Does the receiver dryer have a cold spot on it?

340 psi is way too high for a discharge temp of 145f.

The low side is good, the TXV is doing it's job. The compressor is in good shape if t will push 340 psi The 340 psi is a condensing problem. Either external airflow or internal refrigerant flow. It has a Parallel flow condenser, so either is possible. First thing to check is the fan operation. Worn ...

I don't doubt that dry lock is an issue, especially farther north. It would seem that an accumulator added to the suction line would be in order - certainly what we would do in stationary. When I convert CCOT systems to TXV I leave the accumulator in place. Does not seem to create any issues. I add ...

MACS is not the EPA. Adding refrigerant to a system you KNOW has a huge leak is KNOWINGLY and WILLFULLY releasing refrigerant.

Right now, the only parts working properly in your system are the compressor and the cycling switch. The refrigeration system works because of a restriction, in this case the Orifice Tube. Any additional (and unwanted!) restrictions can usually found with a physical inspection - they usually get col...

You transfer the switch from your old compressor to the new one.

Poking around at an evaporator is not the best plan.

Go here:
http://eautorepair.net/Marketing/Default.asp

Spend the 20 bucks for a one month subscription to the complete Factory Service Manual. Find out exactly how and where the sensing bulb gets installed.

The sensing bulb must make firm, mechanical contact with the actual evaporator. If it is just swinging in the breeze near it, the evaporator can reach freezing without the bulb sensing it.

What exactly did you charge it with? What were the High side & Low side pressures after you serviced the system?

No. Use some non drying body sealer to seal up the gap around the case where the evaporator line exits. Check the evaporator inlet line as well, it is probably leaking air too. Check the evaporator case seam as well for leaks. Leaks like these can bring unwanted engine compartment fumes inside the c...