4 Runner 2WD V6-180.5 2959cc 3.0L SOHC (3VZ-E) (1992)
Dashpot: Description and Operation
Fig. 43 Dash Pot System
Fig. 44 Dash Pot System Schematic
PURPOSE
The dash pot reduces hydrocarbons (HC) and carbon monoxide emissions by returning the throttle plate slowly to the idle position during
deceleration. This allows the air fuel mixture to burn more completely than if the throttle were closed abruptly.
OPERATION
The dash pot consists of a spring loaded diaphragm that extends when the throttle is opened, thus drawing in air through suction. The air becomes
trapped by the vacuum transmitting valve (VTV) and becomes a buffer on the diaphragm. When the throttle valve is released and comes in
contact with the DP actuator pin, the air is forced back out of the VTV filter slowly, returning the throttle valve slowly to its idle position.