1995 R134a air-condition malfunction

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Old 14 Aug 2006, 08:21 pm   #1 (permalink)
Pszemol
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Default 1995 R134a air-condition malfunction

Hi,
have my camry air-condition compressor shutting off
itself occasionally. Then turning itself back on...

Probably due to some shut-off switch - the lamp on
the a/c button blinks. Is there a way to tell which
switch caused the compressor shut down ?

I have tested pressures with gauges and got about 20psi
on the low side - sometimes dropping to 10psi on cold
system and above 150psi on the high side...
I feel it is little bit too low on both sides, but
not sure. What is the proper pressure for that camry?

I see some bubbles in the sight glass, but I remember
seeing them even when the system was fully charged
and was working very efficiently blowing 40F air.

Now it is still cooling when compressor is on, but
not so good - the vents are blowing about 60F air...

Also noticed that on previous service belts were
exchanged and the alternator/compressor belt was
streached to hard, causing the compressor wheel to
turn slightly even when the compressor clutch was
not engaged. I made this belt little bit more loose
but the compressor still shuts off itself...

Any diagnostic advice appreciated!
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Old 15 Aug 2006, 01:00 am   #2 (permalink)
johngdole@hotmail.com
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Default Re: 1995 R134a air-condition malfunction

20psi is too low. Check the freon level. Are you getting bubbles in the
sight glass?

Pszemol wrote:
> Hi,
> have my camry air-condition compressor shutting off
> itself occasionally. Then turning itself back on...
>
> Probably due to some shut-off switch - the lamp on
> the a/c button blinks. Is there a way to tell which
> switch caused the compressor shut down ?
>
> I have tested pressures with gauges and got about 20psi
> on the low side - sometimes dropping to 10psi on cold
> system and above 150psi on the high side...
> I feel it is little bit too low on both sides, but
> not sure. What is the proper pressure for that camry?
>
> I see some bubbles in the sight glass, but I remember
> seeing them even when the system was fully charged
> and was working very efficiently blowing 40F air.
>
> Now it is still cooling when compressor is on, but
> not so good - the vents are blowing about 60F air...
>
> Also noticed that on previous service belts were
> exchanged and the alternator/compressor belt was
> streached to hard, causing the compressor wheel to
> turn slightly even when the compressor clutch was
> not engaged. I made this belt little bit more loose
> but the compressor still shuts off itself...
>
> Any diagnostic advice appreciated!


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Old 15 Aug 2006, 07:38 am   #3 (permalink)
Pszemol
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Default Re: 1995 R134a air-condition malfunction

<johngdole@hotmail.com> wrote in message news:1155621603.844141.302590@i3g2000cwc.googlegro ups.com...
> 20psi is too low. Check the freon level. Are you getting bubbles in the
> sight glass?


Yes, I was... Yesterday evening I got one 12oz can of freon.
Tried to recharge gas, but it went very slow... Could not
fit the whole can. The pressure rise to 26/205 - temperature
is back to <40F. Will see if the system will keep shutting off.
BTW - I see the bubbles in the sight glass anyway...

How long does it normalny take to suck all the gas from
one can? I waited about 10-15 minutes and I could still
feel the fluid in the can. Turned the valve back on and
stopped the process before the can was emptied...
Could not wait any longer
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Old 15 Aug 2006, 11:16 pm   #4 (permalink)
johngdole@hotmail.com
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Default Re: 1995 R134a air-condition malfunction

You don't want to put too much freon into the system. I had my at
35/230, at the upper range, during 90F outside air temp.

Sometimes extremely low low-side pressure is because the expansion
valve is stuck and the compressor will cycle on and off all the time.
But from the looks of 205 that's not the case.

Most of the time I charge a few ozs, never charged more than 6oz or 1/2
a can for a long time. There will always be some left because the low
side never gets below say 25-30PSI. It would start fast and then slow
down quickly. It helps to wrap a warm towel around it. It will also
help if someone revs the engine at 1500 rpm. That should be where you
check the pressures anyway (do check the rev specs for 95!).


Pszemol wrote:
> <johngdole@hotmail.com> wrote in message news:1155621603.844141.302590@i3g2000cwc.googlegro ups.com...
> > 20psi is too low. Check the freon level. Are you getting bubbles in the
> > sight glass?

