If the fuel pressure is insufficient, the following may occur: – unstable engine operation; – engine stop at idle speed; - increased or decreased crankshaft speed at idle; - insufficient responsiveness of the car (the engine does not develop full power); – jerks and dips in engine operation when the vehicle is moving.
To begin with, we recommend checking the reliability of the electrical contacts in the wiring harness pads of the injection system units responsible for fuel supply (fuel pump, injectors).
Checking the fuel pressure in the fuel system is only possible if you have a pressure gauge with a hose for connection to the fuel line.
1. Turn on the ignition and listen: the sound of the electric fuel pump should be heard for a few seconds. If you cannot hear it, check the electric power supply circuit of the pump.
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 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 (see Reducing pressure in the engine fuel system).
3. Squeeze the fuel rail connector clamps…
4….and disconnect the fuel supply line from the fuel rail.
5. To check the fuel pressure, connect a pressure gauge (with a measurement limit of at least 5 kgf/cm²) between the fuel supply line and the fuel rail. With the engine idling, the pressure in the fuel line should be at least 365 kPa (3.65 kgf/cm²).
The following are possible reasons for the decrease in pressure:
– the fuel pressure regulator is faulty (depending on the engine type, it is installed in the electric fuel pump or on the fuel rail);
– fuel filters (installed in the electric fuel pump) are clogged or the electric fuel pump is faulty;
– the fuel pressure pulsation compensator is faulty (installed on the fuel rail of the 1.6 l Duratec Ti-VCT engine).
Methods for troubleshooting these faults are described in the subsection Removal, repair and installation of the fuel module.
(The original can be found on the specified resource FORDBOOK.ru)