: Ac charging problems



miwise
08-07-10, 03:45 PM
Here goes. I tried to charge my ac myself. I think somethings wrong. I put the freon in and it wouldn't take it. The low side went to 70psi then stopped. When I revved it the low side went down in psi and high went up. Let off the gas and the reverse happened. Not sure what's going on. Could there be something in the ac lines or something? Maybe a bug crawled in? Confused. The compressor isn't drawing the freon in

mhamilton
08-07-10, 07:46 PM
Are you adding freon to a working system or an empty one? If the latter, did you pull a vacuum first?

zonie77
08-07-10, 08:42 PM
Here goes. I tried to charge my ac myself. I think somethings wrong. I put the freon in and it wouldn't take it. The low side went to 70psi then stopped. When I revved it the low side went down in psi and high went up. Let off the gas and the reverse happened. Not sure what's going on. Could there be something in the ac lines or something? Maybe a bug crawled in? Confused. The compressor isn't drawing the freon in


You have to go to an AC site and read up on what you are doing.

1) There is no way a bug gets into a sealed system.

2) That is actually what it is supposed to do. The 70 psi is the pressure of the freon can, it will drop as the can empties.

miwise
08-07-10, 09:14 PM
Yeah. I had the system disconnected for a little over a month. I understand the pressure of the can equalizing w the system. What I don't understand is why the system doesn't suck the freon from the low to high pressure side unless somethings clogging it. But then the question of why is the pressure changing when I revthe engine as I statedbefore? Baffled. I didn't realize there was an actual ac section. I thought I looked but must have overlooked it. Thx 4 the replies

Necrosan
08-07-10, 09:50 PM
It's not working because you likely have NO freon in your system; the compressor will not turn on until you reset ANY AC related codes.
Also, your 70 PSI reading means nothing, as the compressor was not running. You cannot get a proper low side reading with a can gauge without having the compressor engaged & spinning.

miwise
08-07-10, 10:12 PM
Compressor was running. All codes were cleared first. I could hear it running

miwise
08-07-10, 10:14 PM
Also. Was using a manifold. Ac manifold

Ranger
08-07-10, 10:16 PM
Did you pull the system to vacuum for a good 30 minutes or better first?

miwise
08-07-10, 10:44 PM
a vacuum pump anywhere. Shouldn't affect the charging though right? Still doesn't explain the reason for pressure flux

mhamilton
08-08-10, 09:18 AM
You must pull a vacuum on an empty system and hold it for 30 to 60 minutes. If you don't, then the system is full of air and there is no room for any freon. It won't work.

Once you pull a vacuum, that will pull in most of the 2 lbs of freon by itself. Then there is enough refrigerant for the compressor to start, and you can finish charging through the low side. The low side only has a "low" pressure when the compressor is running, and it will vary with engine speed and ambient air temperature.

Ranger
08-08-10, 11:59 AM
You must pull a vacuum on an empty system and hold it for 30 to 60 minutes. If you don't, then the system is full of air and there is no room for any freon. It won't work.
More importantly, there is moisture in that air that will freeze and block the system. Pulling a vacuum lowers the boiling point, boils the moisture and removes it.

miwise
08-08-10, 01:23 PM
That makes sense. I'll see what I can do about vacuuming it down. Is there a way to tell if the compressor is working. I would think it should make some type of boost right? Maybe not but I guess I'm just baffled. Or maybe the drier is full of trash and moisture? I guess I don't really understand. I don't want to waste money on charging up my system. Its 120 a pop. Every time I take it to the mechanic to do that. They charge 120 just to vacuum and charge the system. If the compressors bad I want to replace it before, but I also don't want to replace a perfectly good compressor. I'm thinking I should have just left the compressor in the car somehow when I removed the engine. This is a real hassle.

mhamilton
08-08-10, 01:57 PM
That makes sense. I'll see what I can do about vacuuming it down. Is there a way to tell if the compressor is working. I would think it should make some type of boost right? Maybe not but I guess I'm just baffled. Or maybe the drier is full of trash and moisture? I guess I don't really understand. I don't want to waste money on charging up my system. Its 120 a pop.

Is the compressor spinning? There's too many variables at this point to tell if the compressor has a problem or not. Was the air conditioner working before? A mechanic charged the system and didn't see if was functioning after charging?