>
> Yes, I was... Yesterday evening I got one 12oz can of freon.
> Tried to recharge gas, but it went very slow... Could not
> fit the whole can. The pressure rise to 26/205 - temperature
> is back to <40F. Will see if the system will keep shutting off.
> BTW - I see the bubbles in the sight glass anyway...
>
> How long does it normalny take to suck all the gas from
> one can? I waited about 10-15 minutes and I could still
> feel the fluid in the can. Turned the valve back on and
> stopped the process before the can was emptied...
> Could not wait any longer


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Old 16 Aug 2006, 11:01 am   #5 (permalink)
Pszemol
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Default Re: 1995 R134a air-condition malfunction

<johngdole@hotmail.com> wrote in message news:1155701805.469106.246450@m79g2000cwm.googlegr oups.com...
> You don't want to put too much freon into the system. I had my at
> 35/230, at the upper range, during 90F outside air temp.


So I have still room to put more.
BTW-I still see the bubbles in the sight glass.

> Sometimes extremely low low-side pressure is because the expansion
> valve is stuck and the compressor will cycle on and off all the time.
> But from the looks of 205 that's not the case.


I have the feeling the compressor is actually cycling on and off.
Like it would prevent from freezing. The temp at the vents drops
below 40F and then goes up over 40F and the cycle repeats.
Do you think something is wrong with the system ?

If I look at the working system compressor wheel and see the
clutch engaginh and disengaging cyclicly - that would be bad?
I need to do such experiment.

> Most of the time I charge a few ozs, never charged more than 6oz or 1/2
> a can for a long time. There will always be some left because the low
> side never gets below say 25-30PSI. It would start fast and then slow
> down quickly. It helps to wrap a warm towel around it. It will also
> help if someone revs the engine at 1500 rpm. That should be where you
> check the pressures anyway (do check the rev specs for 95!).


How long (in minutes) does it take to suck a half bottle of freon 6oz for you?
Anyway - I can rev the engine up from under the hood just by pulling
the trottle cable. It is located on top, above the valve cover/air intake.
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Old 16 Aug 2006, 01:24 pm   #6 (permalink)
mrdarrett@gmail.com
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Default Re: 1995 R134a air-condition malfunction


Pszemol wrote:
> <johngdole@hotmail.com> wrote in message news:1155701805.469106.246450@m79g2000cwm.googlegr oups.com...
> > You don't want to put too much freon into the system. I had my at
> > 35/230, at the upper range, during 90F outside air temp.

>
> So I have still room to put more.
> BTW-I still see the bubbles in the sight glass.
>
> > Sometimes extremely low low-side pressure is because the expansion
> > valve is stuck and the compressor will cycle on and off all the time.
> > But from the looks of 205 that's not the case.

>
> I have the feeling the compressor is actually cycling on and off.
> Like it would prevent from freezing. The temp at the vents drops
> below 40F and then goes up over 40F and the cycle repeats.
> Do you think something is wrong with the system ?
>
> If I look at the working system compressor wheel and see the
> clutch engaginh and disengaging cyclicly - that would be bad?
> I need to do such experiment.
>
> > Most of the time I charge a few ozs, never charged more than 6oz or 1/2
> > a can for a long time. There will always be some left because the low
> > side never gets below say 25-30PSI. It would start fast and then slow
> > down quickly. It helps to wrap a warm towel around it. It will also
> > help if someone revs the engine at 1500 rpm. That should be where you
> > check the pressures anyway (do check the rev specs for 95!).

>
> How long (in minutes) does it take to suck a half bottle of freon 6oz for you?
> Anyway - I can rev the engine up from under the hood just by pulling
> the trottle cable. It is located on top, above the valve cover/air intake.



Have a look here:

http://www.turboninjas.com/camry/ac.pdf

See also around page 25/26 or so - "Insufficient Refrigerant", "Poor
Circulation of Refrigerant".

Have fun, take safety precautions...

Michael

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Old 17 Aug 2006, 12:02 am   #7 (permalink)
johngdole@hotmail.com
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Default Re: 1995 R134a air-condition malfunction

> If I look at the working system compressor wheel and see the
> clutch engaginh and disengaging cyclicly - that would be bad?


