Positive Crankcase Ventilation (Pcv) System - Toyota Land Cruiser 1988 Repair Manual

EC-4 EMISSION CONTROl SYSTEMS- Positive Crankcase Ventilation (PCV) System
POSITIVE CRANKCASE VENTILATION (PCV) SYSTEM
- - Blow-by Gas
----- Fresh Air
EC3078
To reduce HC emissions, crankcase blow-by gas (HC) is routed through the PCV valve to the intake manifold
for combustion in the cylinders.
Engine not Running or Backfiring
Intake Manifold Side
• PCV VALVE IS CLOSED.
Cylinder Head Side
Idling or Decelerating
• PCV VALVE IS OPE
EC1007
• VACUUM PASSAGE IS SMALL.
EC1008
Normal Operation
• PCV VALVE IS OPEN.
• VACUUM PASSAGE IS
LARGE.
Acceleration or High Load
• PCV VALVE IS FULLY
OPEN.
EC1009
EC1010