Sometimes the engine even stalls. A jerk occurs at the moment the throttle valve opens, when, according to the signal from the throttle position sensor, the ECU determines the moment of transition from idle to load mode and must increase the amount of fuel supplied through the nozzles. With insufficient pressure in the fuel line, even with an increase in the injection duration, there is not enough fuel for a smooth start.
To check the fuel pressure, connect a pressure gauge with a measurement limit of 10 kgf / cm2 to a special fitting on the fuel line using a piece of a suitable hose2. With the engine running, the pressure in the fuel line must be at least 3 kgf/cm2.
Note. The design of the pressure test fitting is similar to the design of the wheel tire valve with a spool. Therefore, you can use the hose end of a foot tire pump to connect the pressure gauge hose.
The reasons for the decrease in pressure can be:
Faulty fuel pressure regulator
- faulty fuel pressure regulator. In addition, failure of the regulator may be caused by a loose hose fit on the regulator vacuum chamber fitting;
Clogged fuel filter
- clogged fuel filter;
Faulty fuel pump
- faulty fuel pump.
Note. Checking methods and pressure regulator replacement, fuel filter and fuel pump, see section «Engine» in subsection «Supply system».