[Shotimes] Compressor doesn't cycle

[crusher@ipass.net]

Last time I checked on Car A/C units (and many smaller home units) they are
pretty simple. There are two pressure switches that continuously open and
closed based on pressure on the high and low sides of the AC system. If the
pressure in the high side is never reaching what that switch is looking for,
i.e. orrifice to large, or some other problem, you will GET cooling as the
compressor runs and circulates the 134a, but the compressor is liable to run
all the time because that higher pressure is never reached. 

As was stated in the other reply to this post, there SHOULD have been more to a
real kit. Then again, I drained and pulled vaccum on a 91 w/ a 3.8, filled it
with 134a, and the compressor does run longer, but it DOES cycle. 

I seem to remember the low pressure side being between 30 and 50 as the
compressor cycled and I don't remember what the high side was (I borrowed a set
of diagnostic / fill guages). 


Sorry I couldn't help more...


Carl



Quoting Kevin Galuska <whitegen1sho@hotmail.com>:

> After having the ac system on my '91 evacuated, I charged it with R-134a . 
> The kit I bought came with a gauge and when I was through with the process 
> it was read around 30 whatever the standard unit is. I ran the car for about
> 
> 10 min afterward and was getting very nice, very cold air out of the vents. 
> The only problem is that the compressor didn't seem to cycle, it just stayed
> 
> engaged the whole time. I have checked the clutch gap and it is in spec. I 
> know most people have a problem with the system cycling to often, and was 
> wondering if there is a problem with the system not cycling enough?
> 
> Kevin
> whitegen1sho@hotmail.com
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