[amin.zallaghi]

Hi all
I live in a location where the temperature reaches 50°C in summer. In this season, when the car is stationary and does not move, the air conditioner compressor is turned off but The blower is active. The air conditioning system has no problem when moving and does its job properly. What is the problem? Is this a factory setting to prevent excessive pressure on the engine?

 

[200_S_AWD]

Is the electric radiator/condenser fan moving air at stops? The fan really isn't needed if the car is moving at highway speeds.

There is a high-side pressure transducer to tell the PCM to engage or disengage the A/C compressor and condenser cooling fan. The compressor and fan should both be turning at idle.
The high-side & low-side refrigerant pressures need to be within specification. Over-charged or under-charged can prevent optimum cooling.

The Alfa-OBD should be able to read what the PCM sees for A/C high-side pressure and interior evaporator temperature.
You want to see the evaporator as cold as possible without the danger of ice (about 2℃). Use the Alfa-OBD for diagnosis.

An old trick to boost cooling is to spray the condenser fins with water or diluted alcohol (windshield washer fluid). This evaporation will cool down the condenser more which will cool down the interior more.
A small electric pump can spray a mist onto the fins behind the grille.

We have done this on turbocharged engines with intercoolers. If the intercooler is made colder, the intake air is denser (turbochargers compress air and increase the heat, this makes the air less dense). A denser air charge contains more air (oxygen).

 

[amin.zallaghi]

No, all fans work. But the compressor is disconnected and connected. When I start moving, the compressor problem is solved, I feel that moving helps to reduce the temperature around the compressor. Of course, the engine temperature is normal and does not exceed the allowable range. What number should the refrigerant pressure be on?

 

[200_S_AWD]

This may be a 'cycling' compressor that only runs when needed.
Pressures depend on ambient temperatures. See attached.

 

[amin.zallaghi]

I cheked all piping, wiring, and etc about a/c
All of them is normal
A/c work normally when i drive but when the car is stop, ac compressor go off and on. RPM up and down too.

 

[200_S_AWD]

The PCM engine computer will open the throttle body slightly slightly when the A/C compressor engages, to raise the speed for the anticipated added load of turning the compressor.
The idle speed might vary a small amount. The idle speed change shouldn't be too drastic. A couple of things can cause this.

1. A low charge may make the engine 'overshoot' the idle increase because the added load is less than expected. Frequent compressor cycling can also be a symptom of a low refrigerant charge.
2. The PCM software was updated in 2018 (Technical Service Bulletin #18-083-18) to address some false fault code sets, idle quality issues, catalyst protections & a slight improvement in acceleration. DTC=Diagnostic Trouble Codes.
You may or may not have the code sets and still have the problems.

 

[amin.zallaghi]

And another reason to have alfaobd😃

Edit:
I raised the issue with the repairman. He guessed the problem was from ac compressor vavle. But he could not find a way to try it