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.
Warning: Keep in mind that the electric fuel pump will not turn on if there is pressure in the fuel supply system. In other words, if you have 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. Reduce the pressure in the fuel system and 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. With the engine idling, the pressure in the fuel line should be about 3 kgf/cm².
The following are possible reasons for the decrease in pressure:
- fuel pressure regulator malfunction;
- malfunction of the fuel pump or contamination of the fine fuel filter built into the fuel module;
- clogged mesh filter in the fuel pump module.
(Material is located on the source website: «www.RenaultBook.ru»)