A/c performance question

[schierholz]

The story is.
I went to a shop and had them convert my system to 134a. they found a leaking hose which I replaced the gaskets and hose. they then next filled it with oil and freon (134a) and it worked for about 4 or 5 days. then it quit so I went back and they gave me the run around that they didn't have the dye so on so forth.

I decided to go to autozone and get the hose for filling the system and I ended up putting two cans of the strait freon without stop leak or the one with UV dye

It works great I put it in on last Friday (5/1/15) it's held I found the converted connector lose so I tightened it.

The question is when the compressor is running according to my gauge it drops to about 28/30 PSI then when it kicks off it pressurizes up to 40 psi mark then the compressor kicks back on and it falls to about 28 or 30 psi mark. Is this a decently well working system or should I expect something?
The vents record about 45 degrees at the coldest.

[Losiracer2]

my 92 LX's compressor gets the center vent temps to about 36 degrees with my R134a retrofit. So there is room to improve.

You really need to go to Autozone and rent their gauge manifold set and see what your high side pressures are reading. You should be around 250psi at high RPMs otherwise you compressor's high pressure relief could be limiting it from turning on.

I think i might have a problem with my expansion valve, as it could be clogged. I'm getting ice cold frigid 35-40 degree temperatures most times, but sometimes it'll hover around 55-65 degrees even with the compressor clutch on.

I even put a vacuum to the entire system for an hour before charging it up. I've never done an expansion valve before so lets hope that's not the problem