Air Conditioner Mystery

1992 525i 120,000 miles

My Ac will not work and it really has me stumped.
I would appreciate any help.

Everything works, but it will not get cold.
New compressor
new expansion valve
new dryer.

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I blew out all the tubes with air compressor when I had it apart.
put it back together pulled a vacume (no leaks)
added half a can of r134 , compressor kicks on, and low side shot up to 90 psi,...
high side 0.
shut compressor off and they equlize. this is odd?????
I don't understand why it only takes a half a can or 134 and the pressure shoots up so high??

If I run the compressor for a while at 40 psi on the low side, nothing gets cold.
I checked all the tubes nothing cold.
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The ac button engages, ( blue dot on dial turned down) ,the condenser fan comes on, inside temp gage works, compressor kicks on, blower fan on.



If anybody has any ideas I could really use some help. thanks

Mystery Solved!
When I coverted the system to r134 i put the high side nipple on the low side, so I have been trying to charge the high side.
Swapped them out and it took a charge right away.