By those gauge numbers the system is low on refrigerant and compressor may well be cutting off. (low psi cutoff)
Charging should be done on nice hot days:
1. With the engine at 2000RPM or slightly higher if the neighbors don't complain
2. Engine at operating temperature
3. Decklid CLOSED and towels blocking air leaks where the manifold hoses come out.
4. A big fan blowing air down into the grill...unless you got condenser mounted fans
5. AC on HIGH cold and HIGH fan!
6. Refrigerant gets added through the low side little by little...several minutes..
High pressure cutoff to the compressor (if your pressure switch is not faulty) is around 400PSI So the compressor will not cut off for high pressure unless you have no air through the condenser. Way too much refrigerant or something is plugged.
Low pressure charge for R134a is ambient temp based but say 90F then the low side needs to be close to 45-50PSI.
The low pressure cutoff switch is around 20-30psi!. Your compressor will shut off because of low refrigerant. Your pic shows 10psi..The compressor should not run.
If you have condenser fans then they should come on at around 240-260PSI and switch off at about 180PSI but this is based on the trinary switch design.
You can watch them work by dropping your RPM to idle and letting air in under you decklid. Pressures will jump and the fans will come on if set up correct. But at idle the fans may not be adequate to keep your high side from rising to compressor cut out.
