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05-02-2002, 08:18 PM
#1
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My key has started to hang up when I put it in the ignition -- it goes in about 90 % and stops. If i pull it out and rotate it 180 degrees it works fine. What's up with that? Is there a quick fix?
Next, the AC seems to have a mind of its own. I'll turn it on low and , for no reason, it will start to blow hard for a few seconds and the air seems to switch between vents randomly. Is it possessed? Please don't tell me it's the CCU.
Next, the AC seems to have a mind of its own. I'll turn it on low and , for no reason, it will start to blow hard for a few seconds and the air seems to switch between vents randomly. Is it possessed? Please don't tell me it's the CCU.
05-02-2002, 09:21 PM
#2
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Don't know about the key issue, but when the second CCU went out on my 964 C2 I had identical symptoms and a $1500.00 repair bill.....it was the same unit as used in 1994....don't know if it carried over to the early 993s....
05-03-2002, 12:04 AM
#3
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Don,
Sounds like you've got a tough one there. The shop manual contains detail on how to check the various servo-motors and blowers that make up the system. As Berkeley suggests, it could be your CCU, but you don't really know that until the motors/servos have been tested.
My knowledge of this system is limited (I'm learning as I type
), but it sounds like either one of your (left & right) mixing chamber servos could be sticking. And, your heater (left-hand) blower fan is deciding to kick into max-speed, as if you had pressed the max A/C button (which, to me, would suggest the CCU acting up).
Does your system only act up with the A/C. That is, no problems with the heat?
Below is a recent link on the HVAC system off the 964 board. May be of some use to you:
<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=4&t=001405" target="_blank">964 HVAC Link</a>
Finally, here is the text of an excellent e-mail thread on the HVAC system, information provided by Adrian Streather.
*******************
Dear Randall,
There are five servo valves,
2 one for each mixing chamber (mixes cool air with hot air to meet
temperature selection)
1 for fresh air supply (fresh air supply)
1 defrost flap (defrost directed to windshield)
1 footwell flap (air directed to your feet)
All five valves are fitted into the airconditioning and heating assembly at
the rear of the luggage compartment.
They are all Hella assemblies and the motors are manufactured in Hong Kong,
Ciao,
Adrian
911C4
PS: I have no idea about dates of publication etc yet. I am still writing
the book.
----- Original Message -----
From: "Randall Granaas" <rgranaas@flash.net>
To: <964porsche@smartgroups.com>
Sent: Tuesday, August 21, 2001 1:51 AM
Subject: Re: [964porsche] oil temperature/pressure
> Hi Adrian,
>
> Thanks for the wonderful information. Can you also give us the
CliffsNotes
> version of how many/where the HVAC servo motors are, and what they do?
>
> Looking forward to reading your book. Where do I buy an advanced copy
:-)?
>
> Randall g.
> Dana Point, CA.
>
> P.S. You guys do have CliffsNotes over in Europe, don't you?
>
> Adrian Streather wrote:
>
> > Dear Antony,
> > What do the fan do, well here we go. The short version.
> > LH Blower fan front, blows air into interior
> > RH Blower fan front, defrost function
> > Rear Blower fan has two functions,
> > Low speed, supplies hot air to the heating system
> > High speed, dumps hot air from pipes surrounding engine to cool engine
> > Condenser Fan, two speed fan, blows air through condenser to remove heat
> > from the high pressure high temperature refrigerant vapour to convert it
> > back to a low pressure, low temperature liquid.
> > Temp Sensor fan blows air over the temp sensor to provide accurate
> > temperature monitoring.
> > Oil Cooler Fan blows outside air through the oil cooler and this air
> > extracts the heat from the oil flowing through the oil cooler and the
now
> > hot air goes back into the atmosphere.
> > Ciao,
> > Adrian
> > 911C4
> >
> > PS: extended version is in my book.
> >
> > ----- Original Message -----
> > From: Antony Shine <antony@compwhse.demon.co.uk>
> > To: <964porsche@smartgroups.com>
> > Sent: Monday, August 20, 2001 9:07 AM
> > Subject: Re: [964porsche] oil temperature/pressure
> >
> > > Adrian,
> > >
> > > Forgive my naive question. I am a little confused.
> > >
> > > > Fans installed in the 964 series.
> > > > 3 Blower fans, 2 in the front, one in the rear
> > > > 1 Temp sensor fan
> > > > 1 Condenser fan
> > > > 1 Oil Cooler fan
> > >
> > > Could you explain, where they are and what they do for those of us who
are
> > > not as knowledgeable as the rest?
> > >
> > > Thanks
> > >
> > > Antony
> > >
Sounds like you've got a tough one there. The shop manual contains detail on how to check the various servo-motors and blowers that make up the system. As Berkeley suggests, it could be your CCU, but you don't really know that until the motors/servos have been tested.
