Adjusting Boost Control Unit Operating Pressure
- Turn adjusting nut as necessary until operating pressure is obtained. See Fig 1. Turning adjusting nut clockwise decreases operating pressure and counterclockwise increases pressure.
- After setting pressure to specified range, accelerate engine and check adjustment. If lower than specified level, turn adjusting nut until specification is correct. Accelerate engine again and check adjustment. If engine speed cannot be decreased to idle when checking control unit operating pressure, proceed as follows:
- Turn adjusting nut counterclockwise so operating pressure is 0.98 in. Hg higher than specified, then turn adjusting nut clockwise so pressure drops to specification.
- If operating pressure cannot be observed in step 3), turn adjuster counterclockwise so operating pressure is 1.97 in. Hg higher than specified, then turn adjuster 1/2 turn clockwise so pressure drops to specifications.NOTE: The boost control unit operating pressure must be set to specifications after above 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. Ensure model numbers and identification marks match when replacing unit.