Your system sounds normal, actually. The modern system's compressor
should cycle on and off and let the liquid freon work through the
expansion valve. According to Haynes manual, you are getting it down to
40F (or generally 30-40F below ambient in hot weather) you should be
OK.

But it's a good idea to check the evaporator drain valve to make sure
it's not plugged by spiders, etc. So the moisture can drain out.

When the system in not operation, the equalized pressure (measured at
Low side) should be around 60-90 psi. Measure this overnight.
Overcharging is not good, probably worse than undercharge. Other than
this, the home mechanic can do very little. When it doubt, it's better
to take it to an AC specialist.


> How long (in minutes) does it take to suck a half bottle of freon 6oz for you?
> Anyway - I can rev the engine up from under the hood just by pulling
> the trottle cable. It is located on top, above the valve cover/air intake.


I never clocked it, but I don't think it took more than 10-15 minutes.
A few repeats of warming it up, reconnecting, and charging until it
reached 35 PSI.

Check out the AC system FAQ and How-to Videos at Interdynamics:

http://www.id-usa.com/how_to_videos.asp

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Old 17 Aug 2006, 04:05 pm   #8 (permalink)
Pszemol
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Default Re: 1995 R134a air-condition malfunction

<johngdole@hotmail.com> wrote in message news:1155790937.598853.291190@75g2000cwc.googlegro ups.com...
>> If I look at the working system compressor wheel and see the
>> clutch engaginh and disengaging cyclicly - that would be bad?

>
> Your system sounds normal, actually. The modern system's compressor
> should cycle on and off and let the liquid freon work through the
> expansion valve. According to Haynes manual, you are getting it down to
> 40F (or generally 30-40F below ambient in hot weather) you should be
> OK.


But still it does shut itself off from time to time and the lamp
on the A/C button blinks then. When I turn the button off and
then on after a minute or two, a/c works as normal, untill
it shuts off itself again...

> But it's a good idea to check the evaporator drain valve to make sure
> it's not plugged by spiders, etc. So the moisture can drain out.


Moisture drains very well... I have wet puddle under the car
after parking.

> I never clocked it, but I don't think it took more than 10-15 minutes.
> A few repeats of warming it up, reconnecting, and charging until it
> reached 35 PSI.


I could place the can on the exhaust sheild :-)
The hose from the can is long enough :-))))
That would keep it warm ;-)

> Check out the AC system FAQ and How-to Videos at Interdynamics:
>
> http://www.id-usa.com/how_to_videos.asp


Thanks everybody. I downloaded the A/C repair manual too...
Need to study it a little and maybe I will find out how to diagnose
it shutting off on its own.
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Old 18 Aug 2006, 12:51 am   #9 (permalink)
johngdole@hotmail.com
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Default Re: 1995 R134a air-condition malfunction

Well, you've already charged pretty much a can. If it still is giving
you problem, it's time to take it in to an AC specialist or the dealer
to read off the diagnostics code in the AC controller. Don't charge any
more freon. I don't think the previous mechanic who over tightened the
belt should be whom you visit.

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Old 18 Aug 2006, 03:22 pm   #10 (permalink)
Pszemol
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Default Re: 1995 R134a air-condition malfunction

<johngdole@hotmail.com> wrote in message news:1155880285.428637.272900@h48g2000cwc.googlegr oups.com...
> Well, you've already charged pretty much a can. If it still is giving
> you problem, it's time to take it in to an AC specialist or the dealer
> to read off the diagnostics code in the AC controller. Don't charge any
> more freon. I don't think the previous mechanic who over tightened the
> belt should be whom you visit.


The previous mechanic was a toyota dealership :-)

I went to the same place and ask them how would they deal
with an intermittent problem like this. If there are some error
codes stored in the computer they can read...
I got the response that the A/C system is not recorded
in the ECU so there are not codes stored there to read.
I would have to bring the car in when it happens in order
for them to look at it.

The problem is that it does not happen often, so the chances
are that I bring the car for the diagnosis just to find out that at
this particular moment everythis was perfectly fine with it :-)
He said it could be the compressor clutch, pressure switch
or the A/C control unit itself - and they will not be able to
tell what is wrong until the problem would present itself.

Not sure what to do after hearing this story at the Toyota.

I am tempted to hook up some indicator lamp to several
sensors and observer their operation during driving :-)))
Any ideas what to look at and how to hook up some indicator light?
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