Digital Climate Control Repair

  • #1

    Digital Climate Control Repair

    Having an issue with my climate control. I think it was related to the vacuum/climate control canister near the front of the car in the engine compartment. The canister that came with the car had the watercock/solenoid nipple, the nipple going to the firewall, and the nipple going to the intake. The intake vacuum line was teed off at the intake manifold, going one direction to the cruise control, and one direction to the vacuum canister. With this canister I wasn't getting any doors opening or cold air to enter the cabin, only getting hot air through the defroster…

    Then I went and grabbed what I could from a local salvage yard, another canister from an older model Z. This one instead of having the three lines mine had, it had an extra nipple for the climate control. I plugged this in and I could not feel vacuum from the port that goes thru the firewall just like my old canister. I got plenty of vaccuum from the cruise control nipple. So tested the vacuum by instead of attaching the firewall line to the firewall nipple I attached it to the cruise control nipple. Now whenever I hit the digital AC button I could see ventilator door open(dash is off) and a lot of cold air rushed inside. However when driving the door would close and I would get hot air upon accelleration.

    So I'm kind of confused what is wrong here, I think perhaps both canisters aren't the right one for my car, that maybe the PO used a canister off a manual climate control system. Sorry for the poor explanation here, but does anyone have any insight of what to look for or what may be going on here? I have looked online, looked at the Chilton's manual and the Field Service Manual. I would think the whole problem is with this vacuum canister and not something inside the car because IF I do get vacuum the doors work, unless I accellerate.
  • #2
    When you accelerate you lose vacuum to the AC components. The repairs are pretty well documented if you search, BUT it isn't something that ever goes away (unless you hook up a vac pump).
    Feedback- viewtopic.php?f=18&t=19840
  • #3
    Canister aside, the actuators that control the vent doors have rubber bladders that are often dry rotted or cracked and will fail under acceleration causing the doors to move because the actuator can't hold the vac. I ripped out my dash to get to the actuators behind the unit and replaced them which fixed the issue for me. Most if not all of those vac actuators are NLA but I've found there are a couple Ford actuators that will work with slight modification. Others have tried products like FlexSeal in attempt to seal the cracked rubber bladder in the actuator with good results (fyi, fix-a-flat doesn't do that good a job).
  • #4
    I know this is an older thread, but I am having similar issues. Under heavy acceleration, my AC goes to the defrost vent and I get hot air from them. I replaced all the Vac lines on the tank and am now starting to suspect the actuators and vac lines in the cabin. If I can't find actuators, how well does FlexSeal work?

    Additionally, I am pretty sure the lines coming off the Vacuum tank were not on there right. My car is an N/A 84 GLL and the lines were not hooked up like the one in this picture: http://www.88hybrid.com/vaclines/vaclines.htm I know that is from an 85 turbo, but the setup should be the same with the exception of the cruise control line, right?

    When I got the car, the line to the cabin was hooked to where the cruise line is on the pic from 88hybrid.com. The line from the plenum was in the one marked thru firewall and there was a cap on the one marked intake collector.

    I have moved the one from the plenum to the spot on the picture, capped the one marked thru firewall, and have the one going to the cabin in the one for the cruise. The cabin line was replaced with silicone hose and is in the cruise spot because the wall of the hose is too thick to go on the other spots due to a collar around the ports. I will probably run another line of standard vac hose from the cabin and hook it up like in the photo. I am unsure how much of a difference this will make. If anyone has any insight, I would appreciate it.
  • #5
    I won't pretend to be able to help with the hose routing as I don't have an NA and all I would do is look at the FSM and compare… but as far as using FlexSeal, what other option do you have? Those vacuum actuators are no longer available, and I wouldn't suggest buying those used. Depending on which one is bad you may be able to retro fit something to get it to work. I was able to use a new Ford part from a mustang to fix mine but I would imagine FlexSeal would work to seal a leaky bladder in the actuator.
  • #6
    I had this problem in my 85 gll. The port on the tank that says firewall should indeed run to the inside of cabin. Cap the one for cruise control. I have tested that my vacuum tank does indeed hold vacuum bit the check valve that's supposed to be internal to the tank had fail3d. So by adding an external vacuum one way check valve between the intake manifold port and vacuum tank, the problem is solved. Of course this means nothing if there are vacuum leaks on the inside of your car ( old vacuum lines or broken vacuum solenoids Or actuator diaphragms.
    http://z31performance.com/showthread…2-2-(-now-NA2T
    My build thread (:
  • #7
    if you search you will find several write ups to deal with this problem, use Google to look for Z31 vacuum lines diagram



    1988 300ZX Turbo, Shiro Special #760
    1988 300ZX Turbo Automatic (wife's car)
    1991 Hard-body 2WD

    http://zccw.org/zccw/?page_id=1215