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Control system temperature of the intake air
 | To perform the diagnostic procedures described below require manual vacuum pump with a vacuum gauge. |
Hot air supply system Operating principle The efficiency of the combustion air-fuel ratio determined constant temperature of the carburetor intake air through the air cleaner, regardless of the temperature within the engine compartment. To fulfill this condition the air path between the dust separator and air cleaner assemblies enabled device controlling the temperature of the intake air.  | When the engine is cold and when the intake air temperature is below a predetermined bimetallic spring closes the thermostatic valve in the air cleaner (see. Illustration below - 4.2 l model). When this intake manifold vacuum applied to the vacuum motor, which closes the air inlet valve. When the valve is closed in an air cleaner through a separate entrance, which now opens on a flexible metal tube enters the hot air. Air heating is performed in a heater located on the exhaust manifold (on an accompanying illustration shows the components of the temperature control system of the intake air model 4.2 L). |
As the temperature rises in the air cleaner of the bimetallic spring thermostatic valve gradually allows access of air by reducing the depth of the vacuum applied to the vacuum motor. Simultaneously, a spring-loaded flap closes the hot air. Checking operation | - Remove the air cleaner assembly with the air intake hose.
- Make sure that when the engine intake valve is in the position of the access of cold air. Manually move the valve, checking the freedom of its movement.
- When a cold engine idle valve must be closed, allowing access of hot air. Disconnect the vacuum hose of the vacuum motor - should quickly open the damper, providing access of cold air. Plug the vacuum hose with your finger and make sure it reaches the vacuum of the vacuum motor.
- The correct functioning of the thermostatic valve can be checked by artificially cooling the compressed air and artificial heating of the hair dryer.
- The efficiency of the vacuum motor is tested by connecting it to a hand vacuum pump with a vacuum gauge. The inlet valve should begin to open at a depth of 72 mm Hg vacuum. Art. on l models 4.2 and 50 ?� 15 mm Hg. Art. 3.0 liter models. Full opening of the valve should occur at 146 mm Hg vacuum. Art. on l models 4.2 and 100 ?� 25 mm Hg. Art. 3.0 liter models. If necessary, replace the motor.
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The stabilizer (valve-compensator) rev the engine is warm The valve is a temperature-sensitive valve supplies additional air into the intake pipe of the hot engine (see. Accompanying illustrations - 4.2 l and 3.0 l engines). Thus there is a lean condition, which increases the stability of the idle speed and reduces emissions to the atmosphere of hydrocarbon compounds. Checking operation - model 4.2 l | - Remove the air cleaner assembly.
- At ambient temperature its vicinity below 60 ?� C canceller should be closed.
- Using a hair dryer, heat the compensator unit to a temperature of 74 ?� C and Blow in the union. The air must pass freely through the valve, otherwise replace the compensator.
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Checking operation - model 3.0 l | - Remove the air cleaner assembly.
- At ambient temperature its vicinity below 60 ?� C canceller should be fully closed.
 | - Using a hair dryer, heat the compensator unit to a temperature of 75 ?� C - compensator valve should be fully open, otherwise replace the unit.
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Preheating the air-fuel mixture - model 3.0 l Operating principle The system consists of a relay and a heating element assembly disposed between the base of the carburettor and intake manifold. When starting the engine the heater is energized to provide heating passing therethrough an air-fuel mixture. This increases the intensity of the fuel spray and decreasing emissions of carbon monoxide (CO). Checking operation | - When the engine is cold switch on the ignition (key in position ON).
- Put your hand on the throttle of the carburettor and make sure the temperature rises.
- If within a few minutes of heating does not occur, check the battery voltage in the electric connector of the heater.
- If voltage is present, and there is no heating, replace the heating element.
 | - If no voltage, check the relay (see. Accompanying illustration) and the state of electrical heater.
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- When completed, turn off the ignition.
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