The difference of Fuel pump metering valve

The Fuel metering valve is a spare part on the fuel pump to control the feeding of the oil into the pump. The fuel metering valve solenoid is powered from a system relay on the positive side and the ECU switches the negative side to the ground. The duty cycle of the signal determines the position of the plunger, increasing the duty cycle will increase the fuel pressure, decreasing the the duty cycle decreases the fuel pressure.
Normally, There are two types fuel metering valve, please check the picture below. The most obvious difference is the plug of the valve which connecting the wires, “Bent head” and “Straight head”. If the plug is “Straight head”, it is always OPEN, and used for Engineering machinery vehicles, like trucks etc, with 6 cylinders. If the plug is “Bent head”, it is always CLOSED, and used for small car with 4 cylinders.

Noted: OPEN and CLOSED means when the power is off, the State of the fuel metering valve.