• Author:
• Origin:
• Time of issue:2021-04-27 15:09
• Views:

(Summary description)
　　The electric fuel pump is affected by dry ① hot air resistance; ② the decrease of the pump oil volume caused by dirty blockage. If the gasoline tank is cleaned irregularly, the filter at the oil pump inlet is blocked. After the oil pump and the filter are cleaned, the pump oil cannot be pumped. Return to normal; ③The decline or failure of pumping oil is mostly caused by the oil filter being dirty or connected reversely. Sometimes the heat load is increased due to the delay in refueling; ④The carbon brushes, springs, commutator segments, and windings heat up and wear and tear. The resistance value becomes larger; ⑤ The speed of the oil pump decreases, and the oil pressure and oil volume decrease, causing the oil pump to fail.

　　 The car appears ① difficult to start; ② unstable idling; ③ poor acceleration, weak driving, stop-and-go, how to know that the electric fuel pump is malfunctioning, please see below

　　Inspection method of automobile electric fuel pump
　　①Check the working condition of the electric fuel pump
　　The inspection method is: first use a jumper to short-circuit the two detection jacks on the fault detection socket, and then turn on the ignition switch (don't start the engine). At this time, the running sound of the fuel pump should be heard from the fuel tank. If you can't hear the sound of running clearly, you can pinch the gasoline hose with your hands and you should feel the pressure of oil delivery. Otherwise, it indicates that the electric fuel pump is not working, and the power fuse, relay and control circuit of the electric fuel pump should be checked for faults. If everything is normal, the electric fuel pump should be disassembled and inspected.

(1) Connect the fuel pump test terminal on the diagnostic socket to the 12V power supply with a dedicated wire;

(2) Turn the ignition switch to the "ON" position, but do not start the engine;

(3) Unscrew the fuel tank cap to hear the sound of the fuel pump, or pinch the fuel hose with your hands to feel pressure;

(4) If you cannot hear the working sound of the fuel pump or there is no pressure in the fuel inlet pipe, the fuel pump should be overhauled or replaced;

(5) If the fuel pump does not work and the above inspection is normal, check whether the fuel pump circuit wires, relays, and fusible wires are open.

　　②Detect the resistance of the electric fuel pump
　　 Use a multimeter to measure the resistance (coil) of the two terminals on the electric fuel pump. The resistance should be 2～3Ω (20～40℃). Otherwise, the electric fuel pump should be replaced.


　　③Measurement of electric fuel pump pressure and holding pressure
　　 The measurement method is: the battery voltage should be above 12Y, remove the battery negative cable, release the oil pressure of the fuel system, and connect the oil pressure gauge. After reconnecting the battery negative cable, short-circuit the two detection holes of the electric fuel pump with a jumper, then turn on the ignition switch, let the fuel pump work, and read the oil pressure of the oil pressure gauge. The value should meet the requirements. If it is higher than the specified value, the pressure regulator should be replaced; if it is lower than the specified value, check whether there is oil leakage in the fuel delivery hose and connection, and check whether the fuel pump, gasoline filter and gasoline pressure regulator are normal Wait.

　　 Fuel pump disassembly and inspection
　　 Attention when disassembling the fuel pump: Release the fuel system pressure and turn off the electrical equipment. After removing the fuel pump, measure the resistance between the two terminals of the fuel pump, and it should be 2~3Q.
　　 Use the battery to directly energize the fuel pump, you should be able to hear the sound of the fuel pump motor rotating at a high speed. Note: The energization time should not be too long