clogged filters,dirty coils condensers,evaporators
2 reasons for the system to cut out, low pressure, and high pressure. I am thinking you are experiencing low pressure and need to recharge your system.
The low pressure connection for your 1993 Jeep Cherokee air conditioning system is located on the top of the air conditioning compressor. There is a low pressure connection and a high pressure connection, both should be labeled.
dirty coil
You are on the wrong port. Some fords have an extra port that the low side hose screws on but is a high side fitting. look for another port.
check condenser
Refrigerant leaving a compressor in a car's air conditioning system is a high pressure, high temperature vapor. This vapor carries heat energy away from the evaporator coil inside the car, allowing the refrigerant to absorb heat from the cabin air and cool it down before circulating it back.
There are two schrader / port valves to the air conditioning system. One will be a high pressure and the other will be a low pressure. You need a certified mechanic to check and refill the system. You can not simply refill the system.
It is called high pressure for a good reason. The high pressure side can and will pump the refrigerant back into the can of refrigerant and explode in your hands. One more reason to let the professionals work on the air conditioning in your vehicle.
There are several causes for high fuel consumption in a diesel engine. These include a difference in the weight of the vehicle, increased usage of air conditioning, and a difference in tire pressure.
The expansion valve separates the high pressure and low pressure sides of the air conditioning system and acts as a metering valve to control the flow of refrigerant. It reduces the pressure and temperature of the refrigerant before it enters the evaporator coil to create cool air for the interior of the vehicle.
http://www.unicosystem.com/ This is a high velocity system, hopefully what you are looking for.
discharge pressure is high, suction pressure is high superheat is low and subcooling is high.