Dashpot Control System

Engine must be at normal operating temperature. Ensure idle speed is correct. Raise engine speed to 3000 RPM. Pinch vacuum hose between dashpot and Vacuum Transmitting Valve (VTV). See Fig 1. Release throttle valve. Ensure dashpot is set and engine is at 2000 RPM. To adjust dashpot idle speed, See Fig 2.
To check VTV, run engine at 3000 RPM. Pinch vacuum hose between VTV and dashpot. Release throttle. Release pinched hose. Engine should return to idle within about 1 second. To check VTV off of vehicle, See Fig 3.

DASHPOT TESTING RPM

Testing RPM

⁽¹⁾ Dashpot Setting RPM

3000

2000

⁽¹⁾	With cooling fan off.

Fig 1: Testing Dashpot System

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: Adjusting Dashpot Idle Speed

Fig 3: Testing Vacuum Transmitting Valve (VTV)