Checking the pressure sensor

Disconnect the hose at the pressure sensor and close with your finger

Have your assistant start the engine with the starter and bring it up to medium speed (about 2000 rpm).

With an even speed, reconnect the hose to the sensor.

Since there is again a reduced pressure on the sensor, the ignition timing adjustment on the control unit side should work. With the same position of the gas pedal, the engine noticeably increases speed.

If the RPM remains constant, this indicates a leaky vacuum hose or a defective pressure sensor. The engine confirms this with reduced power and degraded exhaust gas values.