What is the normal pressure for the Envision's high-pressure fuel pump?
2 Answers
The normal fuel pressure for most gasoline vehicles is between 300-350 kPa. If the fuel pressure is too low, the fuel injector may spray weakly or not at all. If the pressure is too high, it may damage the fuel lines or the fuel injector. Working principle of the fuel pressure pump: The fuel pressure is regulated by the coordination of the spring and the vacuum in the chamber. When the fuel pressure exceeds the standard value, the high-pressure fuel moves the diaphragm upward, opening the ball valve and allowing excess fuel to return through the return line. When the pressure is below the standard value, the spring presses the diaphragm to close the ball valve, stopping the return flow. The pressure regulator's role is to maintain a constant pressure in the fuel line. Method for testing automotive fuel pressure: Turn the ignition switch on (without starting the engine) to activate the electric fuel pump. The fuel pressure at this time should meet technical specifications, generally fluctuating around 0.3 MPa.
I've been repairing the Envision for many years, and the normal values for the 2.0T engine's high-pressure fuel pump vary by model. For the older LTG engine, the rail pressure typically fluctuates between 150 and 200 bar during operation, and dropping to around 140 bar at idle is also normal. The newer LSY engine's high-pressure direct injection system operates at much higher pressures, with the high-pressure fuel rail reaching 2500-3500 psi (equivalent to 170-240 bar) during normal driving, sometimes even exceeding 4000 psi during hard acceleration. Actual values will be displayed on the diagnostic tool. If a fuel pressure fault code appears, a deviation of over 50 bar usually warrants a closer inspection of the fuel pump and pressure sensor. In hybrid mode, the pressure may differ, so connecting to a computer to view real-time data streams is the most accurate method.
