Checking the engine power system

The main indicator of the health of the engine power system is the fuel pressure in the fuel rail. But first, we recommend checking the condition of the air filter (see «Checking and replacing the air filter element»), because this procedure is simple and does not take much time. After you make sure that the air filter is clean, check the reliability of the electrical contacts in the wiring harness blocks of the injection system units responsible for supplying fuel (electric fuel pump, injectors).



Checking the fuel pressure in the fuel rail of the engine is only possible with a pressure gauge with a set of adapters for connecting to the fuel pipeline.

1. Turn on the ignition and listen: within a few seconds you should hear the sound of the electric fuel pump. If it is not audible, check the electrical supply circuit of the electric fuel pump.

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 serviceable electric fuel pump should have created pressure in the system, so not turning it on in this case is not a malfunction.

2. The procedure for checking fuel pressure is described in Sec. «Engine» (see «Checking fuel pressure in the power system»). With the engine idling, the pressure in the fuel line should be about 3 kgf/cm².

The following reasons for pressure drop are possible:

• faulty fuel pressure pulsation compensator;
• faulty fuel pressure regulator (built into the fuel pump module);
• clogged fuel filter (built into the fuel pump module);
• fuel pump faulty (installed in the fuel tank).

You can find ways to troubleshoot these problems in Sec. «Engine» (see «Supply system»).