires. Over time, dirt, dust, and engine grime can accumulate on the cap, or metal parts within the cover can become corroded. This can result in poor conductivity, preventing the distributor from properly directing high-voltage electrical currents to the glow plugs in the right sequence. Regular inspection and cleaning of the distributor cap can help prevent this issue. However, if the corrosion is too severe, changing the distributor lid may be necessary.

6 Potential Causes

Defective Sensor for the Crankshaft Angle

The main crankshaft encoder performs an essential role in the fuel injection function. This component is used to monitor the location and velocity of the crankshaft and sends this information to the ECU. This information is utilized by the control unit to control the timing of the valve timing and fuel delivery. If the engine’s crankshaft encoder becomes damaged or faulty, it may provide inaccurate data or no signal at all. Lack of precise feedback can lead to the ignition torque being controlled incorrectly by the ECU, preventing the spark plugs from lighting at the right time or not lighting at all. Problems with the crankshaft encoder may result in engine misfiring, sputtering, or inability to start. Regular inspection and maintenance of the crankshaft encoder is therefore essential for optimal motor operation. If these problems occur, you should consider checking or replacing this sensor.

Defective Sensor for the Crankshaft Angle

Problem with the engine management unit

The ignition control module (ICM) is another important component that can be responsible for a lack of spark in the glow plugs. The control module is essentially the heart of the ignition circuit, controlling the activation of the coil and the candle ignition order. It works in conjunction with the vehicle’s ECU to manage the precise timing required for efficient combustion. If the ICM malfunctions or fails, it can disrupt this controlled sequence, preventing the spark plugs from sparking at the correct time or not sparking at all. Symptoms of a failing ICM can range from low fuel savings and lower power output to engine misfires and the vehicle not starting at all. It is crucial to address such problems immediately to prevent subsequent injury to the engine. If the ICM is suspected to be at fault, it should be tested and, if necessary, replaced to restore the normal functioning of the engine.

Problem with the engine management unit

Problems With the Inductor Coil Within the Timing Distributor

The intake coil within the distro plays a key role in the lighting process. It generates a voltage waveform that the ignition control module (ICM) uses to start the plug, causing the spark plugs to spark. If the pickup coil itself becomes faulty or damaged, it can result in a ‘no spark’ situation with the spark plugs. Issues could range from the pickup coil being out of alignment, a broken pickup coil wire, or deterioration due to heat and vibration over time. As such, the signal to the ICM would be disrupted, leading to an interruption in the ignition process. Symptoms of a faulty pickup coil can include hard starting, intermittent misfires, or the engine not starting at all. To resolve such issues, it is necessary to inspect the pickup coil and if found defective, it should be replaced promptly to restore the engine’s normal function.

Poor plug coil

The ignition core plays a pivotal role in a car’s fuel ignition engine by converting negative voltage energy from the car’s accumulator into the positive voltage needed by the plugs to fire the fuel-air mix in the engine’s cylinders. Essentially, it acts as a high-voltage transformer. A failing or damaged ignition coil can lead to a no spark situation because it can’t provide the necessary electrical current to the spark plugs. Symptoms of a bad ignition coil can include engine misfires, power loss, reduced fuel efficiency, and difficulty starting the vehicle. If an ignition coil is suspected to be faulty, it is recommended to have it tested by a professional and replaced if needed to restore the engine’s normal operation.

Problems With the Inductor Coil Within the Timing Distributor

A Faulty Ignition Switch

The ignition switch is a critical part of the vehicle’s ignition system, acting as the gateway for the flow of electricity from the battery to the rest of the ignition system, including the spark plugs. It essentially functions as an on-off switch, initiating the ignition system when the key is turned. If the ignition switch becomes faulty or fails, it could interrupt the flow of electricity, leading to a ‘no spark’ issue with the spark plugs. Symptoms of a faulty ignition switch can range from the vehicle stalling, difficulty in starting the vehicle, or the vehicle not starting at all. Other signs might include flickering dashboard lights and a hot ignition switch or key. It is crucial to address these issues promptly to prevent potential safety risks and further damage to the ignition system. If a faulty ignition switch is suspected, it is recommended to seek professional help for testing and, if necessary, replacing the ignition switch to restore the vehicle’s normal operation. [1], [2]


What are common causes of no spark?

