Need help charging A/C

UglyDuck

TJ Enthusiast
Supporting Member
Joined
Dec 10, 2021
Messages
404
Location
Goodyear AZ
Charged the AC but not getting cold enough temps according to the book specs. Done everything right I think, pretty well versed on the process. Throwing my hands in the air now.
 
What are your pressures with the system running?

938C5CBA-BFC5-4CE4-8773-29BD9DE521FD.jpeg
 
Just to start at the basics - You evacuated the system, pulled a good vacuum, and measured by weight how much refrigerant was added?
 
Unless you're doing that in an air-conditioned garage, that high side looks pretty low to me. Even ignoring the FSM which seems to have very high targets for high pressure, standard R134a pressure charts want to see in in the range of 225-250 (if it was only 85 out when you did this) to 275-300 (if it was 95 out), and over 300psi if it was over 100 degrees.
 
Unless you're doing that in an air-conditioned garage, that high side looks pretty low to me. Even ignoring the FSM which seems to have very high targets for high pressure, standard R134a pressure charts want to see in in the range of 225-250 (if it was only 85 out when you did this) to 275-300 (if it was 95 out), and over 300psi if it was over 100 degrees.

I agree. High side looks low according to book numbers. Yes it’s an air conditioned garage but ambient temp about 80-85 at that time.
 
I agree. High side looks low according to book numbers. Yes it’s an air conditioned garage but ambient temp about 80-85 at that time.

Are you charging by weight because I went that route initially and wound up adding an additional 5 or 6 oz's to get my pressures correct.
 
Thing is, I’m there with the low side but not the high. So I’m confused and even more so, frustrated as this is the second attempt.
 
I don't like the TJ FSM's pressure chart because apparently whoever wrote that chart thinks Jeeps can violate the laws of physics - R134a is R134a and the high-side pressures the FSM wants to see are way above any other reference I've ever seen. I suppose they're covering a 10 degree step instead of five, but it still trends high. Every other FSM I've seen is in line with this chart:

R1dEUJW.png


With that said if you're at 85 degrees ambient then I'd follow the flowchart on the next page of the FSM starting with "normal pressures but temperatures too high". Oil overfill seems unlikely unless you've used one of those combination cans with oil and R134a in it, so I'd double check the blend door control and possibly the door itself to make sure it's not mixing heated air.

After you verify that then I'd plan on getting the system evacuated, and open it up to see what's in there.
 
I don't like the TJ FSM's pressure chart because apparently whoever wrote that chart thinks Jeeps can violate the laws of physics - R134a is R134a and the high-side pressures the FSM wants to see are way above any other reference I've ever seen. I suppose they're covering a 10 degree step instead of five, but it still trends high. Every other FSM I've seen is in line with this chart:

View attachment 338127

With that said if you're at 85 degrees ambient then I'd follow the flowchart on the next page of the FSM starting with "normal pressures but temperatures too high". Oil overfill seems unlikely unless you've used one of those combination cans with oil and R134a in it, so I'd double check the blend door control and possibly the door itself to make sure it's not mixing heated air.

After you verify that then I'd plan on getting the system evacuated, and open it up to see what's in there.

Well I did use some oil in a can, but I had lost some oil after replacing the hoses. The problem is quantifying the loss or the add. I tried to limit how much went it but… hard to do/quantify.
I’m starting to question blend door as the low side hard line in the engine compartment is super cold.
Where in AZ are you? I might PM you if that’s ok
 
Unknown..... Would need yo hook up the gauges and do some tests. Just wandering, did you replace the receiver/ dryer when replacing compressor?
 
Unknown..... Would need yo hook up the gauges and do some tests. Just wandering, did you replace the receiver/ dryer when replacing compressor?

Replaced compressor, condenser, accumulator all at same time, worked amazing for about 3 weeks until a hose went. Replaced the hoses, never worked right since.
 
If a hose blew you might of lost some oil and a lack of oil. Am kinda shooting in the dark here. Did you add any oil when you replace the hose?