VRV adjustment.

[towcat]

3.

Check adjustment of Vacuum Regulator Valve (VRV) (automatic transmissions only). Refer to Figures 22 and 23. On a 6.9L diesel engineequipped truck with C6 automatic transmission, a VRV provides a vacuum signal which is proportional to the throttle position, to the transmission vacuum diaphragm. To check the VRV for proper operation and adjustment, the engine must not be running.

Figure 22 - Article 87-10-21

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a.	Disconnect the two-port vacuum connector from the VRV located on the left side of fuel injection pump, Figure 22.
b.	Remove throttle cable from throttle lever on right side of fuel injection pump.
c.	Remove throttle return spring. Install end of spring over throttle lever ball stud and other end over throttle cable support bracket.
d.	Attach a vacuum pump with gauge to upper port of VRV (vacuum supply side).
e.	Attach a vacuum gauge to lower port of VRV (labeled TRANS on VRV).
f.	Apply 20 inches minimum of vacuum to VRV and maintain. It will be necessary to pump vacuum up as it bleeds off. CYCLE THROTTLE LEVER FIVE (5) TIMES FROM IDLE TO WIDE OPEN THROTTLE (WOT) WITH VACUUM APPLIED.

Figure 23 - Article 87-10-21

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Insert gauge block, T83T-7B200-AH (0.515 inch), between pump boss and throttle wide-open stop, Figure 23. The throttle return spring, as re-positioned in Step C. above, will hold throttle lever stop against gauge block.
THE VACUUM GAUGE ATTACHED TO LOWER PORT OF THE VRV SHOULD INDICATE 6-8 INCHES VACUUM. IF VACUUM READING IS WRONG, ADJUST VRV TO OBTAIN READING OF SEVEN (7) INCHES OF VACUUM.

g.	To adjust, loosen the two (2) screws that attach VRV to fuel injection pump, Figure 22. Rotate VRV until proper vacuum is obtained. When you get proper vacuum reading, tighten the two (2) screws to 75-90 in.lbs. (8-10.5 N-m). If VRV cannot be adjuted to get proper vacuum, replace the VRV and repeat this procedure starting at Step D.
h.	Remove gauge block.
i.	Reattach throttle return spring and throttle cable.
j.	Apply 20 inches of vacuum to the VRV and WHILE MAINTAINING VACUUM, CYCLE THROTTLE LEVER FROM IDLE TO WOT FIVE (5) TIMES. The vacuum gauge must indicate at least 13 inches with throttle at idle position. If vacuum gauge indicates less than 13 inches, the VRV must be replaced and the new VRV adjusted per the above procedure.
k.	After making the check or adjustment, remove vacuum pump and gauge from VRV and reattach vacuum connector.
l.	Start engine. Check throttle operation and check transmission shifts.

Correct VRV usage is necessary to be sure of proper vehicle and transmission performance. The current VRV usage (service) is as follows:

1983-86 model years E5TZ-7B200-A (green VRV cam) 1987 model year E7TZ-7B200-A (yellow VRV cam) The wrong adjustment, or the wrong VRV, can result in delayed or harsh shifts.

 

[towcat]

i posted this due to some questions on proper VRV adjustment. if not done properly, you can burn up a C6 trans easily.

 

[icanfixall]

Thanks for the information calvin. I never needed this but like to have the information anyway. I did know this adjustment was necessary to a proper running C6. Sure didn't know there were two differant VRV for the differant years. I try to "collect" those when I find them at the yards I visit. I think I have two yellow VRV but not sure. Might be just one. Had several of them just because they fit my pockets...

 

[towcat]

here's another description with better diagrams.

VACUUM REGULATOR VALVE ADJUST

NOTE: During the check and adjustment procedure, the engine must not be operating.

1. Disconnect two port vacuum connector from vacuum regulator valve located on the left side of the fuel injection pump.
2. Disconnect throttle cable from throttle lever.
3. Remove throttle return spring. Install end of spring over throttle lever ball stud and other end of spring over throttle cable support bracket.
4. Connect a suitable vacuum pump to the upper port of the vacuum regulator valve (vacuum supply side).
5. Connect a suitable vacuum gauge to lower port of vacuum regulator valve labeled TRANS.
6. Apply and maintain 20 in Hg of vacuum to the vacuum regulator valve. It will be necessary to pump the vacuum up as it bleeds off. Cycle the throttle lever 5 times from idle to the wide open throttle position with vacuum applied.

Vacuum Regulator Valve Gauge Block Installation

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1. Insert gauge block No. T83T-7B200-AH (0.515 in) between pump boss and throttle wide open stop. The throttle return spring as repositioned previously, will hold the throttle lever stop against the gauge block tool. The vacuum gauge should indicate 6-8 in Hg of vacuum. If reading obtained is not as specified, adjust vacuum regulator valve as follows:

• 1. Loosen two adjustment screws attaching vacuum regulator valve to the fuel injection pump.
  2. Rotate vacuum regulator valve until correct vacuum reading is obtained, then torque the two adjustment screws to 75-90 in lbs .
  3. If vacuum regulator valve cannot be adjusted, replace vacuum regulator valve and repeat adjustment procedure.
  4. Remove gauge block tool.
  5. Connect throttle return spring and throttle cable.
  6. Apply 20 in Hg of vacuum to the vacuum regulator valve and while maintaining vacuum, cycle throttle lever from idle to the wide open throttle position 5 times . The vacuum gauge should indicate at least 13 in Hg (throttle at idle position).
  7. If vacuum gauge indicates less than 13 in Hg the vacuum regulator valve must be replaced and the new valve adjusted.
  8. After necessary adjustment procedure has been completed, remove vacuum pump and gauge from vacuum regulator valve. Reconnect vacuum connector.
  9. Start engine and check operation of throttle. Check transmission shifts.

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