Carburetor engines (1.6 l) without catalytic converter
1. Check ignition timing (see subsection 7.7.7).
2. Make sure the spark plugs are in good condition and the spark plug gaps are correct (see subsection 2.2.3 and subsection 7.7.2).
3. Check throttle cable adjustment (see subsection 6.1.7).
4. Check the tightness of the crankcase ventilation hoses, the absence of kinks and leaks.
5. Check the cleanliness of the air filter and air ducts.
6. Check the condition of the exhaust system (see subsection 2.3.10).
7. If there are signs of abnormal engine operation, check the compression in the engine cylinders (see subsection 3.1.1.2).
8. Blend quality (CO content in exhaust gases) is set at the factory and is not adjustable during operation. However, if the composition of the mixture is disturbed (as a result of general engine wear, or after a carburetor repair), then the CO content can be restored, for which a gas analyzer is needed. If the device is not available, the adjustment is carried out at a workshop.
9. Warm up the engine after driving.
Attention! The mixture should be adjusted within no more than two minutes after the trip, without stopping the engine. If this is not possible, or if the cooling fan does not turn off, wait for the fan to stop. Deplete the excess fuel in the intake manifold by revving the engine to 2000-3000 rpm 2-3 times and idling the engine again.
10. Make sure all consumers are disabled. If the car is not equipped with a tachometer, then connect the tachometer in accordance with the instructions for this device. Determine and remember the idle speed, compare them with the normative ones.
11. The idle speed screw is located at the rear of the carburetor and is accessible behind the air filter. Turning or unscrewing the screw, set the required idle speed.
12. If there is a gas analyzer, then, in accordance with the instructions for the device, measure the CO content in the exhaust gases. If necessary, adjust the mixture with the quality screw, which is located directly below the idle speed screw.
13. By turning the quality screw at small angles, achieve the desired CO content in the exhaust gases. When turning the screw (clockwise rotation) the mixture becomes leaner and the CO level decreases, when the screw is loosened, the mixture is enriched and the CO level rises.
14. At the end, disconnect the instruments and check the idle speed again, adjust if necessary.
Carburetor engines equipped with a catalytic converter
1. Adjust idle speed.
2. Guided by paragraph 8, check and adjust the composition of the mixture at idle, for which proceed as follows.
3. Stop the engine and turn the ignition key to position "off". Disconnect the connector from the exhaust gas sensor (the sensor is screwed into the exhaust manifold) and from the solenoid air valve (mounted on the suction manifold on the left side.
4. Remove the cap from the exhaust gas sampling tube, which is located on the left side of the exhaust manifold, and attach a gas analyzer to this tube.
5. Start the engine. Deplete the excess fuel in the intake manifold by revving the engine to 2000-3000 rpm 2-3 times and idling the engine again. Make sure that the CO content corresponds to that specified in subsection 2.1.
6. If necessary, adjust the CO content by removing the restrictor sleeve from the carburetor with a thin tool to provide access to the mixture quality screw, which is located directly under the idle speed screw.
7. By turning the quality screw at small angles, achieve the desired CO content in the exhaust gases. It is measured in the exhaust pipe (arrow). When loosening the screw (clockwise rotation) the mixture becomes leaner and the CO level decreases, when the screw is turned in, the mixture is enriched and the CO level rises.
8. At the end, disconnect the device, install a new restrictive sleeve on the quality screw. Install the cap on the gas sampling tube, connect the connectors to the exhaust gas sensor and to the solenoid valve.
9. At the end, disconnect the device and check the idle speed again, adjust if necessary.
Fuel injected engines
1. Stop the engine and turn the ignition key to position "off". Disconnect the connector from the throttle angle sensor, which is mounted on the side of the throttle body.
2. Start the engine. Deplete the excess fuel in the intake manifold by revving the engine to 2000-3000 rpm 2-3 times and idling the engine again. Make sure the idle speed is as specified in subsection 2.1.
3. If necessary, adjust the idle speed by turning the adjusting screw, which is located on the right side of the throttle chamber (indicated by an arrow). Turning or unscrewing the screw, achieve the desired idle speed.
4. After adjustment, stop the engine and connect the connector to the throttle angle sensor.
5. The content of CO in the exhaust gases can be determined independently, with sufficient experience and qualifications, as well as the necessary equipment (including accurate tachometer and calibrated gas analyzer). However, if the need for CO adjustment is detected, then the probable cause may be a failure of the engine control system (ECCS systems). The content of CO is not subject to self-adjustment.
6. If a discrepancy between the CO content and the standard is detected, then check the serviceability of the exhaust gas sensor and parts of the fuel injection system using the ECCS self-diagnosis function for this (see subsection 6.2.11). If a malfunction is detected during the self-test, the car should be handed over to a car service for testing.