What are the symptoms of a faulty fuel pressure sensor?
3 Answers
Fuel pressure sensor is used to detect the changes in fuel pressure in the fuel pipeline. If it is damaged, it cannot detect the fuel pressure, and the engine computer cannot adjust the fuel pressure according to the working conditions. Therefore, the car may experience symptoms such as weak acceleration or failure to start. More information about the fuel pressure sensor is as follows: 1. Function of low-pressure fuel pressure sensor: The engine control unit uses the sensor signal to control the low-pressure fuel system. The engine control unit sends a signal to the fuel pump control unit according to the sensor signal, allowing it to adjust the electronic fuel pump as needed based on the sensor signal. Impact of sensor signal failure: If the fuel pressure sensor fails, the fuel pressure pre-regulation replaces the fuel pressure regulation. The fuel pressure is about 6.5 bar. 2. Function of high-pressure fuel pressure sensor: The engine control unit analyzes the sensor signal and adjusts the pressure in the fuel distributor pipeline through two fuel metering valves. Impact of sensor signal failure: If the fuel pressure sensor fails, high fuel pressure cannot be established. The engine operates in low-pressure fuel emergency mode, resulting in loss of power and torque.
My car once had a fuel pressure sensor failure, and the symptoms were really annoying. When starting, the engine wouldn't fire up no matter what, and it took several attempts to get it going. While driving, the engine would shake badly at low speeds, and acceleration felt sluggish, as if being held back from behind. The dashboard warning light was constantly on, alerting me to the issue. Fuel consumption was also noticeably higher than usual, adding up to a significant increase in gas expenses over a month. When I took it to the repair shop, the mechanic said the faulty sensor caused the computer to misjudge the fuel pressure, leading to either too much or too little fuel being delivered. If left unfixed, this issue could potentially damage the fuel injectors or cylinders over time. After the repair, I developed a habit of regular check-ups to avoid major troubles in the future.
I've driven quite a few cars, and when the fuel pressure sensor fails, common symptoms include abnormal engine behavior. It can cause difficulty starting or stalling because the sensor sends incorrect readings to the ECU, affecting fuel regulation. While driving, you might notice unstable idling and increased vibrations, especially during cold starts. Acceleration response becomes sluggish, and fuel consumption may increase by more than 10%—quite a waste when you calculate the extra fuel costs. I recommend first checking the OBD fault codes to see if they indicate a sensor issue. Alternatively, observe the fuel pressure gauge; if the actual fuel pressure is normal but the ECU shows abnormalities, that's a clear sign. Ignoring it could turn a minor issue into major damage to the fuel injection system, so it's best to seek professional repair early on.
