Dash Pot (Dp) System - Toyota Land Cruiser 1988 Repair Manual

EMISSION CONTROL SYSTEMS- Dash Pot (DP) System EC-9
DASH POT (DP) SYSTEM
Dash Pot
EC2725
Normal Driving Deceleration
VTV
EC2733 EC2732
To reduce HC and CO emissions, when decelerating the dash pot opens the throttle valve slightly more than
at idle. This causes the air-fuel mixture to burn completely.
Condition Diaphragm VTV Throttle Valve
Idling
Pushed in by return force of throttle
CLOSED
Idle speed position
valve
Normal driving Pushed out by diaphragm spring OPEN High speed position
Deceleration
Pushed in by return force of throttle
CLOSED
Slightly opens and then slowly closes
valve to idle position