Adjusting BCDD Operating Pressure

Turn adjusting screw (810 models) or adjusting nut (280ZX) models as necessary until specified operating pressure is obtained. See Fig 2. Turning the adjusting mechanism clockwise decreases operating pressure and counterclockwise increases pressure.

NOTE: On 280ZX models, turn adjusting nut in or out with lock spring in place. Also, always set lock spring properly to prevent changes in operating pressure.

Fig 1: Schematic of Boost Controlled Deceleration Device System

Courtesy of NISSAN NORTH AMERICA, INC.

BCDD Operating Pressure (At Sea Level)

Application	Pressure (In. Hg)
280ZX	21.6-23.2
810	21.6-23.2

After setting pressure to specified range, accelerate engine and check adjustment. If lower than specified level, turn adjuster until specification is correct. Accelerate engine again and check adjustment. If engine speed cannot be decreased to idle when checking BCDD operating pressure, proceed as follows:
Turn adjuster counterclockwise, so BCDD operating pressure is 0.79 in. (20 mm) Hg higher than specification. Then turn adjuster 1/4 turn clockwise so pressure drops to specification.
If operating pressure cannot be observed in step 3), turn adjuster counterclockwise so BCDD operating pressure is 1.97 in. (50 mm) Hg higher than specification. Then turn adjuster 1/2 turn clockwise so pressure drops to specification.

Fig 2: Adjusting BCDD Operating Pressure
Courtesy of NISSAN NORTH AMERICA, INC.

NOTE: The BCDD operating pressure must be set to specifications after previous adjustment procedure, even if engine speed cannot be decreased to idling RPM.
If operating pressure cannot be adjusted, unit must be replaced as an assembly.