A/C Low pressure reading high!!!

[jnuncio3]

I have a 2006 CRD 2.8L. I noticed that my A/C was not cooling very well. I placed a thermometer in the center left outlet and my temp was 75F. Ambient temp was 90F. I figured that I just needed to add some 134a so I hooked up my quick recharge hose with gauge. It almost went into the RED zone. Yes I was connected to the Low Pressure Port. I connected my low pressure gauge and the pressure was cycling from 90psi to 115psi. Cycle time is approx 10 seconds at 1200RPM. this system has not been serviced for three years.
Question, What would cause my Low Pressure to be this high and still allow the compressor to cycle. I did not add any 134a so I dont understand why my Low pressure is this high while cycling.

 

[JeepJeepster]

Whats the high side pressure?

 

[jnuncio3]

Apparently my CRD was not going into MAX cooling and was still pulling in ambient hot air. I cycled the mode selector from stop to stop several times and placed a high flow fan in front of the grill to reduce the heat loading. Temp coming from the center outlet dropped to 46F and Low pressure dropped to 42psi. All seems to be working fine now. Maybe just some crud in the mode selector.