There are several underlying issues that could lead to a ‘no spark’ situation in spark plugs. Among the most common causes are:

  1. Corroded Distributor Cap: Over time, the metal contacts inside the cap can corrode, leading to poor conductivity. This prevents the distributor from directing high-voltage electrical currents to the spark plugs in the correct order.
  2. Faulty Crankshaft Position Sensor: This sensor monitors the crankshaft’s position and speed, sending this data to the engine control unit (ECU). If it malfunctions, it could produce inaccurate data, leading to the mismanagement of ignition timing.
  3. Malfunctioning Ignition Control Module (ICM): The ICM controls the ignition coil’s activation and the firing sequence of the spark plugs. If the ICM fails, it can disrupt this sequence, preventing the spark plugs from sparking at the correct time.
  4. Issues with the Pickup Coil: Inside the distributor, the pickup coil generates a voltage signal that the ICM uses to trigger the ignition coil. If the pickup coil is faulty, it can disrupt this signal, leading to an interruption in the ignition process.
  5. Bad Ignition Coil: The ignition coil converts low-voltage power into the high-voltage current required for the spark plugs. A failing ignition coil can’t provide the necessary electrical current, leading to a ‘no spark’ situation.
  6. Faulty Ignition Switch: The ignition switch acts as the gateway for the flow of electricity from the battery to the ignition system. If it fails, it can interrupt this flow, preventing spark plugs from igniting.

By understanding these common causes, you can better diagnose and address ‘no spark’ situations in your vehicle’s ignition system.

What happens if a spark plug doesn’t spark?

If a spark plug fails to spark, the crucial combustion process needed for the engine’s operation cannot take place. This is because the primary function of a spark plug is to ignite the meticulously balanced air-fuel mixture within the engine’s cylinders. Without this essential spark, the combustion simply cannot occur, resulting in potential problems. The engine may struggle to start or run sluggishly, adversely affecting its overall performance. This can manifest in various noticeable symptoms, such as difficulty starting the vehicle, decreased fuel efficiency, frequent engine misfires, rough idling, and reduced power while accelerating. As time progresses, these issues can exacerbate and potentially cause severe damage to the engine, leading to the need for costly repairs. Consequently, it is imperative to promptly address any ‘no spark’ complications to prevent further complications or detrimental consequences. By taking swift action, you can safeguard the engine’s longevity and avoid unnecessary expenses in the long run.

What if my ignition coil has power but no spark?

If the ignition coil has power but there’s no spark, it may suggest the coil is unable to convert the low-voltage power into the high-voltage current necessary for the spark plugs. It could be due to a faulty ignition coil, a problem with the ignition control module (ICM), or issues with the spark plug wires. It’s also possible that the ignition coil may be failing due to wear and tear, overheating, or internal damage. To pinpoint the problem, it’s advisable to conduct a thorough inspection of the ignition system, including testing the ignition coil with a multimeter, checking the condition of the spark plug wires, and examining the ICM for any malfunctions. If any of these components are found to be faulty, they should be replaced promptly to restore the proper functioning of the ignition system.

What causes plugs not to burn?

There could be several reasons why the spark plugs are not igniting, or ‘burning’, as it’s sometimes referred to. Here are some common causes:

  1. Faulty or Worn-out Spark Plugs: Spark plugs can become worn out or damaged over time, which can negatively affect their ability to ignite the fuel-air mixture in the engine cylinders.
  2. Incorrect Spark Plug Gap: If the spark plug gap – the distance between the center and side electrodes – is not set correctly, it could affect the spark plug’s ability to produce a spark.
  3. Poor Quality Fuel: The use of poor quality or incorrect type of fuel can lead to incomplete combustion, leaving residue on the spark plugs and reducing their capacity to generate a spark.
  4. Bad Ignition Wires: The ignition wires carry the high voltage current from the ignition coil to the spark plugs. If they are damaged or corroded, they could prevent the necessary current from reaching the spark plugs.
  5. Engine Timing Issues: If the engine timing is off, it could lead to the spark plugs firing at the wrong time, which could prevent combustion from occurring.

If the spark plugs are not burning, it’s important to inspect the ignition system thoroughly to identify the cause, and make the necessary repairs or replacements to restore the engine’s proper operation.

Can timing cause no spark?

Yes, incorrect engine timing can indeed result in a ‘no spark’ situation. The engine’s timing, which determines at what point in the piston’s cycle the spark plug should fire, plays a crucial role in the combustion process. If the timing is off, the spark plug may fire at the wrong time or not at all, disrupting the combustion sequence and leading to engine issues.

Misaligned timing can be caused by various factors, such as a faulty timing belt or chain, incorrect installation of these components, or issues with the control module that manages the timing. These factors can throw off the precise synchronization required for optimal engine performance.

If you suspect that incorrect timing is causing your spark plugs not to fire, it’s essential to have it checked by a professional mechanic. They have the expertise and specialized equipment to diagnose and rectify timing-related problems. By accurately assessing and adjusting the engine’s timing if necessary, they can resolve the ‘no spark’ issue and restore normal engine operation.

Addressing engine timing issues promptly not only ensures proper combustion but also helps prevent potential damage to other engine components. So, if you notice any signs of misfiring spark plugs or suspect timing-related problems, it’s advisable to seek professional assistance for a thorough inspection and timely resolution.

What tells the spark plug to fire?

