New to the forum and this problem is one I think I know the answer to, but want some additional input before I try it.
I bought a used 2000 Honda Accord A/C was not working. Checked pressures, and the thing was empty. Drew a vacuum on it and it holds. So I started to put 12 oz of 134a into it. It took a long time (15 minutes) but I did hear/see compressor kick in and out. Maybe 4 seconds on, 10 seconds off. With the gauges, I saw the high and low side pressures always equal. When the compressor was off, both would go down to around 40. When the compressor kicked on, both went up to 110. This was after the 12 oz of 134a was in.
So my guess is the expansion valve. anyone think I am right?

 

You may have a clogged filter drier or your compressor valves are done and not fully sealing. Try replacing the filter drier and see what happens. If not you may have to change the compressor. You should go to a certified technician to check it out.

 

I would say expansion valve too, obviously you'd replace the drier too. I'm curious if it's actually getting cold ? Check the inlet hose to the evaporator at the firewall. They usually fail closed but perhaps yours is failed open.

 

One tube really cold (maybe 45-50) then other tube warmer, it was a cool day when I did this, probably 60 outside