How to simply judge the quality of the fuel metering unit?

The role of the automobile metering unit is to control the oil intake and return flow of the high-pressure oil pump, thereby controlling the oil supply of the oil pump plunger to the rail, meeting the set pressure of the common rail system, and forming a closed loop control of the rail pressure with the rail pressure sensor. The internal structure of the fuel metering unit is not complicated. It consists of three parts: a housing with an electromagnetic coil, an upper cover with an oil hole, and a valve core that can move up and down. When it is damaged, just replace it with a new one.

A good metering unit can ensure the normal operation of the engine in the most fuel-efficient state.

The fuel metering unit is generally installed at the fuel inlet of the high-pressure fuel pump. It is a proportional solenoid valve, controlled by the electronic control unit (ECU), which can control the amount of fuel entering the high-pressure fuel pump, thereby controlling the oil pressure in the common rail pipe. The good work of this component can not only ensure that the vehicle can run normally, but also enable the engine to run in the most fuel-efficient state, achieving the effect of fuel saving.

How to simply judge the quality of the fuel metering unit? There are three commonly used methods to judge the quality of the metering unit.

Measure the resistance of the measuring unit, which is normally between 2.6-3.15 ohms

When the engine malfunctions as described at the beginning of the article, a simple method can be used to judge the quality of the metering unit. Generally speaking, at a room temperature of 20°C, the coil resistance of the measuring unit is between 2.6 and 3.15 ohms. If the resistance is not within this range, it can basically be judged as damaged.

Knock the metering unit lightly

Knock the metering unit lightly on your hand, and you should hear an obvious ‘popping’ sound from the valve core, otherwise the metering unit is stuck.

Use special tools to disassemble the metering unit to check the valve core wear

Note that the fuel metering unit cannot be disassembled at will, pay attention to the entry of dust, and be sure to keep it clean.

Detecting fuel metering units requires professional tools. For example, a fuel metering unit adjusting device can adjust the driving current of the driving metering unit, but some people can use simple methods to detect the quality of the fuel metering unit.

Use a fuel metering unit with a DC stabilized power supply with the same driving voltage to detect the quality of the fuel metering unit. Generally, the working current of the dosing unit is gradually adjusted in mA to increase the driving current while blowing the metering unit valve hole with the mouth to see whether the ventilation rate Increase with the increase of current. Of course, this can only roughly judge the working condition of the measuring unit.