Spark plugs are a critical component of the internal combustion engine of your vehicle. Without them, fuel would not ignite in the combustion chamber. Spark plugs transmit an electrical signal sent from the ignition coil at predetermined times to create sparks, igniting the air-fuel mixture found in the combustion chamber.
Every car model needs a specific spark plug created from unique materials and a designated spark plug gap set by a qualified mechanic during installation. Good spark plugs will help inefficient burning of fuel while failing, or bad ones may cause the car not to start at all.
Spark plugs need routine maintenance and service to ensure that your engine is strong and running. Below is a comprehensive list of common sparkplug problems, symptoms, causes, and possible ways of fixing them.
Symptoms of Bad Spark Plugs
Driving with wrong or faulty spark plugs can cause some problems to your engine. Here are some symptoms of bad spark plugs:
Hard Starts
If you are having trouble starting your car, your first thought might be an empty gas tank or a dead battery. However, bad spark plugs might the cause. Your vehicle will not move if the spark plugs don’t produce the required spark to start the combustion process.
Reduced Gas Mileage
Making more trips than usual to the gas station might indicate that your car has reduced gas mileage. An unexpected drop in your vehicle’s fuel economy might suggest that you have ruined or dirty plugs. Spark plugs that are not functioning correctly can harm your vehicle’s car mileage.
Lack of Power When Accelerating
If your car is unresponsive and the accelerator has lost its sensitivity, bad spark plugs may be the cause. A spark plug doesn’t spark effectively whenever it’s dirty or fouled, causing your car to perform sluggishly.
Rough Idling
If your spark plugs are okay, your engine should sound steady and smooth. If your spark plugs have problems, they will cause your engine to sound rough when driving. In some cases, your vehicle might also vibrate.
Engine Misfires
Faulty spark plugs may cause your engine to misfire or hesitate instead of running smoothly. When the combustion process of your car is interrupted even for a short time, your engine’s performance may suffer.
Wet Spark Plug Symptoms & Fixes
You can have wet spark plugs due to engine flooding. Flooding occurs when you try to start the engine severally without it firing up.
Symptoms of Wet Spark Plugs
Here are some of the symptoms of a wet spark plug:
- The spark plug is covered with a black and wet coating, especially the central electrode
- Sometimes the spark plug has an oily appearance
Possible Causes of Wet Spark Plugs and Fixes
Here are some other possible causes of wet spark plugs:
Injector Leaks
Wet spark plugs are not common in fuel-injected engines; however, they can occur due to several mechanical failures. One common cause is a leaking cold start injector, which might lead to a rich start-up mixture in the engine compartment, causing wet spark plugs.
Engine Flooding
Many attempts to start your vehicle without success could lead to engine flooding. Engine flooding soaks the plug, making them unable to form any sparks necessary for starting the engine. This condition often occurs during cold weather conditions where previously worn-out plugs require a higher voltage to ignite the engine.
If your engine is flooding, it is best to remove the plugs, clean them, or wait for them to dry.
Worn Out Piston Rings
If you have an older vehicle engine, a worn-out piston ring could lead to wet fouling, resulting in excess release of gasoline or oil into the engine compartment. This condition could prevent a spark from forming when making an ignition attempt.
You can clean and re-install the wet-fouled spark plugs if you want them to work effectively.
What Causes Corruption on Spark Plugs?
Several factors contribute to the failure and wearing out of spark plugs. Here are some of them:
Improper Torque
Proper installation torque is essential in the spark plug’s ability to dispel heat out of the combustion chamber and into the cylinder head. Failure to use a torque wrench during spark plug installation could lead to over or under-torquing a spark plug, causing damage to the plug and, ultimately, the engine.
It’s essential to adhere to a manufacturer’s torque specifications during spark installation. Ensure that you use a torque wrench that agrees to the torque specified on the spark plug packaging. Specifications may vary by thread diameter, seat type, and cylinder head types; therefore, be sure to account for these factors during spark plug installation.
Carbon
Carbon buildup on the tip of a spark plug can cause premature failure. This might happen due to several reasons, including a clogged air filter, dirty injectors, and many other reasons.