If the system was left open for any length of time, the accumulator should be replaced at this point by default. If the integrity and cleanliness of the system are suspect you should stop and wait until you can replace all the necessary parts and flush the system. You have to do ac repair the right way or else it will just keep costing you more money and time and never function properly (if at all). If the system is full of debris you have to replace the condenser and flush out the rest of the lines, new oil, replace the failed compressor, etc. But that may not be the issue here... let us know what happened to the system.

miwise
08-08-10, 03:04 PM
Yeah. I disconnected the lines. I taped them up but the tape got removed by my nephew (the car was sitting up for over a month without an engine). I didn't see any evidence of anything getting into the system. I don't know though. I guess I'll start where you said and replace the accumulator / orifice / dryer, etc. It worked before removing everything. I'll certainly let you know. The compressor is spinning. I can hear it. It started getting loud the longer I tried to make it work. Louder and louder. I'm thinking I'll just flush out the a/c system at this point. Disconnect the lines and flush it all out. This engine problem has gotten very costly. LOL. SHould have scrapped the car and sold it to a junk yard.

Ranger
08-08-10, 05:10 PM
If the system is full of debris you have to replace the condenser and flush out the rest of the lines, new oil, replace the failed compressor,
And add the accumulator to that list. Like mhamilton said, there are no shortcuts in A/C repair. Do it right, or do it again.

If the system is not now charged, pull the orifice tube. That will tell the tale. If the compressor is failing and throwing debris through the system, it will get caught at the orifice tune screen.

miwise
08-08-10, 05:19 PM
Sounds like good advice. Is the orifice b/w the high and low pressure valves?

Ranger
08-08-10, 09:31 PM
I think the orifice tube on your car is at the coupler in the A/C line along the firewall on the passengers side, near the low side temperature sensor. Take note of which way it comes out. If you install it backwards, you'll damage that sensor.

zonie77
08-08-10, 09:43 PM
If the hoses were disconnected then yes, something could be clogging it.

When I said and AC site I meant a different website, I don't think there is an AC section here. AC sites will explain how AC works without us having to type a couple of pages.

It might be worth buying a vacuum pump (not the cheap ones that run off an air compressor, an electric one) to do it right.

Once it's left open the desiccant in the drier attracts moisture. When the system is operating that moisture can turn to ice and block the system. Also some impurities are acidic with moisture and will corrode the system internally, so evacuating it is very important.

You have to be sure the center hub of the AC pulley is actually turning the compressor.

miwise
08-09-10, 10:20 PM
Yeah. The center hub is turning. I can actually hear the compressor running. Maybe the accumulator is clogged up full of moisture. I'm assuming if the compressor turns then its good. I read several ac sites and kinda understand (especially after talking to you all) how the system works.

Here's what I found:
http://www.freeautomechanic.com/airconditioning.html . . . how a/c works
http://www.firstfives.org/faq/AC/ac_charge.html . . . how to charge using manifold set a lot like the one I was using. I'm just going to let the mechanics at my office deal with it. They offered to help me out and only charge for the freon. They said they would evacuate the system for me. I want to make sure everything is in working order before taking to him though. I do know the system is holding pressure with no problem. What would too much oil in the system do to it? Thanks for all the help!!

Ranger
08-09-10, 10:33 PM
Here is another good one.
http://www.autoacrepairs.com/index.html

miwise
08-09-10, 11:27 PM
Wow Ranger. That's a really good site. Thanks. :-)

miwise
08-09-10, 11:31 PM
I'm going to pull my orifice tube and see if I have the "black death." LOL. Hopefully all is well. I'll try and find an accumulator for it somewhere.

zonie77
08-14-10, 10:56 AM
I'm going to pull my orifice tube and see if I have the "black death." LOL. Hopefully all is well. I'll try and find an accumulator for it somewhere.


It would be good to watch them charge it. Once you see it done you get a good idea how to do it if you ever have to add some.

miwise
08-14-10, 07:04 PM
Yeah. I'm going to try. They will probably do it while I'm gone. I tried removing orifice to check but the dang thing is stuck! Couldn't get it out for the life in me. I even had the removal tool. No go. Tried some very small pliers that I was able to reach in with. Nothing. I wound up pulling it in half. I'll have to replace line I think. The dang thing is stuck.

Necrosan
08-15-10, 11:07 AM
I used a needle nose pliers.
If its that hard to remove it's probably installed incorrectly.. (Mine was, which also killed my low temperature sensor. Make sure you replace yours if the prong at the end is bent. Almost worth removing & checking so you don't need to re-evacuate to change it if it does end up being bad. It doesn't need to be pushed in there that hard/far, just far enough so that the other side of the line can clear it and far enough that the o-ring on the actual orifice tube is seated & sealing.)

miwise
08-15-10, 03:41 PM
I'll try checking that. Thx

mhamilton
08-16-10, 09:42 AM
If it broke in half and you can't get the rest out, I think there is a tool for extracting them. In a pinch, you might even be able to get it out by driving a screw into what remains of the old orifice. But be very careful, because that pipe that goes into the firewall is part of the evaporator, and I'm sure you don't want to get into replacing that (and you definitely don't want to get debris in the evap either!)