The act of a spark plug firing is a meticulously orchestrated sequence of events within the ignition system of a vehicle. It begins with the ignition coil, a crucial component that converts the low-voltage electricity from the battery into a high-voltage current. This high-voltage current is precisely what’s needed to create a powerful spark. From there, the current travels through the ignition wires, making its way to the spark plug.

But there’s more to this process than meets the eye. The Engine Control Module (ECM) or Ignition Control Module (ICM) comes into play, meticulously controlling the timing of each spark plug firing. It relies on data from a network of sensors, constantly monitoring and analyzing the engine’s conditions. By considering factors like engine temperature, air-fuel mixture, and throttle position, the ECM or ICM determines the optimal moment for each spark plug to ignite.

This precise timing is crucial for efficient combustion within each cylinder. When the spark plug fires at just the right moment, it ignites the air-fuel mixture, resulting in a powerful explosion that drives the piston down and powers the vehicle. However, if the timing is disrupted for any reason, it can lead to issues with the engine’s performance.

So, the next time you start your vehicle and hear that familiar spark plug firing, remember the intricate dance of components and the meticulous timing that goes into making it happen. It’s a testament to the engineering marvel that is the ignition system, ensuring your engine runs smoothly and efficiently.

What controls the firing of spark plugs?

The Engine Control Module (ECM) or Ignition Control Module (ICM) primarily governs the firing of the spark plugs in a vehicle. The ECM/ICM receives data from various sensors in the engine, such as the Crankshaft Position sensor and Camshaft Position sensor, and uses this information to precisely determine the exact moment each spark plug should fire for optimal combustion. In addition to timing, the ECM/ICM also regulates the duration and strength of the spark, further enhancing combustion efficiency. However, it’s worth noting that other components of the ignition system, such as the ignition coil and ignition wires, play crucial roles in delivering the high-voltage current necessary for the spark plug to fire. Therefore, the successful firing of a spark plug is a result of a collaborative process involving numerous components, all precisely controlled and coordinated by the ECM/ICM.

How do I know if my spark plugs are getting power?

To determine if your spark plugs are receiving power, you can perform a spark test. For this, you’ll need a spark tester – a tool specifically designed to test the ignition system – and safety gloves to protect yourself from potential shocks. Here are the steps to perform a spark test:

  1. Disconnect a Spark Plug Wire: Start by carefully disconnecting a spark plug wire from one of your spark plugs. Be sure to grab the wire by the boot (the thick insulation part), not the wire itself.
  2. Attach the Spark Tester: Connect the spark tester to the disconnected spark plug wire. Some spark testers need to be grounded to the engine, so follow the instructions provided with your spark tester.
  3. Crank the Engine: Have someone crank the engine while you watch the tester. If a strong, blue spark jumps across the tester gap, your spark plug is receiving power.
  4. Test All Spark Plug Wires: Repeat this process for each of your spark plug wires. If any of them doesn’t generate a spark, there’s likely an issue with that wire, the spark plug connected to it, or the ignition system as a whole.

Remember, this is a high-voltage test and should be done with caution. If you’re uncomfortable performing this test yourself, it’s best to have it done by a professional mechanic.

Useful Video: NO SPARK! How Do I Know If My Coil / Ignition Module Is Faulty? (DAY 23)


In summary, the functioning of spark plugs is not only integral but also crucial to a vehicle’s ignition system. These small yet mighty components play a significant role in ensuring smooth engine operation and optimal combustion.

There are several factors that can contribute to a ‘no spark’ situation. One common cause is worn-out or incorrectly gapped spark plugs, which can hinder the ignition process. Additionally, the quality of fuel used can also impact the spark plug performance. Poor quality fuel may lead to deposits or fouling on the spark plugs, affecting their ability to generate sparks effectively.

Furthermore, the condition of ignition wires is another important factor to consider. Faulty or damaged wires can disrupt the flow of electricity, resulting in a weak or nonexistent spark. It is crucial to inspect and replace any worn or damaged ignition wires to maintain proper ignition.

Engine timing is yet another factor that can affect the firing of spark plugs. Incorrect timing can lead to misfires or inefficient combustion, which can have a negative impact on the vehicle’s performance and fuel efficiency. The Engine Control Module (ECM) or Ignition Control Module (ICM) plays a vital role in governing the timing of spark plug firing. These modules utilize data from various engine sensors to ensure precise timing and optimal combustion.

Diagnosing problems with spark plugs requires thorough inspection and testing. One commonly used method is a spark test, which involves examining the spark plug for a strong, consistent spark. However, it is important to exercise caution during this test due to the high voltages involved.

While DIY troubleshooting can be helpful, for precise diagnosis and repairs, it is often recommended to consult with a professional mechanic. They have the expertise and specialized tools to accurately diagnose spark plug issues and provide the necessary repairs or replacements.


  1. https://www.briggsandstratton.ca/na/en_ca/support/faqs/browse/ignition-system-theory-and-testing.html
  2. https://www.repairsmith.com/blog/no-spark-from-distributor-to-plugs/