Recirculation System

GENERAL INFORMATION

The system consists of the recirculation valve, check valve and thermal vacuum valve (TVV).

Inspection on Carburetor Engines

PROCEDURE

1. For inspection, disconnect the hoses from these valves and blow through them. Air should pass freely through the hoses.

2. For the check of the TVV, refer to subsection 6.4.1.1.2.

3. To check the EGR valve, disconnect the vacuum hose at the upper part. Connect an auxiliary hose and create vacuum in it. Check the diaphragm travel by placing a finger on the lower part of the valve. If the diaphragm does not move, replace the valve.

4. If the TVV is serviceable, check the check valve. To do this, warm up the engine and disconnect the vacuum hose from the EGR valve. Place a finger on the hose, quickly raise and release the engine speed. Vacuum should be felt in the hose as the speed increases, and it should decrease slightly when the speed is released. Otherwise, replace the check valve.

Check on fuel-injected engine The check procedure is the same as on carbureted engine, except that the solenoid valve is checked instead of the TVV.

The solenoid valve does not differ from the fuel vapor recovery system valve and is checked in the same way (refer to subsection 6.4.1.1.2).

EGR VALVE Replacement

PROCEDURE

1. The EGR valve on the fuel-injected engine (indicated by arrow) is mounted on the left side of the intake manifold. To access the valve, it is recommended to remove the air cleaner and the check valve. Disconnect the vacuum hose from the valve.

2. Loosen the union nuts and disconnect the EGR and check valve pipes.

3. Remove the 2 nuts, then remove the valve and gasket.

CHECK VALVE Replacement

PROCEDURE

1. The valve is mounted on the left side of the intake manifold (1 – screws, 2 – vacuum hoses). To access the valve, it is recommended to remove the air cleaner.

2. Disconnect the vacuum hoses from the valve.

3. Remove the 2 screws and remove the valve.

4. Install the valve in the reverse order.

TVV ON CARBURETED ENGINE Replacement Refer to subsection 6.4.1.1.2.

SOLENOID VALVE ON FUEL-INJECTED ENGINE Replacement Refer to subsection 6.4.1.1.2.

EXHAUST GAS SENSOR Check on carbureted engines

PROCEDURE

1. Adjust the idle mixture quality.

2. Open the diagnostic connector located under the fuse block.

3. Connect a voltmeter to the connector terminals.

4. Start the engine, raise the speed to 2000 rpm and observe the voltmeter for 2 min. If the sensor is serviceable, the voltmeter reading should change five times from 0 to 12 V every 10 sec. Otherwise, the sensor is faulty and a more precise check is required at a service station.

Check on fuel-injected engine If the CO content in the exhaust gases exceeds the norm, check the exhaust gas sensor for serviceability using the self-diagnosis function of the control unit.

CATALYTIC CONVERTER Replacement Refer to subsection 6.1.14 and subsection 6.2.16.

EXHAUST GAS SENSOR Replacement

PROCEDURE

Warning: After a drop or strong impact, the sensor may fail.

1. Disconnect the connector from the exhaust gas sensor.

2. Remove the wires from the clips.

2. Unscrew the sensor and remove it together with the gasket.

3. Install the sensor in the reverse order. Apply high-temperature grease to the sensor threads.