Engine Misfire? Check These Three Parts

Engine misfire is a common fault that not only causes a decrease in power and a surge in fuel consumption, but may also damage key components such as the three-way catalyst. Many car owners are at a loss when encountering such problems. In fact, by prioritizing the inspection of the ignition system, fuel system, and intake system, most of the causes of the faults can be identified.

1、 Ignition system: whether the spark is "awesome"

The ignition system is responsible for igniting the mixture of oil and gas, and is the "fuse" for the engine to do work, with the highest probability of failure. Focus on checking the spark plug to see if the electrode is worn, has severe carbon buildup, or has a large gap. The normal gap is usually 0.8-1.1mm, and excessive wear can lead to insufficient ignition energy. At the same time, check the ignition coil. If the coil is aging or has poor insulation, weak or no ignition may occur. The coil resistance can be detected by a multimeter or replaced to determine if it is faulty.

2、 Fuel system: whether the fuel supply is "smooth"

The fuel system needs to accurately provide atomized fuel, and abnormal fuel supply can directly lead to misfire. First, check the fuel injector. Carbon buildup, blockage, or insufficient injection pressure can cause poor fuel atomization. You can investigate by cleaning the fuel injector or testing the injection pressure. Recheck the fuel pressure sensor and fuel pump. Fuel pump failure can lead to low fuel supply pressure, while sensor abnormalities can transmit incorrect fuel supply signals. Both can be detected by professional equipment to see if the values are normal.

3、 Air intake system: whether the air intake is "sufficient"

An appropriate air-fuel ratio is required for the engine to perform power, as insufficient intake can disrupt the ratio and cause misfire. Priority should be given to checking the air filter, as blockage can cause a sharp decrease in air intake and requires timely replacement. Recheck the throttle valve and intake manifold. Carbon buildup can affect the intake flow rate and can be disassembled and cleaned. In addition, a malfunction of the intake pressure sensor can cause the ECU to misjudge the intake volume, and it is necessary to check whether the sensor value is within the normal range.

The above three parts cover the main causes of engine misfire. When troubleshooting, priority can be given to dealing with easily consumable and washable components in the order of "ignition fuel intake". Most simple faults can be solved through basic inspections. If the fire persists after investigation, it is recommended to promptly go to a professional repair shop to inspect the mechanical components of the engine.