tonic
Totally Hooked
- Aug 31, 2023
- 184
- 577
You are absolutely correctDoes anyone know why the noise is different in cold start in addition to the higher engine revs? In other cars I only noticed the high revs, but in the Yaris it almost seems like there is a valve open that makes it make noise... and with the modified exhaust it is more noticeable.... does it open the wastegate by any chance?!
From the service manual:
Wastegate Valve Control
During Engine Start
The ECM controls the vacuum regulating valve assembly to control the vacuum from the vacuum pump assembly to the actuator and open the wastegate valve. As a result, high temperature exhaust gases are supplied for the catalyst and warm-up time has been reduced.
