Chevrolet Blazer/Jimmy 1969-1982 Repair Guide

Transmission Vacuum Regulator Valve



  1. Attach the vacuum regulator valve snugly, but loosely, to the injection pump. The switch body must be free to rotate on the pump.
  3. Apply approximately 9-10 psi of vacuum to the inboard nipple. Attach a vacuum gauge to the outboard nipple.
  5. Insert a vacuum regulator valve gage bar between the gage boss on the injection pump and the wide open stop screw on the throttle lever.
  7. Rotate and hold the throttle shaft against the gage bar.
  9. Slowly rotate the vacuum regulator valve body clockwise (facing the valve) until the vacuum gauge reads 5.6 psi. Hold the valve at this position and tighten the mounting screws.

The valve must only be set while rotating in the clockwise direction.

  1. Check by releasing the throttle shaft and allowing it to return to the idle stop position. Rotate the throttle shaft back against the gage bar and check that the vacuum gauge still reads 5.6 psi. If not, the valve must be reset again.