Overheating Damage
Overheating your vehicle’s spark plugs can lead to faster wearing out of the electrode. Pre-ignition from an inadequately timed engine and an incorrect air to fuel ratio can lead to this problem.
Oil Contamination
When oil leaks onto the spark plug, it might contaminate the tip. When this happens, it might lead to damage and additional wear of the spark plug.
What Does a Black Spark Plug Mean?
Black soot on spark plugs can tell you about the possible problems with your car. It is essential to determine how the spark plugs became black before finding out why they are black. All spark plugs can blacken at the same time or by only one or two of the set. Additionally, spark plugs can darken on one side only or the entire diameter.
A black spark plug could be due to the following:
- Valve burnout characterized by blackening on one side only. Sooting on the spark plug appears from the bottom to the side electrode.
- Wrongful selection of a spark plug’s heat rating can lead to uneven blackening, and it may damage the sparkplug.
- Late ignition characterized by even black sooting.
- The air-fuel mixture produced by the carburetor or injector is too rich.
- A clogged air filter. Ensure that you check the state of your air filter and replace it if necessary.
- Problems with the ignition system due to incorrectly set ignition angle, glitches of the ignition coil, flaws of the high-voltage wire insulation, or issues with the spark plugs. These factors can lead to a weak spark; hence, not all the fuel burns leading to black sooting on the spark plugs.
- Problems with the engine valve mechanism, such as burnout of valves or unadjusted expansion gaps. There might be incomplete combustion of the air-fuel mixture and sooting of the spark plugs when this happens.
- Breaking of fuel regulator in injection cars leading to an overpressure in the fuel rail.
Can Corroded Spark Plug Wires Cause Misfire?
It would help if you ensured that spark plug wires are firmly attached to the ignition coils and the spark plugs. Experts recommend that you remove and inspect each wire when checking for corrosion. Corrosion places a gap between wires, coils, and spark plugs, often causing the engine to miss that stroke and misfire.
How Do You Clean Corroded Spark Plug Wires?
Elements of the environment and weather can lead to rust corrosion. Rust can affect your vehicle’s exterior and attack your engine as well. If you do not attend to rust, it can damage your vehicle’s structural integrity and affect its performance as well.
If rust forms on the tip of a spark plug wire, it can cause misfiring and lead to poor performance of your car. Removing the rust can save the tip of your spark plug and help you avoid replacement costs and other expensive repairs.
You can clean corroded spark plug wires using the following steps:
- Pull the spark plug wire that has the rusted tip from your car’s spark plug or distributor. If you establish that two or more of the spark plug wires are corroded, work with one wire at a time before pulling out another spark plug wire. Remember that the spark plug wires are connected to the distributor in a specific order to allow the engine to work correctly. Connecting the spark plug wires to the wrong lead can result in poor engine operation.
- Push the spark plug wire tip out of the spark plug wire’s protective boot to access the corroded spark plug wire’s tip.
- Clean the rust on the spark plug wire’s tip using a wire brush and a solvent.
- Use hot soapy water to clean the corroded spark plug wire and wipe it dry using a clean rag.
- Use a spatula to apply a thick and even rust removing gel compound onto the corroded spark plug wire tip. Let the mixture sit for about 30 minutes to 2 hours for it to penetrate the corrosion.
- Use an abrasive pad to rub the rust-removing gel compound on the corroded spark plug wire’s tip.
- Use water to rinse the cleaned spark plug wire’s tip and ensure no traces of the rust-removing gel compound.
- Repeat steps 3 to 7 above if any rust is left on the spark plug wire’s tip.
- Reattach the spark plug wire’s protective boot to cover the spark plug wire tip. Fix the spark plug wire to your car’s engine and relink it to the spark plug.
- Use the steps above to clean any other corroded spark plug wires.
Does Changing Spark Plug Wires Improve Your Car’s Performance?
The simple answer to this is yes. Changing spark plug wires and spark plugs can improve your car’s performance. Having new spark plugs will help keep your engine at efficiency levels and peak performance.
