I have a 2005 RX-8 which has a weird AC issue.

Here are the readings
AC in max with recirculate on
Ambient temp is 86F
AC control unit temp setting is 0

Initial pressure readings when vent temp reaches its lowest value:
Vent temp is 52F
Low-pressure reading is 40psi
High-pressure reading is 200psi

8 minutes later

Vent temp is 56F
Low-pressure reading is 32psi
High-pressure reading is 175psi

The RX-8 pressure reading chart recommends at 86F ambient temp the following
Low pressure reading between 14 and 22psi
High pressure reading between approx 146 and 213psi

The symptoms: AC initially cools. AC clutch engages in 5 sec, stays on for 1 min 23 sec
After that clutch goes OFF for 5 sec, goes ON for 10 seconds, repeats.
AC will keep cooling as long as driving trip doesn’t have many stops or long stops.
If the car stops at a light for a while, AC will stop cooling and clutch will stop engaging.
If the AC is OFF for a while after that, then after it is turned ON, it will start cooling again.

Note that is AC setting is not at max, vent reading will get close to 40F

It seems that the low-pressure reading is too high.
Note that the standard pressure chart on the web recommends the following at 86F:
Low pressure reading 45-55 psi
High pressure reading 225-250 psi

It seems to me that my RX-8 wasn’t calibrated to the manufacturer's recommended value but some other standard setting.

Any recommendations?

 

Sounds like it might be low on freon; also, make sure the fan is running when the A/C is on.

 

I would bet that is is slightly overcharged. Likely someone thought that if a little was good....a bit more would be More better

 

Yes, that is what I thought. Thanks!