Weird A/C behavior

[Larry C Leung]

Hmmm, I like the Zip tie idea. I do know my system seems to behave like
yours, although I haven't
tried the Hi setting yet. I am asking the list for the P/N for the weird
(compared to Pep Boys)
check valves (there are two). I figure, they're easy to get to, why not
try them. With the concept
that going into a low vacuum (throttle open) mode drops the center vents,
it seems like a likely
suspect. I don't (yet) own a mity-vac, and it's toooooo damn hot to
bother searching around under
the dash.

LL-NY


On Sun, 18 Aug 2002 11:06:02 -0400 "Doyt W. Echelberger"
<Doyt at buckeye-express.com> writes:
> Hello Larry.....I just got home from a long trip and have some
> additional
> peculiar A/C behavior to report.
>
> Bentley indicates that the dash vents are programmed to be closed on
>
> AUTO-HIGH explains why they don't blow when I expect them to.  I'm
> going to
> keep the fan speed setting on LOW when I use AUTO, and see if the
> center
> vents come on any sooner.
>
> There is a discrepancy between what the system is designed to do
> according
> to Bentley, and what it does in my 15 year old car.
>
> On my trip, I had the system set at AUTO-HIGH, and after about an
> hour of
> driving suddenly it was blowing cold air through the dash vents. And
> that
> isn't suppose to happen. Bentley sez they are suppose to be closed
> at the
> high fan setting, but open on low fan.
>
> When I shut the engine down at a rest stop and restarted it, the
> dash vents
> stayed closed at the same high fan setting for another hour, while
> the
> system blew through the defrost and foot vents,   and then the dash
> vents
> opened up about half way all by themselves....not all the way. It
> was like
> it was set on BI-LEVEL.
>
> Getting to a solution.....Eric Kissel reports that he placed a zip
> tie to
> keep the dash vents open. (I'm uninformed about where all these
> flaps are
> located and accessed.)
>
> My 86-88 5k Bentley shows a diagram at 87.128  and another at 87.174
>  and
> 87.175
>
> I'm considering the zip tie solution, and I am wondering if I should
> be
> reclining upside down under the dash in the passenger front, or
> peering
> down into the air conditioner bay from the outside of the car, with
> the
> plastic rain shield cover off, to do the zip tie trick. Need some
> basic
> direction.
>
> Thought you might be interested in how this is developing.
>
> Doyt Echelberger
> 87 5ktq in Ohio   USA
>
>  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>.
> At 08:26 AM 8/16/2002 -0400, Kneale wrote:
> That vacuum servo in the evaporator box only adjusts the amount of
> air
> going into the HVAC system from either outside or inside the cabin.
> I
> suppose if the vacuum leaked there, it could reduce vacuum available
> to run
> the other parts of the system.  But if the servo is just moving
> itself
> because it's detached, I wouldn't think it would have any effect on
> which
> course the air took subsequently in the system.  That's managed by
> the
> heater core box flap controls and the servo motors under the dash
> behind
> the radio, I think.
>
> At 07:16 AM 08/16/2002 -0400, Doyt W. Echelberger wrote:
>
> When I took a few hours to clean out the leaves (by opening the
> under-dash
> hinged door behind the glove box) I found the hose to the vacuum
> solenoid
> disconnected and dangling, and the solenoid was loose in it's
> plastic
> support cage. I used epoxy to attach the solenoid to it's cage and
> to hold
> the hose to the solenoid. This fix didn't change anything in the way
> it
> worked, so I'm going to go back under with a flashlight and see if I
> have
> any new insights while upside down, curled up like a pretzel. And
> I'll try
> the "Econ" and letting up on the throttle trick. Be assured, you
> will all
> hear of any success.
>
> Let's stay with this until we get it working right.  Thankfully, the
>
> default position does cool the cabin fairly well on my car, most of
> the time.
>
> Doyt Echelberger
> 87 5ktq in hot and humid Ohio
>
>  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> At 05:09 AM 8/16/2002 -0400, Larry Leung wrote:
> Paul, Doyt,
>
> I have a combination of your problems. I have the ability to get
> cooled
> air through the dash vents,
> but after awhile it blows out the defroster and floor (though not
> too
> strongly). I have found two things
> restore things to the dash (basically Paul's trick, turn the CC to
> ECON,
> back off the throttle (raise the
> vacuum), air out the dash vents again, turn back to A/C), or raise
> the
> set temperature to the point the
> fan doesn't run at full speed. I BELIEVE that it's a vacuum
> problem,
> however I have yet to trace all the
> leaks in the car's system (i.e. I don't quite pass the dipstick
> test) so
> I'm not sure. Perhaps it's a leaking
> servo under the dash. The problem is it's WAY too hot to work on the
> car,
> especially under the dash
> under the greenhouse in the hot sun. Ugh. Anyone have any other
> ideas?
>
> LL - NY       l.leung at juno.com
>
>
>  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>
>  > Date: Thu, 15 Aug 2002 22:38:31 -0400
>  > To: "Paul R. Luevano" <paul at clarity.net>
>  > From: "Doyt W. Echelberger" <Doyt at buckeye-express.com>
>  > Subject: Re: Weird AC Behavior
>  > Cc: quattro at audifans.com
>  >
>  > Paul, it does my heart good to read your story.  The A/C of my
> 87
>  > 5ktq has
>  > been doing that with increasing frequency for the past two
> years.
>  > This
>  > summer it has gotten to where it almost never blows out the dash
>  > vents when
>  > set on "Auto."
> .......................snip.............................
>  > Check out Scott's stuff at the address below and let me know if
> you
>  > can
>  > make yours work.
>  >
>  > http://www.sjmautotechnik.com/AC.html#recirc
>  >
>
>  >Doyt at buckeye-express.com>
>
>  >  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>  > At 08:45 PM 8/15/2002 -0400, Paul wrote wrote:
>  > >OK, so it has been hot .............snip...............
>  > >
>  > >Over the last few days, I have observed a very weird
> occurrence.
>  > When set to
>  > >"Auto" the AC will stop blowing from the dash vents.  This can
>  > happen after
>  > >several minutes or after just a few seconds.  It seems to blow
> out
>  > of the
>  > >defrost vents, but very weakly. Here is the weird part, if I
> switch
>  > it to
>  > >"Econ", it blows out of the dash vents with a vengeance.  I can
>  > then
>  > >switch back
>  > >to "Auto" and it will repeat, lasting from several seconds to
>  > several minutes.
>  >                       paul at clarity.net
>
>
>
>
>