AutoZone 1987 Ford Country Squire 5.0L FI 8cyl | Repair Guides | Driveability & Emission Controls | Emission Controls | Crankcase Ventilation System | AutoZone.com

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    Suzuki Samurai/Sidekick/Tracker 1986-1998 Repair Guide

    Crankcase Ventilation System

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    OPERATION



    See Figure 1

    The Positive Crankcase Ventilation (PCV) system is designed to prevent engine blow-by gases, containing unburned hydrocarbons (HC) and carbon monoxide (CO), from being released into the atmosphere, and also helps to keep the engine oil clean, by ridding the crankcase of moisture and corrosive fumes. The PCV valve system vents crankcase gases into the incoming air charge entering the engine, where they are burned with the fuel and air mixture.

    1986-90 Models

    Crankcase blow-by gases flow through a passage in the engine block into the cylinder head. The gases exit the cylinder head through an opening in the rocker arm cover, and through a hose to a 3-way connector. At the 3-way connector, fresh incoming air from the air cleaner assembly is mixed with the blow-by gases. The fresh air/blow-by gas mixture is routed through a hose to the intake manifold. The mixture is introduced to the incoming air charge in the intake manifold, and is burned along with the air charge.



    Click image to see an enlarged view

    Fig. Fig. 1: Positive Crankcase Ventilation (PCV) system schematic

    1991-98 Models
    TFI ENGINES

    Crankcase blow-by gases flow through a passage in the engine block into the cylinder head. Under the rocker arm cover, fresh incoming air from the air cleaner assembly is mixed with the blow-by gases. The fresh air/blow-by gas mixture exits the cylinder head through an opening in the rocker arm cover, and through a hose to the intake manifold. The mixture is introduced to the incoming air charge in the intake manifold, and is burned along with the air charge.

    MFI ENGINES

    Crankcase blow-by gases flow through a passage in the engine block into the cylinder head. The blow-by gases exit the cylinder head through the PCV valve and into a hose leading to the intake manifold. The gases are introduced to the incoming air charge in the intake manifold, and is burned along with the air charge.

    COMPONENT TESTING



    Never adjust the idle speed without checking the PCV valve and hoses first, because a stuck PCV valve, plugged hose, or vacuum leakage from a PCV line can cause a rough idle.

    PCV Hoses

    Inspect all PCV system hoses for loose connections, leaks, clogs, and deterioration. Replace any faulty hoses with new ones.

    PCV Valve
    CARBURETED AND TFI ENGINES
    See Figure 2
    1. Detach the PCV hoses from the 3-way connection (1986-90 models), or from the rocker arm cover (1991-95 models).
    2.  
    3. Start the engine and allow it to idle.
    4.  
    5. Position your thumb over the end of the disconnected PCV valve hose, and check for vacuum.
    6.  
    7. If no vacuum is evident, check the hose for a clog or other obstruction. Replace the hose, if necessary.
    8.  
    9. Turn the engine off.
    10.  


    CAUTION
    NEVER suck air through the PCV valve. Residual toxic gasoline and blow-by fumes may be inhaled, which can cause severe internal injuries.



    Click image to see an enlarged view

    Fig. Fig. 2: The PCV valve is threaded into a boss in the intake manifold

    1. Disconnect the PCV valve hose from the valve. Attach a new hose to the valve, then blow air through the new hose and into the PCV valve. The air should pass with difficulty through the PCV valve (from the rocker arm side to the intake manifold side of the PCV valve).
    2.  
    3. If the air passes easily through the valve, it is stuck in the open position. Replace the valve with a new one.
    4.  
    5. If a new valve is to be installed, wrap Teflon® sealing tape around the PCV valve threads, then install it in the intake manifold.
    6.  
    7. Reattach all of the system hoses to the 3-way connection (1986-90 models only), the PCV valve, and to the rocker arm cover.
    8.  

    MFI ENGINES

    See Figures 3 and 4

    1. Remove the throttle cover from the engine.
    2.  
    3. Remove the PCV valve, with the hose attached, by pulling it out of the rocker arm cover.
    4.  
    5. Start the engine and allow it to idle.
    6.  
    7. Place the tip of one of your fingers over the exposed end of the PCV valve to feel for vacuum. If no vacuum is present, check the valve and hose for an obstruction or clogging; replace either component, if necessary.
    8.  



    Click image to see an enlarged view

    Fig. Fig. 3: The PCV valve is mounted in the rocker arm cover



    Click image to see an enlarged view

    Fig. Fig. 4: To inspect the PCV valve, remove it from the rocker arm cover and vacuum hose, then shake it and listen for a rattling sound

    1. Stop the engine.
    2.  
    3. Detach the valve from the hose, and shake it. Listen to valve, while shaking it, to check the needle inside; if the valve does not emit a rattling noise, replace it with a new one.
    4.  
    5. Reattach the hose to the valve, and insert the valve into the rocker arm cover grommet.
    6.  
    7. Install the throttle cover.
    8.  

    REMOVAL & INSTALLATION



    PCV Valve
    CARBURETED AND TFI ENGINES
    See Figure 2
    1. Detach the ventilation system hose from the PCV valve.
    2.  

    The PCV valve is threaded into the intake manifold.

    1. Using an open end wrench, or a socket and ratchet, remove the PCV valve from the intake manifold.
    2.  

    To install:
    1. If installing the old PCV valve, clean the threads.
    2.  
    3. Wrap Teflon® sealing tape around the valve threads.
    4.  
    5. Thread the valve into the intake manifold by hand, to avoid crossthreading it.
    6.  
    7. Tighten the valve to 133-221 inch lbs. (15-25 Nm).
    8.  
    9. Reattach the ventilation hose to the valve.
    10.  

    MFI ENGINES

    See Figure 3

    1. Remove the throttle cover from the engine.
    2.  
    3. Remove the PCV valve, with the hose attached, by pulling it out of the rocker arm cover.
    4.  
    5. Detach the valve from the hose.
    6.  

    To install:
    1. Attach the hose to the valve, and secure them with a hose clamp.
    2.  
    3. Insert the valve into the rocker arm cover grommet.
    4.  
    5. Install the throttle cover.
    6.  

     
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