Main Reasons for Misfiring
Your car engine misfires due to several reasons. At times, it can be related to fuel, faulty mechanical components, and cylinders. Let’s get a detailed understanding of it:
Spark plug problems (Petrol engines)
A spark plug is one of the vital components of a petrol car engine. It continuously heats and cools down during operations, wearing itself out in the long run. Additionally, any damage to the plug can lead to a disruptive electricity flow between the plugs. It results in ignition issues.
Ignition coil issues
The ignition coil generates the required voltage to spark the plugs and get the car moving. If this coil has worn off and is producing inconsistent voltage, there is a potential chance of a misfiring engine. This problem is more likely to occur at high engine RPMs.
Fuel problems
Fuel is essential for the engine to produce energy. However, if there are any fuel-related issues, your engine will struggle to operate effectively. Here are some of the fuel problems your car can face:
- Clogged fuel filter: Over time, the fuel filter gets clogged with dirt and dust. This leads to less fuel movement to the engine, reducing the air-fuel ratio and fuel starvation. If proper fuel doesn’t reach the engine, it will consistently misfire.
- Low fuel pressure: In case the pressure of your car’s fuel drops, it doesn’t reach the combustion chambers of the engine. The air-fuel mixture becomes leaner, resulting in engine misfire.
- Defective fuel injector: The fuel injector passes the same amount of misted fuel to the combustion chamber at regular intervals. If this injector clogs or fails to pass fuel, the cylinder will not receive enough fuel to run the engine properly.
Air leaks
Air is as important for the engine to work smoothly as fuel. It mixes with the petrol/diesel and burns in the combustion chamber. This movement causes wasted gases to pass through the exhaust system. If there is a problem in the exhaust system, it can quickly lead to engine misfires. Here are some of the possible issues you may face:
- Vacuum leaks: A vacuum is produced during the combustion process to draw the required air into the fuel. More air may enter the combustion system due to a leak in the vacuum hose. Such problems quickly lead to engine misfires.
- Exhaust system issue: A backpressure forms when the exhaust pipe is clogged or the catalytic converter gets choked. It disrupts the overall engine performance.
Engine wear
An engine requires consistent maintenance similar to other car components. A neglected engine results in wear and tear, ultimately leading to misfires during a drive. Here is how the engine begins to malfunction:
- Faulty timing belt: A timing belt ensures that the engine valves open/close according to the piston movement. If the belt is slipping or the chain is stretched too far, combustion doesn't happen at the right time. This problem leads to severe engine damage and misfires.
- Worn-out piston rings: The piston rings seal the combustion chambers of the engine. These components prevent excess oil from entering the cylinders and maintain efficient combustion. However, once the piston rings begin to wear off or get damaged, the fuel economy drops. Such issues not only increase oil consumption but also cause misfiring.
Electrical faults
Apart from air, fuel, and spark plug issues, electrical hindrances can also lead to engine misfires. Here’s how:
- Bad oxygen sensor: The O2 sensor analyses the amount of oxygen remaining in the exhaust system. The information is then sent to the computer to ascertain the air-fuel mixture. If this sensor is not working properly, it can lead to a rich or poor air-fuel mixture and potential disrupted combustion.
- Poor MAF sensor: Cars rely on the Mass Airflow (MAF) sensor to measure how much air is entering the engine. If this sensor is defective, the engine’s program may not be able to ascertain how much air is mixing with the fuel. Under- and over-consumption can lead to engine misfires.
Key signs that indicate engine misfiring
Engine misfiring needs to be detected at early stages to avoid expensive repairs. So, look out for the following signs to detect if your car’s engine isn’t working as required:
Rough idling
Your car's acceleration power begins to reduce, and you also experience uneven idling. This means that your car slightly jumps up and down during a drive due to a disrupted air-fuel ratio. This rough performance is one of the first signs that your car’s engine is misfiring, and you need to go to a mechanic.
Poor pickup or power loss
Is your car not responding as swiftly as it usually does? Are you feeling that it is sluggish and not picking up power? Is there a shaking or jerking motion when you accelerate for speed? These are signs that the engine is taking on more load than usual, indicating a possible misfire.
More fuel use
When the engine misfires, your car's fuel economy drops. If you are watching the mileage consistently drop and need to visit the fuel station more than usual, it is time to get the engine checked.
Check the engine light on
You may notice that the engine light on your dashboard is on. This indicates that there is an issue with the engine that requires urgent mechanical attention. In this case, the car’s onboard system has detected a misfire that requires repair.
Black smoke
If a cylinder doesn’t detonate effectively, the air-fuel mixture may ignite within the exhaust system. In this situation, thick black smoke will come out of the pipe. This indicates that one of the cylinders is not functioning properly.
Strange engine sounds
The engine generally makes a rhythmic noise when working. However, in case of a misfire, you may experience odd banging, chuffing, or popping sounds. Such noises are mostly felt when the engine runs between 1,500 and 2,500 rpm. This means the engine is misfiring and requires urgent attention.
How to Fix a Car Engine Misfiring?
A mechanic visit is in order if you are dealing with any of the above problems. Here are some of the things that will happen when diagnosing and fixing the engine issues:
- OBD2 scan to identify which parts are not functioning properly.
- Spark plugs and ignition coils may need to be replaced.
- Fuel pressure check to detect if the engine is getting an accurate air-fuel mix.
- An Evaporative Emission Control (EVAP) smoke machine tests for the vacuum leaks.
Some of these diagnostic tests can be expensive, but they are mandatory for effective engine performance. However, you can save yourself from the hefty repair cost if you practice the following to prevent engine misfires:
Regular service and check-ups
Keeping your car in good condition means getting it serviced regularly. This helps catch small issues early, keeps your engine, brakes, fluids, battery, tyres, and filters in check, and improves performance and fuel efficiency. Skipping servicing can lead to bigger problems, lower mileage, and reduced resale value.
If you are looking for a convenient way to service your car, ACKO Drive service centres make the process simple. You can book easily through our app or website, and we take care of everything, from doorstep pickup to a careful 50+ point inspection with original parts.
Replace spark plugs and filters on time
If your car service is done on time, the mechanic will replace the old spark plugs, clean out the fuel filters, and monitor the air-fuel mixture. This will help ensure that the car runs smoothly for a long time without requiring expensive repairs.
Use good fuel
A high-quality fuel minimises carbon build-up in the combustion chamber and maintains a smooth engine performance. It helps reduce the chances of engine misfire and also increases the mileage in the long run.
Bottom Line
Taking care of your vehicle is key to keeping its value intact and your car’s engine running smoothly for the long haul. By sticking to regular check-ups, using quality fuel, and responding quickly to the check engine light, you can greatly reduce the chances of engine misfires.
If your car starts jerking, slowing down, or idling roughly, don’t ignore it—these are clear signs something needs your attention. Acting fast can save you from expensive repairs and keep your engine in top shape.
Your vehicle communicates with you through these warning signs, so listen closely. Scheduling regular maintenance not only protects your car but also saves you time and hassle down the road.
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