Walk in freezer wont cool below 5 degrees

[deven64t]

I changed out the skid on the freezer due to the last comp would not pump down below 10 psi also noticed brown oil when I removed my hoses, So I changed the skid, TXV , used flush and nitrogen to blow out the evap and lines, lots of nasty oil came out. I also removed the feeder tubes and blew out each set of tubes in the evap, NOW, started the unit up,,it had a low DT , around 8 deg ,, and frost started to form instantly across the evap and onto the suction line,,, as the box approched 5 deg my DT drop to 2 deg. I know this isnt enough info,,Ill get more when I go back,,But I adjusted my TXV to reach Factory specs ,,< 404a > im running a - 20 saturation {Evap } but my sub cooling wont change ,,,it stays in an area of -1 to 3 deg,,the factory said to run a 5 deg subcooling,, sight glass is full,,I know this because I tried to raise my sub and It started to Bubble,,I even tried to over charge the unit,,,but stop at 400psi , Do you think the Inside of the evap is coated with oil??
I will return ASAP with this info

Evap air in temp
Evap air out temp
Low side pressure
Suction line temp at TXV bulb

Cond air in temp
Cond air out temp
High side pressure
Liquid line temp at receiver outlet

[Ray123]

Did you check the copper piping? Maybe it is bent somewhere along the liquid or suction line.

[Brian_UK]

Now that you have adjusted the TXV fault finding is going to be that much harder.

[Magoo]

Did you gas charge or liquid charge the R404A.
magoo