My knowledge of this system is limited (I'm learning as I type
), but it sounds like either one of your (left & right) mixing chamber servos could be sticking. And, your heater (left-hand) blower fan is deciding to kick into max-speed, as if you had pressed the max A/C button (which, to me, would suggest the CCU acting up). Does your system only act up with the A/C. That is, no problems with the heat?
Below is a recent link on the HVAC system off the 964 board. May be of some use to you:
<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=4&t=001405" target="_blank">964 HVAC Link</a>
Finally, here is the text of an excellent e-mail thread on the HVAC system, information provided by Adrian Streather.
*******************
Dear Randall,
There are five servo valves,
2 one for each mixing chamber (mixes cool air with hot air to meet
temperature selection)
1 for fresh air supply (fresh air supply)
1 defrost flap (defrost directed to windshield)
1 footwell flap (air directed to your feet)
All five valves are fitted into the airconditioning and heating assembly at
the rear of the luggage compartment.
They are all Hella assemblies and the motors are manufactured in Hong Kong,
Ciao,
Adrian
911C4
PS: I have no idea about dates of publication etc yet. I am still writing
the book.
----- Original Message -----
From: "Randall Granaas" <rgranaas@flash.net>
To: <964porsche@smartgroups.com>
Sent: Tuesday, August 21, 2001 1:51 AM
Subject: Re: [964porsche] oil temperature/pressure
> Hi Adrian,
>
> Thanks for the wonderful information. Can you also give us the
CliffsNotes
> version of how many/where the HVAC servo motors are, and what they do?
>
> Looking forward to reading your book. Where do I buy an advanced copy
:-)?
>
> Randall g.
> Dana Point, CA.
>
> P.S. You guys do have CliffsNotes over in Europe, don't you?
>
> Adrian Streather wrote:
>
> > Dear Antony,
> > What do the fan do, well here we go. The short version.
> > LH Blower fan front, blows air into interior
> > RH Blower fan front, defrost function
> > Rear Blower fan has two functions,
> > Low speed, supplies hot air to the heating system
> > High speed, dumps hot air from pipes surrounding engine to cool engine
> > Condenser Fan, two speed fan, blows air through condenser to remove heat
> > from the high pressure high temperature refrigerant vapour to convert it
> > back to a low pressure, low temperature liquid.
> > Temp Sensor fan blows air over the temp sensor to provide accurate
> > temperature monitoring.
> > Oil Cooler Fan blows outside air through the oil cooler and this air
> > extracts the heat from the oil flowing through the oil cooler and the
now
> > hot air goes back into the atmosphere.
> > Ciao,
> > Adrian
> > 911C4
> >
> > PS: extended version is in my book.
> >
> > ----- Original Message -----
> > From: Antony Shine <antony@compwhse.demon.co.uk>
> > To: <964porsche@smartgroups.com>
> > Sent: Monday, August 20, 2001 9:07 AM
> > Subject: Re: [964porsche] oil temperature/pressure
> >
> > > Adrian,
> > >
> > > Forgive my naive question. I am a little confused.
> > >
> > > > Fans installed in the 964 series.
> > > > 3 Blower fans, 2 in the front, one in the rear
> > > > 1 Temp sensor fan
> > > > 1 Condenser fan
> > > > 1 Oil Cooler fan
> > >
> > > Could you explain, where they are and what they do for those of us who
are
> > > not as knowledgeable as the rest?
> > >
> > > Thanks
> > >
> > > Antony
> > >
05-03-2002, 12:12 AM
#4
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Hmmmm ... a simpler approach. Is your problem easily repeatable, that is, does it act up every time you turn on the A/C? If so .... any chance you know of a fellow 993 owner that might let you run their CCU long enough to see if the problem persists? If not, well .... suppose you're back into testing servos and motors. Or, just taking the car back to the shop. 
05-03-2002, 09:00 AM
#5
[quote]Originally posted by Randall G.:
<strong>Hmmmm ... a simpler approach. Is your problem easily repeatable, that is, does it act up every time you turn on the A/C? If so .... any chance you know of a fellow 993 owner that might let you run their CCU long enough to see if the problem persists? If not, well .... suppose you're back into testing servos and motors. Or, just taking the car back to the shop. </strong><hr></blockquote>
Be very careful if you do this !!!
As Berkley said, the 94 cars have a similar ccu to the 964s (may even be the same part number).
The wiring configuration on the connectors was changed when they did away with (or was it introduced ?) the vacuum controlled flap.
If you have a complete set of wiring diagrams for the various years you can check this if you wish.
The PET lists three variants, based on model year.
You must make sure you try the same number of ccu, or you may well destroy something.
HTH.
