Checking the fuel pressure in the engine fuel rail is only possible if you have a pressure gauge with a set of adapters for connection to the fuel line.
1. Turn on the ignition and listen: within a few seconds you should hear the sound of the electric fuel pump. If you do not hear it, check the electric fuel pump power circuit.
Attention! Keep in mind that the electric fuel pump does not turn on if there is pressure in the fuel supply system. In other words, if you previously turned on the ignition and tried to start the engine, then a working electric fuel pump should have already created pressure in the system and its failure to turn on in this case is not a malfunction.
2. Disconnect the pressure line from the fuel pump (see "Replacing the fuel pump").
3. To check the fuel pressure, connect a pressure gauge (with a measurement limit of at least 5 kgf/cm²) between the fuel pump and the pressure line. When the engine is idling, the pressure in the fuel line should be about 3 kgf/cm².
The following are possible reasons for the decrease in pressure:
- faulty fuel pressure regulator;
- clogged fuel filter;
- faulty fuel pump.
For troubleshooting methods for these problems, see the subsection "Power supply system".