Honda Acura NSX 1991 Service Manual page 417

As the engine turns, the oil pump also starts to operate. Automatic transmission fluid is drawn from (99) and discharged
into (1). Then, ATF pressure is controled by the regulator valve and becomes line pressure (1). The torque converter
inlet pressure (I) enters (94) of torque converter through the orifice and discharges into (90).
The torque converter check valve prevents the torque converter pressure from falling.
Under this condition, the hydraulic pressure is not applied to the clutches.
(cont'd)