Function of the car oil pump
The automotive fuel pump usually refers to the fuel pump, whose core function is to draw fuel from the fuel tank and pressurize it to deliver it to the engine. However, in professional contexts, "oil pump" can also refer to the oil pressure pump, and the two have different functions, so they need to be distinguished.
The core function of the fuel pump
The fuel pump is a key component of the fuel supply system, and it is mainly responsible for the following tasks:
- Transporting fuel: Overcoming the distance and height difference between the fuel tank and the engine, extracting fuel from the fuel tank and delivering it through the pipeline to the combustion chamber of the engine.
- Establishing pressure: Providing a stable working pressure (usually 3-5 bar) for the fuel injection system to ensure good fuel atomization and improve combustion efficiency.
- Maintaining system operation: Preventing air blockage in the fuel system and providing a certain cooling effect through fuel circulation.
The difference between the fuel pump and the oil pump
In some contexts, "oil pump" refers to the oil pressure pump, whose functions are completely different:
- Lubricating the engine: Drawing oil from the oil pan to the surfaces of all moving parts to reduce wear.
- Cyclic filtration: Making the oil continuously circulate in the lubrication path and passing through the filter to remove impurities.
A brief description of the working principle
- Electric fuel pump: Used in modern cars, it is located in the fuel tank and is driven by an electric motor to rotate the impeller to generate suction and pressure.
- Mechanical fuel pump: Used in older cars, it is driven by the camshaft of the engine to operate the diaphragm.
When the automotive fuel pump is damaged, the most typical symptoms are difficulty starting, weak acceleration, abnormal noises during driving, engine shaking, and the engine fault light coming on. These manifestations are usually caused by insufficient or interrupted fuel supply pressure and require a comprehensive judgment based on multiple details.
Starting and idle performance
- Difficulty starting: Cold start requires multiple attempts to ignite, or no response after the first start after parking, due to insufficient fuel pump pressure causing air to enter the fuel pipeline.
- Idle shaking: The engine speed fluctuates, the idle is unstable, and in severe cases, black smoke is emitted from the exhaust.
- Difficult starting in hot conditions: When the high-pressure fuel pump is damaged, it may be difficult to start the engine in hot conditions, and there is a smell of gasoline at the oil pan area.
Driving and power performance
- Weak acceleration: The engine does not respond quickly during sudden acceleration, with a jerking sensation, especially on uphill or when overtaking.
- Engine stall while driving: The engine suddenly stalls while the vehicle is running, especially at high speed or under heavy load, threatening driving safety.
- Unstable fuel supply: Inconsistent fuel supply may cause frequent engine restarts, thereby increasing fuel consumption.
Sound and warning signals
- Abnormal noise: A "buzzing" sound is heard from the rear seat area or the fuel tank location, varying with the throttle depth, which is a signal of motor or bearing wear.
- Fault light on the dashboard: The engine fault light on the dashboard comes on, and the ECU detects abnormal fuel pressure and issues an alarm.
The most common cause of the failure of the automotive fuel pump is circuit faults, damage to the fuel pump itself, or blockage of the fuel path. The common causes are concentrated in the power supply, mechanical, and fuel quality aspects.
Is there a problem with the circuit?
- Burned fuse or relay: The fuse in the fuel pump power supply line melts or the relay fails, causing the fuel pump to lose power.
- Poor contact of the lines: Loose, broken, or abnormal control signals from the ECU, preventing the fuel pump from receiving the working instructions.
Is the fuel pump itself damaged?
- Burned motor or wear and tear: After long-term operation, the plunger spring breaks, the pump body gets stuck, or the motor overheats and is damaged, directly cutting off the fuel supply.
- Damage to the driving gear: In some models, the fuel pump is driven by the engine, and loose or broken gears will affect the operation.
Is there an impact from the fuel path and fuel quality?
- Filter or filter blockage: Impurities in poor-quality fuel accumulate on the filter or gasoline filter, increasing the resistance to fuel intake.
- Low fuel level: When the fuel tank is low on fuel, the fuel pump motor lacks cooling and lubrication, and is prone to overheating and stopping.
In such cases, it is recommended to first check the fuses and relays, then measure the voltage of the oil pump. If necessary, seek professional maintenance personnel for inspection and replacement.
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