Maxima V6-2960cc 3.0L SOHC MFI (VG30E) (1990)
Swirl Control Valve: Description and Operation
Power Valve
CIRCUIT OPERATION
The power valve system is used to provide a variable length of intake run. When the engine is running at a low to medium rpm with a heavy load, the
ECU energizes the power valve solenoid. The solenoid allows manifold vacuum to act upon the power valve diaphragm, closing the power valve. This
increases the length of the intake runner which results in higher engine torque. A surge tank and one-way valve is provided to store vacuum so that the
valve will remain closed during low manifold vacuum conditions. When a longer intake run is not needed the power valve is left open to allow a shorter
air intake path. This results in improved engine performance in the higher rpm range.
Fig. 145 Vacuum Solenoid
POWER VALVE CONTROL SOLENOID
The ECU supplies the ground circuit to the solenoid. When the solenoid is energized a plunger is pulled, redirecting vacuum from the source and vent
port to the source and valve port allowing vacuum to be applied to the power valve diaphragm.
Fig. 75 Power Valve Operation
Refer to the figure for power valve operation.