In HVAC hell! Advice appreciated

[Spicyfly]

Hello all!

I'm in a 2001 Ford F-250 with the 5.4. It was ordered from the factory with no a/c and it was fine by me, but my new wife talked me into putting air con into it.

I've done this before without issue but this puppy is just giving me issue after issue.

As a bit of a preface, l'm an auto technician (but do not specialize in HVAC at all) and therefore, have all the necessary equipment to do the job properly just not a full grasp on the theory for diagnostics (this is forcing me to learn though!)

All components are new and OE style for my truck, installed high and low pressure switches with a “module” to control them, and build a controller that reads evap temp to cut the compressor to prevent freezing. Fabricated baffling to go around condenser and installed two aftermarket condenser fans (along with the stock belt driven clutch fan). And rigged a recirculate door.
I charged the system to the mfg specified weight of 2lbs 10oz on the sticker but head pressure instantly went to 400+ so l cut it off and decided to try a pressure/temp charge. Started with 1.5lb and added until pressures were 275/40 (l'm in SW Florida so it was about 90-95 degrees at more or less sea level.)

I measured evaporator inlet and outlet temps, I don't remember what they are and don't have my notes but I do remember there was about a 40-50 degree difference between the two; the inlet being very cold outlet not much colder than ambient and that doesn’t seem right to me.
This is frustrating to no end! When I have the time I want to check flow through evap or possibly change out the orifice tube but I don't know?
Thanks for any advice!

TL;DR I am trying to put ac in a non ac truck and getting my hind end handed to me.

Again, I have all the tools and materials to be EPA compliant.

(This has been asked of me before, so for anyone curious: the reason I didn’t just dump this truck and buy a similar that came with A/C is that I’ve simply put too much work into making this truck reliable/mine. Fully overhauled the engine, rear axle and driveshaft, replaced entire clutch system - including master and slave cylinders, front suspension and steering. I’ve just put too much blood, sweat and tears into this thing to just get rid of it! Plus, as with everything I’ve done to this Pig, I really wanted the project as a learning experience.)

[tbirdtbird]

Pipe in and pipe out of evap s/b about the same, look for issue with expansion device