printable version

The quality management system mixture during deseleratsii

To perform the diagnostic procedures described below need a hand vacuum pump with a vacuum gauge.

Operating principle

A deep depression in the intake manifold when the engine speed is dropped (deseleratsii) leads to the release into the atmosphere in the unburned combustible gases and oil, increase emissions of hydrocarbon compounds. In order to reduce the emission of hydrocarbon compounds carburetor equipped with a depletion of the mixture at deseleratsii (BCDD) (see. Accompanying illustration).

Upon reaching the depth of vacuum in the intake manifold certain value BCDD control valve opens the bypass air passage, resulting in a reduced amount of fuel injected into the carburetor through the cast nozzle. This increases the completeness of combustion of the mixture, which leads to a reduction in the emission of hydrocarbon compounds.

To avoid engine knock after the final stop, Manual transmission models are equipped with a solenoid valve BCDD, which blocks the action of the control valve BCDD.

Check control valve BCDD

Under normal conditions, the valve control BCDD does not need checking and adjusting, but if you need to adjust does occur, proceed as described below.

PERFORMANCE ORDER

On models with Manual transmission disunite an electric socket of the carburetor. Disconnection connector carburetor de-energizes the solenoid valves BCDD and fuel cut (shut-off), preventing their operation, which is why in the course of this test can not keep the engine idling. Fully loosen the damper fast idling (if applicable). Remove the air cleaner cover and connect a vacuum gauge to the intake manifold. Raise the engine speed to the value of 3000 ÷ 4000 per minute, then release the gas pedal. When you release the gas must change the frequency of the sound emitted by the carburetor throat. This change in frequency indicates the operation of the control valve BCDD. Recheck the last section, observing the vacuum gauge while changing the frequency of the sound. On models 4.2 liter unit should register the depth of negative pressure 570 ?� 50 mm Hg. v. on l models 3.0 - 580 ?� 50 mm Hg. Art. If you change the frequency of the sound does not occur, or the depth of the vacuum exceeds the standard value, remove the control valve BCDD rubber stopper and turn the adjusting screw clockwise. If the frequency still does not change, remove the valve from the carburettor BCDD and make sure it is activated plunger when applying vacuum. If necessary, replace the valve BCDD. Do not press the adjusting screw! If the change occurs at frequencies below the nominal depth of the vacuum, remove the plug and turn the adjusting screw counterclockwise, achieving the desired result. Adjust the damper fast idling.

Check solenoid valve BCDD

PERFORMANCE ORDER

Disconnect the electrical connector of the carburetor. Apply battery voltage to the terminals of the electromagnet in the carburetor connector (see. Accompanying illustration). 1 - 4.2 liters 2 - 3,0 l Should a click operation of the solenoid valve in the carburetor. Otherwise, replace the valve.