Your car may misfire occasionally; however, if the misfires become very frequent, they may get more troublesome. Frequent misfires can lead to increased exhaust emissions, reduced power, and wasted gas. If worn-out spark plugs cause the misfire, it may lead to stalling, bucking, or slow starting of older vehicles.
New spark plugs can significantly improve cold starting. Dirty or worn-out spark plugs require a higher voltage to get a spark that’s strong enough to start a vehicle. Cranking the engine severally hoping for an eventual start might run your battery dead.
What Happens If You Don’t Change Your Spark Plugs?
Your vehicle’s spark plugs will deteriorate over time; therefore, it’s essential to replace them. Failure to replace the spark plugs might result in specific issues, including:
- Unresponsive acceleration
- Stalling
- A significant decrease in fuel economy
- Failure of the engine to run or running less smoothly
When spark plugs do not spark adequately, there is incomplete combustion of the air/fuel mixture leading to loss of engine power. In some worst-case scenarios, your vehicle’s engine might fail to run.
Additionally, if deteriorated spark plugs struggle to spark, they might affect other engine parts, which supply electricity. The risk of failure of those parts will also increase significantly.
How Often Should You Change Your Spark Plugs?
Spark plugs are durable components of your vehicle that don’t need to be replaced too often; however, experts recommend that you change them about every 30,000 to 90,000 miles. It would help if you also remembered that each car might differ when it comes to when you should replace the spark plugs.
Changing spark plugs is often a simple service and could be considered a DIY endeavor; however, you should be cautious because the location of each spark plug varies depending on the manufacturer. You might experience obstructions, including significant components or parts, which might be difficult to remove if you don’t have special tools to loosen them. If you are thinking of changing your spark plugs, ensure that you consult a professional for details or check your owner’s manual to ensure that you understand when your spark plugs need replacement.
How to Tell if a Spark Plug Is Bad By Looking at It
You can’t always tell that a spark plug is bad by simply looking at it. However, if you are experiencing engine problems, a visual inspection of the spark plugs can give you an idea of some of the apparent issues and running conditions of your engine.
If you inspect your vehicle’s spark plugs, you might find at least one of the following conditions:
- Wet spark plugs
- Normal spark plugs
- Oil deposits on your spark plugs
- Broken electrodes
- Worn electrodes
- Burned spark plugs
- Carbon fouled spark plugs
Except for the regular-looking spark plugs, all conditions above indicate that your spark plugs may be impaired. Here is how to interpret the above conditions:
- Wet spark plugs: Wet spark plugs may signify engine flooding. Flooding happens if you try to start the engine severally without it firing up.
- Oil deposits on the spark plug: Oil deposits may be caused by excessive fuel additives or oil. If the residues are found on one side of the spark plug, they could indicate upper engine wear. If the oil deposits are around the electrode, it could show lower engine wear.
- Broken electrodes: Broken electrodes may occur if you install the wrong spark plugs in your vehicle. A very long spark plug can cause extensive damage to your engine, while a short one can lead to spark plug fouling and poor gas mileage.
- Worn electrodes: Eroded and worn electrodes indicate that a spark plug is past its prime. This happens when the spark plug has been in the engine for too long and needs replacement.
- Burned spark plugs: Signs of a burned spark plug include melted electrodes, blisters on the insulator tip, or white deposits. Burned spark plugs may be due to overheating your engine, incorrect ignition timing, incorrect spark plug heat range, or a loose spark plug.
- Carbon fouled spark plugs: Carbon fouled spark plugs may indicate a weak ignition, rich air-fuel mixture, or improper heat range. Carbon deposits on spark plugs are conductive and may lead to spark plug misfires.
What Causes Spark Plugs To Go Bad Fast?
Spark plugs wear out if they become old. However, several factors, including carbon, oil contamination, and overheating damage, may make them wear out faster. It would be best to understand how spark plugs work before understanding the factors that might make them wear out.
