i just purchased a 92 civic lx with a history of a/c leaks. the past owner had the compressor replaced about 3yrs ago by honda and it worked for the season but then it stopped. they drove the car for 2yrs without a/c. I inspected the system and replaced the o-rings on the high and low sides found a couple loose connectors and cleaned out debris that blocked about 1/3 of the evaparator coil. I purged the lines and filled the system with an R-12 susbitute called "enviro-save" based on there r-12 conversion chart which was about 23oz. it works on on warm days but on hot days dosen't cool very well. The compressor does not cycle and the low/high pressures are steady at 50/175 when the ambent temp is 92. The vent temp is about 70 even after running 10-15 minutes with fan on max/recycle and both front doors open.
I read on the web the low side should be about 25-35 and the high side should be between 200-230 when the ambent temp is 92. I am not sure if this is true but i would think the vent temp should be about 30 degrees below the ambent temp. I would be most thankful for any assistance.