Working on an MP66 cold plate system that the previous company walked away from. System was R12, last company put in 409. Wouldn't pull below 0 cold plate temp, cold plates freeze at -10. I put in MP66. Had high compressor outlet temps and had to run compressor superheat very low to get below -10. Just put in a liq/suc heat exchanger trying to raise comp superheat.........well it did. Up to 80 to 100 degress. Tried various evaporator superheats, no luck, still see very high comp outlet temps. Been trying various settings until outlet temp gets to 225, then shut it down to cool. Looks like I made things worse, as usual. What am I missing? Only thing I can think of it that I need an equalized TEV. Don't know what the pressure drop is across the plates but there's a fair amount of tubing in them (probably 60 ft. of 3/8). Help!!!!!

Thanks, Kevin