Fuel Pressure Regulator

HOW TO DETECT THE FUEL PRESSURE CONTROL VALVE FAILURE

The component inspection is quite laborious and is usually performed as part of the vehicle fuel system comprehensive diagnosis.

As a start. check that there is enough fuel in the tank. Then you have to check the battery voltage. since the pressure of the fuel supply is directly dependent on it. It should be 12V. After that. you need to disconnect the negative terminal from the battery. connect a pressure gauge to the fuel system. wipe off spilt gasoline. reconnect the negative terminal to the battery. and start the engine in idle mode. Then disconnect the vacuum hose from the valve. plug its end with your finger. and measure the pressure. It should be 0.25-0.35 MPa in engines with multi-point injection. and 0.07-0.10 MPa in engines with throttle body injection.

If the pressure is excessively low. squeeze the return hose. and then check the gauge readings. Increase of the pressure to normal indicates the valve malfunction. Too high measurement results also indicate its failure in the case if the throughput capacity of the return pipeline is not impaired.

When the engine has warmed up. connect a vacuum hose to the valve. The pressure should drop by an average of 0.05 MPa. If it stays at the same level. the vacuum pipeline may be clogged up. or the valve has failed.

To measure the system’s residual pressure. shut down the engine. block the fuel tank and repeat the measurements in 10 minutes. Compare the obtained values with the values specified in the vehicle technical documents. If the system pressure is below normal. you probably have to replace the fuel pressure control valve.