Help: baffling 86 Astro a/c problem

to the experts:
A few months ago I switched my wife's Astro 4.3L van to 134. New parts: (rebuilt) compressor (reman), accumulator, orifice tube/filter, and new "O"
rings throughout. I pulled a 28psi vacuum, added 8.5oz oil, and 2 1/2 12oz cans of 134a. The compressor keep cycling until I got to the last can when it stayed on all the time (fan on high, lever on max). Air temp at the vents was approx. 55 F.
The system ran great until last week when she told me that it wasn't working anymore.
The air is blowing warm. It was low on 134a, around 20 psi suction, but not empty. The discharge line was hot, and the suction line is warm. There was a very slow leak at the pressure switch. I replaced it.
Not knowing if anything else was wrong, I decided to flush the evap and condenser. They both blow air freely. I also emptied the accumulator. The oil looked blackish.
Now here is the baffling part: I drew a vacuum and add 8.5 oz can of oil. I add the first can of 134a and the compressor is now engaged without cycling. Suction pressure is already 30psi, discharge about 180. I add part of the second can and suction went to 50 and discharge 230. I stopped adding. The discharge line is now hot and the suction line to the accum is warm. The compressor is starting to make noise, I guess due to the high pressure. Air at the vents is still warm.
What could be causing this?
TIA
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YOu still might have too much oil in the system since you did not drain the compressor. 8.5 oz seems a little much to me. Are you sure that is the correct amount?
Tim

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What type of oil ? If you used PAG oil, you could be in for trouble. If it's ester based, 8.5 sounds like a lot. *Never* use compressed air to test a R134A system, this oxygenates the refridgerant, and can cause it to become unstable. Evacuate first, that use air, than re-evacuate before adding R134A.
Recover freon, open system, and check orifice tube for clogging.
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I believe it was Model #EEO-6 ester oil from http://www.id-usa.com/oils.htm But I threw the can away and can't be 100% sure. So I will open the system up and flush again (ugh).
I used compressed air to "pop" dry the components while they were off the car. http://www.delanet.com/~pparish/flushing.htm I drew the vacuum after the system was reassembled.
I should have mentioned this before: when I removed the orifice tube, I noticed that I had previously installed it upside down. However, it worked for 4 months like that. It was stuck way down inside the evap inlet pipe, and the bottom was bent in the shape of the curve in the evap pipe. The inside of the evap inlet pipe looks boogered up. I picked up an A/C orifice tube repair kit yesterday and will install it this afternoon.
Is it possible that the evap or the condenser can be partially blocked?
TIA Bill DFW - today 105 F predicted

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