Accord Coupe L4-2.2L SOHC VTEC (1995)
Positive Crankcase Ventilation Valve: Description and Operation
PURPOSE
The Positive Crankcase Ventilation (PCV) Valve, located top of valve cover, meters air flow in the system at a rate that depends on manifold
vacuum. The function of the PCV valve is to restrict the flow of crankcase emissions when vacuum is high to preserve idle stability.
OPERATION
During partial throttle opening, manifold vacuum draws fresh air through the PCV valve into the intake air stream. During low vacuum conditions
(full throttle or heavy engine load) the manifold vacuum is insufficient to draw the gases through the valve, so gases flow in the reverse direction,
being drawn into the air cleaner and then into the intake air stream. On engines with excessive blow-by, some of the gases will flow into the air
cleaner under all conditions.