As the core component of a car, the health of the engine directly affects the performance and safety of the vehicle. However, the engine will inevitably have various faults during long-term use. This article will introduce some common engine faults and their diagnostic methods.
1. Difficulty in starting the engine
Fault phenomenon: Turn on the ignition switch, turn the ignition switch to the start position, and the engine cannot start.
Possible causes of failure:
- Starting system failure: insufficient battery power, the electrode pile clamp is lifted or the electrode pile is severely oxidized; the main fuse of the circuit is blown; the ignition switch is faulty; the starter is faulty; the starting circuit is broken or the circuit connector is in poor contact.
- Fuel injection system failure: There is no fuel in the car tank; the fuel pump does not work or the pump oil pressure is too low; the fuel pipe leaks and deforms; the circuit breaker is disconnected; the fuel pressure regulator does not work properly; the fuel filter is too dirty.
- Electronic control unit failure.
Diagnostic method:
1. Check the storage condition of the battery and the connection and contact of the electrodes.
2. Check the starting circuit, fuse and ignition switch.
3. Press the accelerator to the middle open position, and then start the starter. If the engine can start, it means that the fault is the idle speed regulating valve and its circuit fault or the intake pipe leaks.
4. Perform a good appearance inspection to check whether the intake pipe is leaking; check whether all hoses and their joints are intact; check whether the hose of the crankcase ventilation device is leaking or broken.
5. Detect high-voltage sparks.
2. Engine overheating
Fault phenomenon: The cooling temperature exceeds the normal value, and the engine cannot dissipate heat normally, causing the engine to overheat.
Possible causes of failure:
- Antifreeze leakage.
- Engine thermostat and fan cooling failure.
- Radiator failure, fan failure, water tank blockage and other cooling system abnormalities.
Diagnostic method:
1. Check whether the antifreeze is leaking.
2. Check the working status of the engine thermostat and fan.
3. Check whether the radiator, fan and water tank are working properly.
3. Engine compartment odor
Fault phenomenon: The car has a pungent or burning smell while driving.
Possible causes of failure:
- Burning or coking of wires around the engine.
- Engine oil adheres to the engine surface, foreign matter evaporates or burns due to heat.
Diagnostic method:
1. Stop the car immediately and check whether there are softened or burned wires around the engine.
2. After eliminating the circuit fault, check whether the engine oil adheres to the engine surface, foreign matter evaporates or burns due to heat.
4. Acceleration powerlessness
Failure phenomenon: The engine is powerless when accelerating.
Possible causes of failure:
- Failure of ignition coil and spark plug leads to cylinder failure.
- Failure of air filter and gasoline filter.
Diagnostic method:
1. Check the working status of ignition coil and spark plug.
2. Check whether the air filter and gasoline filter need to be replaced.
5. Unstable idle speed
Failure phenomenon: The engine runs unstably at idle speed.
Possible causes of failure:
- Leakage in the intake pipe.
- Failure of the idle speed regulating valve and its circuit.
Diagnostic methods:
1. Check whether the intake pipe is leaking.
2. Check whether the idle speed regulating valve and its circuit are normal.
Conclusion
The diagnosis of engine failure requires comprehensive consideration of multiple factors, including the fault phenomenon, possible causes of the fault and diagnostic methods. Through systematic inspection and analysis, the specific location and cause of the fault can be effectively found, so that corresponding measures can be taken for repair and maintenance. Mastering these basic fault diagnosis methods will help us better maintain and care for our vehicles and ensure that they are always in the best working condition.
