R12 -r134a problem

[1991mj]

 I was trying to convert my 91 comanche to r-134a today I replaced all the o rings, dryer, expansion valve and got all the old oil out of it and had it on a vacuum for awhile, then I filled it with r 134a and it took a long time to fill and while it was charging it would blow at like 60 degrees out of the vents for like a minute then stop and blow like 80 degrees for alittle. Then  when i disconnected the machine it would only blow warm. The compressor kicks on and so does the cooling fan, the system called for 2.38lbs and I put 1.90 lbs should I have put more in? Also since it took so long to fill did I have the service valves on the lines coming out of the compressor in the wrong position? I saw some picture that said they should be at the "mid position" for filling and such but I'm not entirely sure how many turns it takes to get to that position.... any help would be appreciated sorry for the long post

[eaglescout526]

Yes you need to put more in. 2.3lbs will do it(the tech I had fill mine did it to 2.4, no adverse effects). What probably needed to be done as you filled it was run the engine and turn on the AC to cycle some refrigerant through as your putting more in.