With insufficient fuel pressure, the following are possible:
- unstable engine operation;
- stop the engine at idle;
- reduced idle speed of the crankshaft;
- poor vehicle handling (engine does not develop full power);
- failures in the engine when the car is moving.
To begin with, we recommend checking the reliability of the electrical contacts in the blocks of the ECM wiring harnesses responsible for the fuel supply (fuel pump module, injectors, fuel relay and related fuses).
The fuel pressure in the power system is checked using a professional pressure gauge and a hose with an original fitting for connecting to a valve located on the fuel rail.
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.
Note. If you turned on the ignition three times without trying to start the engine, the electric fuel pump will not turn on again, which is not a sign of a malfunction. It will turn on simultaneously with the start of the engine start by the starter.
2. Reduce the pressure in the supply system (see «Reduced fuel pressure in the engine power system»).
3. Turn away a protective cap of the union for control of pressure of fuel on an end face of a fuel stage. Please note that the cap has an o-ring. If the ring is torn or has lost elasticity, replace it or the entire cap.
Note. For clarity, the work is shown with the decorative engine cover removed.
Note. If it is not possible to use a professional pressure gauge, use a conventional pressure gauge with hose and clamp. The pressure gauge must be with a measurement scale of not more than 1000 kPa (10 kgf/cm2) and division value not more than 20 kPa (0.2 kgf/cm2). Pay attention to a reliable connection (rolling) manometer and hose.
4. Using the metal protective cap of the tire valve, unscrew the spool (same as tire) …
Note. When turning out the spool, a small amount of fuel may leak out, so first place a rag under the fitting.
5.... and remove it from the fitting.
6. Connect a hose with a pressure gauge to the fitting. Fasten the hose to the fitting with a clamp and check the reliability of its fastening. Start the engine and check the pressure on the pressure gauge. It should be 380-400 kPa (3.8–4.0 kgf/cm2).
The following reasons for pressure drop are possible:
- faulty fuel pressure regulator;
- clogged fine fuel filter or fuel inlet filter;
- faulty electric fuel pump.
7. Stop the engine and reduce the pressure in the power system (see «Reduced fuel pressure in the engine power system»).
8. Disconnect the pressure gauge from the pressure control fitting, screw the spool into the fitting and install the protective cap on the fitting.