When your car’s alternator generates electricity, it’s sent through the ignition system to the spark plug wires and individual spark plugs. The spark plugs then create electrical arcs at the electrodes. Whenever a plug fires, a minute amount of metal is removed from the electrode, shortening the electrode. More electricity is required to create the arc needed to fire the cylinder. The electrode eventually becomes so worn that it might fail to arc at all.
The above happens in a regular and properly maintained engine. Although all spark plugs eventually wear out, some factors can make them wear out faster, including:
- Carbon: Carbon buildup on a spark plug’s tip can lead to its premature failure.
- Overheating damage: Overheating your vehicle’s spark plugs can lead to faster wearing out of the spark plugs. Overheating can be due to an improper air to fuel ratio or pre-ignition from an improperly timed engine.
- Oil contamination can damage a spark plug’s tip, creating damage and additional wear.
How to Test a Sparkplug
Bad spark plugs might be the reason for a sluggish engine. Low momentum while running or slow performance in your engine may indicate possible spark plug failure. Although a mechanic can help with a complete diagnosis, here is how you can test the spark plugs yourself:
- Disconnect each spark plug wire on your engine, one at a time, while the engine is still running. If your engine drops speed or starts running rough when one wire is disconnected, then the spark plug is suitable. If you disconnect a spark plug and there is no significant change in the engine, you have found a bad spark plug.
- You can test spark plug ignition by disconnecting the spark plug wire from the spark plug. You can do this by holding the end of the spark plug wire close to a metal surface. You will hear a crackling noise or see a spark if the spark plug is suitable. The spark and crackling noise mean that the voltage is getting through the wire to the spark plug.
- Check if each of your spark plug wires produces a spark whenever the engine is cranked. If compression is good, each of your spark gas cylinders will have a spark. No spark means that you have a dead spark plug wire.
- You should hook up each link connected to your spark plugs. Links include spark plug wires, battery cable, ignition, and coil wires.
- Shake the link connections from your spark plugs and test again. Sometimes a line connection may be loose.
- Check to ensure that each spark plug’s end is clean, free of any dirt, grease, or oil deposits. You can clean the end thoroughly, and they may pass the test. If they don’t test well after cleaning, you may have to replace the spark plugs.
Why Is There Some Oil on My Spark Plug?
It’s best to understand that having some oil on your spark plug is not normal. Some oil may be on your spark plug due to the following reasons:
- A lot of oil was mixed with gasoline.
- Your top cover gasket is damaged or worn
- Piston rings are failing somehow; therefore, they can allow oil to slip past the piston and get to the spark plug. When this happens, your engine might experience difficulty in starting.
- A worn-out engine. If valve seals or stems are worn out, oil might slip past them into the cylinder and coat the spark plug.
- Oil in the mixture is too thin in viscosity. When overly light oil is used, it may slip past the piston and reach the spark plug.
What Are Some of the Undesirable Effects of Oil on a Spark Plug?
If any of your spark plugs are coated in oil, your engine may malfunction. It may malfunction in one or all of the following ways:
- Rough running and misfires
- Difficulty when starting
- Complete failure to start
If you notice some oil on your spark plugs, you should investigate the cause. Your first instinct might be to clean the spark plug; however, cleaning it will not stop more oil from accumulating if you’ve not dealt with the root problem.
When you have figured out the cause of the oil deposit on the spark plug and fixed the issue, you can clean your spark plug.
How to Test Spark Plug Resistance Cap
Resistor spark plugs prevent any form of electrical interference that may disrupt cellular phone operation, two-way radio, and car radio reception. They also prevent electrical noise from interfering with the computer’s function in the engine.
You can do a resistance test using a digital multimeter. Set the digital multimeter to Ohms Ω. Hold or attach a meter probe on each end of the cable and read the total resistance on the meter. Some experts recommend that the maximum resistance be 12,000 ohms-per-foot, while others have suggested different maximum resistances.
Check this too: How To Gap Spark Plugs
It is best to consult a tune-up manual to get the exact specifications for your spark plugs.
Spark plugs play a critical role in the internal combustion of your vehicle. Failure to maintain or replace them may result in severe engine problems. It is always best to examine them regularly to ensure that they are working as they should.