See Figure 1
The operation of this system reduces the 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. This system is only applicable to the 1989-91 2VZ-FE engines.
- Warm up and stop engine.
- Check idle speed.
- Disconnect the throttle cables from the throttle cam.
- Remove the VTV cap, filter and separator from the dash pot.
Adjust DP setting speed as follows:
- Race the engine at 2500 rpm for a few seconds. Plug the VTV hole with your finger in the dash pot assembly.
- Release the throttle valve.
- Check the DP setting speed. The DP setting speed is 2000 rpm with cooling fan OFF.
- Adjust the DP setting speed by turning the DP adjusting screw.
- Reinstall the DP separator, filter and VTV cap.
- Connect the throttle cables to the throttle cam.
- Check system operation by racing the engine at 2500 rpm for a few seconds, release the throttle valve and check that the engine returns to idle speed in a few seconds.
REMOVAL & INSTALLATION
- To remove the dash pot assembly, unplug the vacuum hose then remove the dash pot mounting screws.
- Remove the assembly from the throttle body.
- Installation is the reverse of removal. Replace the dash pot assembly and adjust if necessary.