Honda Car Forum

I just added refrigerant to my 1995 Prelude SE (125,000 miles), and noticed
both while I was recharging and after that the compressor doesn't cycle off.
Is it normal for Honda compressors to run full-time (while the "A/C" button
is on)? I can't specifically remember if it cycled during the years I've
owned it. If it SHOULD be cycling, what would prevent it from doing so?
Using the manual "A/C" button on the console does cause the compressor to
turn off, as normal. One item to note, is that I used one of those
inexpensive "system recharge" packages from the auto parts store to add
refrigerant, which seemed to work well, but it only measures low-side
pressure. Thanks for your help.

It is normal for the A/C to cycle on and off unless the temperature is
quite high. In warm weather it typically have a higher duty cycle in
"Fresh" than "Recirk". (Opposite if using the A/C in cool weather e.g.
to defog).

The cycling is controlled by the thermostat mounted in the evaporator
housing. Specifically, the ECM controls the A/C compressor clutch relay
based on a call for cooling. The call for cooling gets to the ECM
through (in order from ECM to ground) 1.) the A/C pressure switch in one
of the refrigerant lines, 2.) The A/C thermostat in the evaporator
housing, 3.) the A/C main on/off switch on the dash and 4.) the
ventilation fan switch on the dash (separate pin grounded with fan
switch in any position except off). The A/C pressure switch is a
safety-lockout. This switch is normally on at all times.

>From my home central A/C I know that too much refrigerant will reduce
the cooling capacity of the A/C system. Perhaps you overcharged the
system, have reduced cooling capacity and thus the evaporator never gets
cold enough to turn off the compressor? Measuring only the low-pressure
side is somewhat dubious. For proper charge, filling to a specific
pressure is not sufficient, the correct pressures (high and low side)
depend heavily on outside temperature *and* humidity. Since R134a is
cheap I would try removing some refrigerant (observing all relevant
environmental regulations, precautions and safeguards) and see if that
helps.


Andrew McCune wrote:
>
> I just added refrigerant to my 1995 Prelude SE (125,000 miles), and noticed
> both while I was recharging and after that the compressor doesn't cycle off.
> Is it normal for Honda compressors to run full-time (while the "A/C" button
> is on)? I can't specifically remember if it cycled during the years I've
> owned it. If it SHOULD be cycling, what would prevent it from doing so?
> Using the manual "A/C" button on the console does cause the compressor to
> turn off, as normal. One item to note, is that I used one of those
> inexpensive "system recharge" packages from the auto parts store to add
> refrigerant, which seemed to work well, but it only measures low-side
> pressure. Thanks for your help.

Randolph wrote:
> depend heavily on outside temperature *and* humidity. Since R134a is
> cheap I would try removing some refrigerant (observing all relevant
> environmental regulations, precautions and safeguards) and see if that
> helps.

hehehe... you really think hes going to run out and buy a rig to get
that 134 out? or just take a small screwdriver and release it through
the schrader valve?

SoCalMike wrote:
>
> Randolph wrote:
> > depend heavily on outside temperature *and* humidity. Since R134a is
> > cheap I would try removing some refrigerant (observing all relevant
> > environmental regulations, precautions and safeguards) and see if that
> > helps.
>
> hehehe... you really think hes going to run out and buy a rig to get
> that 134 out? or just take a small screwdriver and release it through
> the schrader valve?

Let's just say I know which way I would do it...

Randolph wrote:

> SoCalMike wrote:
>
>>Randolph wrote:
>>
>>>depend heavily on outside temperature *and* humidity. Since R134a is
>>>cheap I would try removing some refrigerant (observing all relevant
>>>environmental regulations, precautions and safeguards) and see if that
>>>helps.
>>
>>hehehe... you really think hes going to run out and buy a rig to get
>>that 134 out? or just take a small screwdriver and release it through
>>the schrader valve?
>
>
> Let's just say I know which way I would do it...


LOL... well, at least its not "real" freon. id definately recommend
gloves, too and a long, thin screwdriver...

Thanks for the responses. I paid attention on the way home from work today,
and it is now indeed cycling (and cooling rather well). Obviously I'll know
soon enough if there is a leak and if so, if it persists. I've had my share
of contact with a/c refrigerant and I'm not afraid ;-] One thing I
neglected to mention in the original post: During the "decline" of a/c
performance, I noticed a sound coming from what seems like under the dash
(in the evaporator area) that can best be compared to the sound the
cappuccino machine makes when frothing the creme; a hissing/spitting sound.
Since the onset of the cooling problem, I've noticed this sound probably 85%
of the time, after I turn off the engine (it could be making this sound as I
drive, but the engine noise drowns it out). At any rate, I'm happy enough
at this point with the system to not be THAT worried about it.
"SoCalMike" <mikein562athotmail@hotmail.com> wrote in message
news:ZAm1d.86259$3l3.58876@attbi_s03...
> Randolph wrote:
>
> > SoCalMike wrote:
> >
> >>Randolph wrote:
> >>
> >>>depend heavily on outside temperature *and* humidity. Since R134a is
> >>>cheap I would try removing some refrigerant (observing all relevant
> >>>environmental regulations, precautions and safeguards) and see if that
> >>>helps.
> >>
> >>hehehe... you really think hes going to run out and buy a rig to get
> >>that 134 out? or just take a small screwdriver and release it through
> >>the schrader valve?
> >
> >
> > Let's just say I know which way I would do it...
>
>
> LOL... well, at least its not "real" freon. id definately recommend
> gloves, too and a long, thin screwdriver...