The main criterion for the health of the engine power system is the fuel pressure in the fuel rail
If the fuel pressure is low, then the following are possible:
- - unstable engine operation;
- - stop the engine at idle;
- - increased or decreased idle speed of the crankshaft;
- - insufficient throttle response of the car;
- - jerks and dips in the engine when the car is moving
To check the fuel pressure, you will need a pressure gauge with a hose to connect to the fuel line
Turn on the ignition and listen, for a few seconds you should hear the sound of the electric fuel pump
If you can't hear it, you need to check the electrical circuit
It must be borne in mind that the electric fuel pump does not turn on if there is pressure in the fuel supply system.
Preparing the car for checking fuel pressure
We reduce or reset the fuel pressure in the power system, as will be described below
Remove the air filter
Remove the plastic safety cover of the fuel line coupling
Disconnect the fuel lines by squeezing the clamps of the coupling
Connect a pressure gauge between the fuel supply line and the fuel rail
Starting the engine.
With the engine running at idle, the fuel pressure must be at least 304 kPa (3.0 kgf/cm2)
The following reasons for pressure drop are possible:
- - faulty fuel pressure regulator (installed in the fuel pump module);
- - the fuel filter built into the fuel module housing is clogged, the mesh filter-fuel receiver of the electric fuel pump or the electric fuel pump is faulty;
- - the fuel pressure pulsation compensator installed on the fuel rail is faulty
Pressure reduction in the supply system
To carry out work on the repair of the power supply system on a just stopped engine, it is first necessary to reduce the pressure in the power supply system
We prepare the car and disconnect the negative battery terminal
Turn off the fuel pump by disconnecting the wiring block from it
We connect the negative terminal to the battery, start the engine and let it run until the fuel is completely depleted from the fuel rail. After that, the engine will stall
Turn off the ignition. Now you can disconnect the fuel lines.