SEQUENCE OF WORKS
1. Disconnect the hose from the pressure sensor and close its free end with your finger.
2. The assistant should start the engine and maintain the crankshaft speed at 2000 min⁻¹.
3. With the engine crankshaft speed the same, reconnect the hose to the sensor.
4. Since a vacuum appears in the sensor, the control unit should begin to regulate the ignition timing advance. With the same accelerator pedal position, the engine crankshaft speed should increase significantly.
5. If the crankshaft speed remains unchanged, this indicates a leak in the vacuum hose or a faulty pressure sensor. This reduces engine power and increases the content of harmful substances in the exhaust gases.