1988 Chevy Suburban r12-r134a retrofit problems

[bohica2xo]

Detroit:

In my experience those evaporators do a fine job. Plenum works just fine on big GM vehicles.

Tim:
Not just a front only A/C in a Suburban on 134a... The suction will drop all the way to 21 psi!

Seriously, the normal suction on a system like at at idle can be as high as 60 psi depending on ambient temp.

This is probably a chicom evaporator with blockages in most of the passages. No way the refrigerant that went past a 58 to 80f evaporator remains at 30 psi unless the compressor suction is outrunning the blockage and reducing the pressure of the hot refrigerant.

[LUTHER4130]

This Suburban came with just a single evap. It worked good when it was R-12.
From the sounds of it I have 2 choices.
1. Work on getting the charge just right.
2. Tear it apart again and replace the evap with one from a trusted manufacturer. Then work on getting the charge right.

I think at this point spending a little time on getting the charge right would be a lot cheaper and easier. If I cant get better temps right at the back of the evap then I will tear it apart again. What temp range should I be looking for 1/2"-1" from the back of the evap? ( Any suggestions on what the best evap brand is would be great).
Thanks again for all your input.
LUTHER4130