Vacuum Regulator Valve
The vacuum regulator valve provides vacuum signals to control automatic transmission shift points. Vacuum setting of valve should be checked and adjusted periodically, using the following procedure. Engine MUST NOT be running during this procedure.
- Loosen vacuum regulator valve so it is free to rotate on pump. Attach a hand-held vacuum pump and apply 20 in. Hg. vacuum to bottom port of valve. Attach vacuum gauge to top port of valve.
- Insert Gauge Block (J-33043-A) between gauge boss on injection pump and wide open stop screw on throttle lever (switch on position). See Fig 1.NOTE: Always refer to Emission Control Label for correct gauge block size.
- Rotate and hold throttle shaft against gauging block. Slowly rotate vacuum regulator valve body clockwise (facing valve) until vacuum gauge reads 10.9-12.1 in. Hg. Hold valve body at this position and tighten mounting screws.
- Check adjustment by allowing throttle shaft to return to idle stop position. Then rotate throttle shaft back against gauging block. Vacuum gauge reading must be within 10.9-12.1 in. Hg. If vacuum is outside limits, reset valve.
- With valve vacuum set, confirm detent switch point by reading resistance between Ignition (Pink with Black stripe wire) and Detent (Orange wire). Insert Switch Gauge (J-36142) between wide open stop pin and wide open stop screw on throttle lever. See Fig 1.
- Rotate throttle lever against switch gauge. There should be infinite resistance. Release throttle lever and remove gauge. Rotate throttle lever to wide open throttle (lever stop screw touching pump stop pin).
- Check switch for continuity. Switch must have zero to one ohms continuity before throttle reaches wide open position. If switch does not meet these specifications, reset assembly by returning to step 1) and repeating entire procedure.