1980 928 Climate Control advise or assistance request... | FerrariChat

1980 928 Climate Control advise or assistance request...

Discussion in 'Porsche' started by TTR, Jul 6, 2019.

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  1. TTR

    TTR F1 Veteran
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    Mar 29, 2007
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    Timo
    I don't often work on these or any other what I consider "late model" cars and would appreciate some solid advise.

    Started out diagnosing vacuum "leak", clearly audible behind the center console/dash.
    Ended up discovering several "issues" or problems related to A/C & Heater system controls, including couple of disconnected & 1 or 2 possibly mis-routed (vacuum) hoses behind the console, along with one bad/leaking actuator (for the re-circulating flap), etc.

    While the actuator replacement need is obvious, issues with the hoses were likely caused during aftermarket radio replacement, perhaps years ago, but unfortunately it seems Porsche (allegedly) didn't publish hose routing/vacuum operation schematics after 1979 (which I found and have a copy of). It also seems the entire vacuum control system had at least 2-3 changes/updates for 1980, including some hose color coding.

    So basically, I can probably reverse engineer the 1980 system vacuum schematics, but was wondering if someone out there has already done that and would be willing to share the info or can offer other relevant advise.

    TIA.
     
  2. TTR

    TTR F1 Veteran
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    No 928 experience or knowledge around here ?

    I know there are other forums/sites dedicated to Porsches, but some cursory views and searches around couple of those didn't yield anything helpful and I just didn't feel like registering to them.

    OTOH, I'm almost finished reverse engineering the system anyway with only couple of questionable issues and pretty sure I can figure them out, but if anyone already has answers... ?
     
  3. David_S

    David_S F1 World Champ
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    Can't guarantee it, but? I PROBABLY still have a copy of the 928 service manuals sitting around. Googling might find the same thing, but otherwise, might manage to find the right bits to scan & send to you.

    Otherwise?

    If you can get in contact with David (or Jeannie) Roberts, at 928 Specialists, they might get you the info you need quickly...

    https://928gt.com/
     
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  4. TTR

    TTR F1 Veteran
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    Thank you very much for your advise and offer to assist David.

    Your suggestion of manuals prompted me to recall that I have access to one of the oldest and largest factory literature inventories anywhere, located just few miles away from my shop and while I knew they don’t have much for Ferraris, I called and found out they do have a fairly large variety of OEM Porsche manuals, etc, so I’ll go tomorrow and check if they have anything useful.
    If not, I’ll try your suggestions.

    Thanks again.
    Timo
     
  5. SimCity3

    SimCity3 F1 Rookie

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  6. TTR

    TTR F1 Veteran
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    Thanks for suggestions.

    So far I managed to replace the broken actuator for recirculation air flap. OEM apparently is NLA, but I found new one from M-B, used in some their '80s/'90s models, and with some minor fabrications & modifications was able to adapt it for this application. It does not provide quite full flap opening, which could be achieved with more complex fabrication and modifications, but since it does fully close and opens up about +/- 85% of the original design as is, I believe it works adequately.

    As for the vacuum hose layout & routing schematics, my visit yesterday revealed that apparently only useful OEM published information regarding them relate to model years up to 1979 and then 1984 & later, but while 1980-1983 seem to have some component and design feature differences, non have been clearly (visually) noted in factory literature.

    Called 928gt.com and left a call back request.
    Would've done same with 928srus.com, but they don't appear to provide phone numbers.
    All else fails I might email them.

    And in worse case scenario, I'll just connect everything according to 1979 layout and add those not marked where I believe them to be most practical/useful.
     
  7. FiatRN

    FiatRN Formula Junior

    Nov 21, 2008
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    Jonathan Drout
    You need to join Rennlist and look at the 928 tech forum - there's loads of discussions, and lots of info about the 928 hvac system.

    https://rennlist.com/forums/928-forum-69/

    There is a good new-owner faq/sticky on that page that covers lots of info, contacts for parts, etc.

    Dwayne has a comprehensive write-up, but his is 1987 focused. I know there are differences, between your year and 87, but I don't know what they are. However, still worth a read:

    http://dwaynesgarage.norcal928.org/1987%20HVAC%20Vacuum%20Leak%20Testing%20and%20Repair%20Procedure.htm


    Roger at 928sR-US has a lame website, but is both knowledgeable and personable. It is best to call him to order parts, and not to use the website.
    928sRus.com 817-430-2688
    Roger can get you all the actuators.


    The basics - the system pulls vacuum from the engine bay, just in front of the brake booster. Then each actuator is controlled by solenoid. the solenoids live near your right calf. That's the place to test each vacuum line and actuator from. If any ONE actuator leaks, then the entire system fails to work properly. An intermittant leak can cause things to cycle open and closed. A full leak defaults the system. The heater valve defaults to full-hot when the system loses vacuum. The rest of the system defaults to defrost when vacuum is lost. This is great if something goes wrong while driving in the mountains in winter, but otherwise can result in a sauna that melts your face.
     
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  8. TTR

    TTR F1 Veteran
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    Thank you for taking time with extended response and I apologize for not replying to it sooner.

    I managed to figure this out on my own earlier, but took a cursory look at suggested “Dwayne” thread, which while quite informative, well explained and photo documented, didn’t directly address issues I had faced with this 1980 example.

    Thanks again to all that offered suggestions.
     
  9. TTR

    TTR F1 Veteran
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    Just to recap, I got it all sorted (by reverse engineering, using '79 vacuum diagram and '80 Owners Manual) and now "road" tested (everything work as it should and no vacuum leaks). :)
     
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  10. mello

    mello F1 Veteran
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    Nice! Can you post the vacuum diagram by chance? I have an '78 that's having issues. Thanks!
     
  11. TTR

    TTR F1 Veteran
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    Here’s a copy of what I found for ‘79 and earlier models.
    It has several differences with the system I just finished working on, but it was helpful and I used it as a base to re-draw my own schematic for the ‘80.
    I also saw a “layout” schematic for ‘84 and later, but it appeared less useful than this for ‘80 application.
    Image Unavailable, Please Login
     
  12. mello

    mello F1 Veteran
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    Thank you, I appreciate your contribution to this forum!
     
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