Start the engine and warm it up to normal operating temperature. Stop the engine and remove the air filter.
Figure 2.25. Connecting a voltmeter to check the lean air-fuel mixture valve while coasting: B – connector contact
Disconnect the lean air/fuel mixture control system connector while coasting. Connect the voltmeter to the "B" pin of the connector and the "ground" pin (figure 2.25).
Start the engine. Increase the engine speed to 3000 min⁻¹, then sharply release the accelerator pedal and observe the voltmeter readings. At a speed of more than 2100+100 min⁻¹, voltage should not be registered; below this speed, the voltmeter should show a voltage of 12 V. Stop the engine and disconnect the voltmeter.
Figure 2.26. Applying voltage from the battery to check the lean air-fuel mixture valve while coasting
Check the operation of the lean air/fuel mixture valve while coasting by applying battery voltage as shown in the figure 2.26. When voltage is applied, a click should be heard.
Figure 2.27. Polarity of the voltmeter connection to the connector when checking the idle switch of the engine of the lean fuel-air mixture system when coasting and the location of the adjusting screw (1)
Check the idle switch as follows. Start the engine and connect the voltmeter to the connector as shown in the figure 2.27. When the engine is idling, no voltage should be registered. Increase the engine speed and check that at speeds above 1200–1300 min⁻¹ the voltmeter reading is 12 V. If necessary, turn the switch adjusting screw until the correct reading is obtained.
Stop the engine, disconnect the voltmeter and install the air filter.