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.



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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.



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