A/C Idle Adjustment

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Date: Wed, 23 Jul 1997 13:16:04 -0500
From: "Dean Hufstedler" 
Subject: Air conditioning
To: 

We just got the a/c going on my 1984 SR5 Xtracab 4X4.  It works great, but
when the compressor came on the engine revved to 2200.  We found the vacuum
throttle controller, but when we turned the throttle down, the compressor
went off and won't come on unless I turn it back up to about 1800 rpm.

What gives?

Huffy

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Date: Wed, 23 Jul 1997 14:43:39 -0400
From: Ed Ruf 
Subject: Air conditioning
To: Toy4x4@tlca.org

You need to adjust the A/C amplifier potentiometer. This sets the speed
below which the a/c clutch de-energized. It's located behind the glovebox.
Just unsnap the fabric between the box and the dash and look up towards the
left. You should be able to see the small circular recess for access to the
adjustment screw/pot.

Ed

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Date: Thu, 17 Jul 1997 18:33:49 -0400
From: Ed Ruf 
Subject: Air conditioning
To: Toy4x4@tlca.org

On 03:18 PM 7/17/97 -0700, Leroy Andersen wrote:
>I know the topic of A/C was bantered about a couple weeks ago, but I 
>either don't remember part of it, or my specific problem wasn't 
>discussed. My A/C works great as long as I am driving down the road. 
>When I come to a red light I notice that when I'm sitting there, the 
>A/C isn't blowing as cold. I finally figured out that if I give it a 
>little gas to raise the RPM, I hear a little 'click' behind the glovebox
>and the air gets colder again. I vaguely remember some discussion about 
>an adjustment that can be made back in there so that if the engine RPM 
>drops, the compressor doesn't kick off. I'm sure one of you A/C gurus 
>out there can help me here??

Not an A/C guru, just a DSE (Dumb Sh*t Engineer, it's a long story, but I
once worked with a bunch of PhD physicists!) that's been there and done
that. If you unsnap the fabric from the back of the glovebox (no need to
remove it) on the upper left you should find the A/C amplifier. The
amplifier has two functions: 1) comparing compressor and engine rpm and
de-energizing the compressor clutch if they are not the same; and 2) has an
engine rpm setpoint below which the clutch is de-energized. The second
function is what's getting you. There's a small adjustment screw on the
front (all black) to set this. Start the truck, turn the A/C on and adjust
the amplifier.

BTW, the ASSUMES the VSV which raises the idle speed when you turn the A/C
on is functioning properly. If you switch the A/C on and your idle speed
doesn't increase, then this VSV is bad and needs to be replaced. 

Ed Ruf  (egruf@visi.net) or for Scramjet related ? (e.g.ruf@larc.nasa.gov)
86 Toy 4x4 SR5 PU@126K, 3.5" Rcho susp.+RS-7ks,31x10.5 BFG-A/T,K&N
87 Toyota SR5 4Runner @118K, KYB GasSprings, 30.5x9.50 Cooper Disc.
86 Yamaha FJ-1200SC @ 16K 
82 Honda XL600R Thunderin' Thumper
2.5 yr old, 110#, pure bred white GSD, Kaiser Klaus III, AKC# DL569628/04

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Date: 17 Jul 1997 15:39:17 -0700
From: "Jay Kopycinski" 
Subject: Air conditioning
To: "Toyota 4x4 List" 

                      Subject:                              Time:  3:39 PM
  OFFICE MEMO         Air conditioning                      Date:  7/17/97

I'm no guru, but on the ac evaporator box (big black one) under the dash
there is a small pocket (at least on '85s) that holds the ac amplifier
circuit card. On it is a small potentiometer that you can turn to adjust 
the engine rpm where the ac compressor cuts in and out.

______________________________________________
Jay Kopycinski                              '85 Toylet   (ROKTOY)
Gilbert, AZ                                    '85 4Runner (her project)
ryna10@email.sps.mot.com           '91 4Runner (for sale)
http://www.netzone.com/~jayk
Arizona Lo-Rangers 4WD Club            TLCA #3243
______________________________________________

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Date: Thu, 17 Jul 1997 20:20:06 -0400
From: Ed Ruf 
Subject: Air conditioning
To: Toy4x4@tlca.org

Sorry for not being absolutely clear. The pot on the amplifier is the
cutoff setting.  The fast idle speed believe is set with the big white knob
on the vacuum fitting coming off the middle of the intake plenum.

Ed

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Date: Thu, 17 Jul 1997 21:32:24 -0500
From: Steve Capuano 
Subject: Air conditioning
To: Toy4x4@tlca.org

You can make the compressor run continuosly, but if it spins too slow (like
what your fixin to do) you are not doing anything as far as cooling goes
just bogging the motor down.  you need the RPMs to keep the ref. flowing and
your pressures up.  Keep that in mind.  It may work, but it may not be
designed to be effective at that slow of a speed.


Steve Capuano			1996 Tacoma ext cab V6 4X4
capuano@hypercon.com		31x10.50x15 Wrangler RT/S
				Rear LockRight  K&N filter
NRA lifetime member		Dynomax 2.5" cat back  Synthetic all around

Headers are next on my list.  Oh also a free flow cat!

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Date: Mon, 17 Jul 1995 23:25:17 -0700
From: Leroy Andersen 
Subject: Air conditioning
To: Toy4x4@tlca.org

Actually, I'm not trying to get it to run at 700 RPM, I just don't want it
to kick off when I'm sitting at a light idling at around 900 to 1000 RPM. I
meant that if I set it at 700, then since the truck idles at 900-1000 it
would never shut off.
~~~
Leroy Andersen			1985 SR5 Short Bed 4x4/22RE
Citrus Heights, CA		138K Miles, RS9000's, 4.10's
andrsen@ns.net			Rancho Springs/Add-a-leaf
http://www.ns.net/~andrsen/

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Date: Mon, 28 Jul 1997 16:46:37 -0400
From: "Lang, David V." 
Subject: A/C Amplifier
To: "'Toy4x4@tlca.org'" 

I am having the same porblem with the A/C on my 88 4Runner. The
compressor shuts off when idling. Since I don't have an RPM gauge, do I
adjust by ear, is there a limit as to how low you can set the RPM's for
the compressor to kick on????

Thanks



David Lang
Information Services 
(602)301-4683
Email:   lang.david@mayo.edu

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Date: Mon, 28 Jul 1997 17:23:39 -0400
From: Ed Ruf 
Subject: A/C Amplifier
To: Toy4x4@tlca.org

Well I can tell you I set mine for 850 rpm until I got the new VSV
in. The A/C doesn't work as well at this low an rpm, but it's still
better than off. 

Ed, here in SE VA sweating up a storm.... 98F + humid = 108 heat index

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