Join Date: Nov 2001
Location: Western Australia (Perth)
Intake runner control,
The bible quotes:
In normal operation, below 3,800RPM the butterfly valvues are closed, causing the intake air to follow the longer path into the engine. At higher speeds, above 3,800RPM, the butterfly valves open allowing the intake air to follow a shorter path into the enging.
A vacuum actuator operates the butterfly valves. The PCM controls vacuum to the actuator via a solenoid valve. (I would say on and off)
Hope this helps.