Poor ac at idle..rpm 400 to 600

[earthrealm]

Have noticed for a while now that my ac performs sub normal at idle..or in drive with foot on brake in stop n go traffic.
Usually when i start the car..idle rpm is 1100 n then gradually reduces to 600 to 800 range after a few minutes..at this point..the ac is cold but not super cold as it usually is on the highway.
Fast forward a few days ago..after a 90mile highway trip..in which ac was superb..got into stop n go traffic...n ac performance dropped drastically..started to sweat. .rpm was at 500 range then...traffic later picked up n got to 70mph...n ac got super cold again.

Had a leak n bad compressor months ago...replaced compressor n condenser from rockauto...vaccuumed system n recharged to factory spec..ac worked ok.


My thinking is either the low rpm is causing the compressor to work sub optimally....or i may b a lil low on compressor oil...
Has anyone experienced this n how was it resolved

 

[BlackWorksInc]

RPM does sound a bit low, it could be a bit under or overcharged. When they installed the new compressor, do you know if the idle was relearned correctly? You may want to try cleaning off the throttle body, disconnecting the battery for a good 10~15minutes; then letting the vehicle idle with NO loads for about 5~10minutes and take the vehicle for a normal test drive and see if that helps the vehicle maintain a better RPM.

 

[earthrealm]

they didnt relearn the idle, but i have done that about 3 times after the procedure.
i have also cleaned the throttle body and the MAF sensor, prior to the ompressor swap.

there is no way to manually increase the idle right?.....
really stumped by this,

 

[earthrealm]

update: hooked up guages to the ac system, and found the pressures low, topped up with gas, and ac blows cold at idle, guess my mystery leak is still on, car has been extensively checked by a tech...no leaks found,. would have to try the dye in refrigrant method.

am thinking at low gas levels, the compressor can rerally generate enough pressure for the ac to chill at idle, but on the highway, with rpms in the 15000 range, the compressor is able to generate enough psi for the system to chill

 

[fayewong]

update: hooked up guages to the ac system, and found the pressures low, topped up with gas, and ac blows cold at idle, guess my mystery leak is still on, car has been extensively checked by a tech...no leaks found,. would have to try the dye in refrigrant method.

am thinking at low gas levels, the compressor can rerally generate enough pressure for the ac to chill at idle, but on the highway, with rpms in the 15000 range, the compressor is able to generate enough psi for the system to chill

Hi, reviving an old thread since I have the same issue but with a twist.

Since it is bloody hot here in the west and with temperatures over 110+ degrees. it seems my AC cannot get cold fast enough. Once i start driving, especially freeway, it would feel cold, but not ice cold ( not sure if it can be ice cold with the heat outside) .

The problem is, whenever I am at idle. the compressor will not work and it is blowing hot air until I start driving again. Whenever I am at a complete stop, it will start getting warm and then hot or outside temp air.

Here is the twist. Whenever my HVAC display shows the temp outside around 90 something degrees, it will start working normally and feel ice cold on LO to where I actually have to turn the temperature up. It will never feel like this when temps are 100+ , where I wish I can adjust the temperature lower the LO.

I already tried pumping in the refrigerant and the gauge was saying I had enough in there.

Anyone had this issue and found a way to fix it? Thanks. Got two more months of summer, so I am trying to see if I can get the issue fixed before winter comes.

 

[earthrealm]

hmmm, thats a strange one.
check if the temp sensor near the drivers kick panle is still connected, if disconnected, it would make the car chill only on low settings.

i also think your refrigrant may be over filled or underfilled, what are the low and hiside readings you have?