NSX V6-3.0L DOHC (1991)
Fast Idle Valve: Description and Operation
Fast Idle Valve
The fast idle valve supplies additional intake air to increase idle speed during warm-up. It is located at the left rear of the intake manifold assembly next
to the throttle body.
When engine coolant temperature is below 86 degrees F (30 degrees C), the valve opens and bypasses additional air to the intake manifold.
The bypass valve is mechanically controlled by a thermo-wax plunger. When the engine is cold, the coolant surrounding the thermo-wax contracts the
plunger allowing additional air into the intake manifold. As the coolant temperature increases, the thermo-wax expands and the plunger closes off bypass
air.
