How to repair and adjust the electronic fuel injection system of Truck

1.check the Engine Control Unit

The computer is the key to the electronic fuel injection system, and abnormal operation of the computer can cause various malfunctions and even malfunction of the electronic fuel injection system. However, the computer itself is the least likely component to malfunction, so it is generally not advisable to suspect the computer or touch it easily. Once the computer is damaged, it can only be replaced, and it is best to prepare a computer in advance for replacement inspection.

2.Check the fuel pressure regulator

When checking the fuel pressure regulator, the fuel pressure should be released first. The method is to remove the protective cap from the pressure pipe joint, install a pressure reducing valve on the pipe joint and slowly tighten it to release the pressure, then remove the pressure valve and install the protective cap. When reducing pressure, be careful to collect the emerging fuel with a container or cover it with a towel. If the pipe joint is loosened without reducing pressure, high-pressure oil will spray out.
The disassembled fuel pressure regulator can be put into gasoline and cleaned of dirt near the ball valve by inflating it with a pump; If the spring of the pressure regulator fails, it should be replaced.
The fuel pressure should be checked when the engine is cold. The fuel pressure gauge can be installed next to the electromagnetic fuel injection valve supply manifold, and the pressure regulator return pipe can be clamped before driving the electric fuel pump. If the oil pressure is higher than 317kPa, the pressure regulator should be checked.

3.Check the electric fuel pump

There are three prerequisites for the good operation of an electric fuel pump, namely that the components are not worn (the rollers are tightly attached to the pump wall without oil leakage), the electric motor is intact, and the inside of the pump is clean.
When checking the electric fuel pump, three aspects should be taken into consideration. Firstly, check whether the fuel filter is in good condition, whether the fuel tank has fuel and is clean, and disassemble the fuel pump for cleaning; At the same time, check for wear on the rollers and pump walls. If there is slight wear, replace the rollers. If there is severe wear, replace the pump body with a new one; Whether the motor is intact can be determined by measuring the armature coil with a multimeter.

4.Check the electromagnetic fuel injection valve

Check the electromagnetic fuel injection valve, mainly to check whether the internal oil circuit is blocked, whether the needle valve is not tightly closed, and whether the electromagnetic coil is working properly. When checking, you can first use the cylinder by cylinder fuel cut-off method to find out which cylinder’s electromagnetic fuel injection valve is faulty, and then follow the following steps to check: first connect the 12V power supply voltage to one end of the fuel injection valve wiring socket, repeatedly disconnect the other end of the body and intermittently contact it, observe whether there is a slight vibration sensation, and listen for a “click, click” micro spray sound. If not, check if there is a fault in the circuit connected to the fuel injection valve; Next, check if the fuel supply pipeline is blocked; Then check if the inlet of the fuel injection valve is blocked, and then check if the electromagnetic coil is open and if the fuel injection hole is blocked.