Dash Pot (Dp) System - Toyota Supra 1990 Manual

EC-8
EMISSION CONTROL SYSTEMS - Dash Pot (DP) System
DASH POT (DP) SYSTEM
7M-GE
7M-GTE
Air Filter
EC3317 EC3318
Normal Driving Deceleration
VTV VTV
DP Diaphragm DP Diaphragm
EC3440 EC3439
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