Cheers,
John (94 Iris Blue 993 C2)
<strong>Hmmmm ... a simpler approach. Is your problem easily repeatable, that is, does it act up every time you turn on the A/C? If so .... any chance you know of a fellow 993 owner that might let you run their CCU long enough to see if the problem persists? If not, well .... suppose you're back into testing servos and motors. Or, just taking the car back to the shop.
</strong><hr></blockquote>Be very careful if you do this !!!
As Berkley said, the 94 cars have a similar ccu to the 964s (may even be the same part number).
The wiring configuration on the connectors was changed when they did away with (or was it introduced ?) the vacuum controlled flap.
If you have a complete set of wiring diagrams for the various years you can check this if you wish.
The PET lists three variants, based on model year.
You must make sure you try the same number of ccu, or you may well destroy something.
HTH.
Cheers,
John (94 Iris Blue 993 C2)
05-03-2002, 11:02 AM
#6
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Randall, the problem is only with the AC, and is reoccuring. I cannot trigger it with any particular action. I can , however, stop it by hitting the recirculate switch! For some reason, the system operates fine in recirculate mode. I have had the car for several years and it has acted up since I bought it. Now I just run in the reciculate mode and don't worry about the malfuntion. I just thought I'd get a Rennlist consult to see if others had this problem and whether there was an easy solution.
05-03-2002, 11:30 AM
#7
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Hi Don,
When you say reoccurring, do you mean intermittent?
Recirc mode works fine? Wonder if your fresh air servo is acting up ... but, that should affect your heat, as well. <img src="confused.gif" border="0">
When you say reoccurring, do you mean intermittent?
Recirc mode works fine? Wonder if your fresh air servo is acting up ... but, that should affect your heat, as well. <img src="confused.gif" border="0">
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05-03-2002, 11:47 AM
#8
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[quote]Originally posted by John W:
<strong>
Be very careful if you do this !!!
As Berkley said, the 94 cars have a similar ccu to the 964s (may even be the same part number).
The wiring configuration on the connectors was changed when they did away with (or was it introduced ?) the vacuum controlled flap.
If you have a complete set of wiring diagrams for the various years you can check this if you wish.
The PET lists three variants, based on model year.
You must make sure you try the same number of ccu, or you may well destroy something.
HTH.
Cheers,
John (94 Iris Blue 993 C2)</strong><hr></blockquote>
Here's an excellent thread on CCU compatibility for the various 964/993 model years:
<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=4&t=000695" target="_blank">CCU Compatibility Thread</a>
Since Don lives in the U.S., he can't borrow a CCU from a '94 993 owner. The 95-98 model CCUs are the same part number. Expanding, Porsche currently sells only two CCU models .... one for 964s and one for 95-98 993s. At least that's the case in the U.S.
One more interesting tidbit. I was told by a few people that the "MAX AC" button wouldn't work on my '91 when I installed the updated 964 CCU. Turns out, it does everything the 993 Max A/C button does. Here's the pertinent thread:
<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=4&t=000749" target="_blank">Another CCU Thread</a>
<strong>
Be very careful if you do this !!!
As Berkley said, the 94 cars have a similar ccu to the 964s (may even be the same part number).
The wiring configuration on the connectors was changed when they did away with (or was it introduced ?) the vacuum controlled flap.
If you have a complete set of wiring diagrams for the various years you can check this if you wish.
The PET lists three variants, based on model year.
You must make sure you try the same number of ccu, or you may well destroy something.
HTH.
Cheers,
John (94 Iris Blue 993 C2)</strong><hr></blockquote>
Here's an excellent thread on CCU compatibility for the various 964/993 model years:
<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=4&t=000695" target="_blank">CCU Compatibility Thread</a>
Since Don lives in the U.S., he can't borrow a CCU from a '94 993 owner. The 95-98 model CCUs are the same part number. Expanding, Porsche currently sells only two CCU models .... one for 964s and one for 95-98 993s. At least that's the case in the U.S.
One more interesting tidbit. I was told by a few people that the "MAX AC" button wouldn't work on my '91 when I installed the updated 964 CCU. Turns out, it does everything the 993 Max A/C button does. Here's the pertinent thread:
<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=4&t=000749" target="_blank">Another CCU Thread</a>
05-03-2002, 11:48 AM
#9
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Yes. It seems as if the problem occurs most often when the air is first turned on, but it may just be that after it acts up, I switch to recirculate. I should also add that the system works fine when I just have the fan on, with no AC.
05-03-2002, 01:41 PM
#10
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Don, the A/C in my car does the same thing. It occasionally starts blowing harder at any given time; sometimes it's warmer when it does blow harder. It's almost like it has an "Automatic" setting that compensates for the inside temperature of the car. I think external temperature and maybe some other factors determine this. My '95 car did not do this, but I think as long as the A/C is effective, I'm not worrying about it. Yours may be more "extreme" than mine though.
FWIW...
FWIW...