ninjai_ruken

Ok, I have had an AC Problem since I picked up the car. I know the Compressor Works. But for some reason I can not get my System to take Refrigerant. I am starting to wonder if I have a blockage in my line. I can empty the system and start adding the refrigerant. The Pressure will start to rise in the system but I dont think its taking very much refrigerant. Seeing as it really wont blow cold air. One time the pressure on my gauge dropped to Zero and then started to climb again. So I started thinking maybe the system is clogged. Any suggestions?

beerwhiskeyjoe

When you say "empty the system" do you pull a vacuum? In addition to that, how to you know the compressor works? What are your low & high side pressures?

ninjai_ruken

I shouldn't say empty the system, I mean Decompress the System and Recharge it. Im not sure what the low and high are, all my tools are two hours away. The only thing I have had to go on so far is the gauge on the can of refrigerant/tube which reads in the green after I attempt to add some refrigerant. It acts like it is adding refrigerant like normal but I feel as if all it is doing as pressurizing the system while adding very little refrigerant. The AC does start to blow a little bit cooler but not much. I have checked and checked and there are no leaks in the system and it does hold a constant pressure. I can live without AC, but I have a 5yo daughter and I need to think about her comfort when temps reach a constant 90-110 degrees here in Montana

beerwhiskeyjoe

High side and low side means there are two different sides to the system- high pressure and low pressure side. To really diagnose whats going on you need to know both pressures, in addition to how those pressures relate to line temperature. Using those charging gauges really doesn't help with anything.

If you decompress the system to the point where its pressure is equal to atmospheric pressure (like if you just let refrigerant spew out until nothing more comes out) then you have air in the system and your a/c isn't going to work until you pull it down into a vacuum and then recharge it.

So can you see or hear the compressor clutch engaging at all? Also look at the belly of the compressor, is it dry or does it look wet like its seeping oil? How did your problem start out?

ninjai_ruken

It has been like this ever since I picked up the car two years ago. I knew how the High side and low Side are but thank you for explaining, I just don't have any tools with me and I don't have the money to take it to a shop. The clutch is engaging and the bottom is dry. I am thinking the previous owner might have done something to equalize the pressure. Any DIY info on pulling the system back down into a vacuum? I do have access to a few things. But my friend is a small time DIY'r with the basic tools in his garage. My dad and I have a shop full of tools back home. (Used to Race) Just cant afford to drive home right now. I am a Single Father, Going to School = Broke all the dang time..lol

ninjai_ruken

Yup Compressor Clutch is shot. It was engaging every time I looked at it. But I had my friend stand there and watch. He told me it engaged for a second then stopped. Damn it, I cant afford an new compressor. Are the ones out of a 3.4V6 swappable? The systems look almost identical.

ninjai_ruken

Ok, so I started thinking maybe my AC Relay was bad. So I went out started my car and pulled the fuse/relay box cover off. Fuse was good, turned my fog lights on. That relay fuse worked, so I pulled it out then pulled the AC Compressor relay and placed it in the fog lights spot. Lights didn't turn on so I started thinking GREAT! Maybe its a bad relay! Put the working relay in there with the AC on and the clutch still did not engage. I realize the clutch wont engage if the system is low. And right now I have no way of checking it. Which kind of sucks right now. If I had the cash I would just go buy a new compressor and get it over with.

fleetmgr

If you depressurized the system, you'll have to jump the clutch directly to the battery in order to recharge it. The LP switch is keeping it from engaging. Chances are that this will (temporarily) get you going.

ninjai_ruken

In your opinion whats the best way to jump it? I have done this on my GST but then again there is more room to work under that hood.

fleetmgr

Go to Radio Shack, they have pre-made leads with alligator clips on them. One to pos, one to neg. The other ends on the terminals for the compressor and you're good to go.

ninjai_ruken

LoL, I was more hinting on the fact that the terminal is not an easy place to reach. I made some tonight with clips and tried to get in there but couldn't reached so I am going to have to remove some stuff.

fleetmgr

Ah, sorry! No offense meant!

ninjai_ruken

Its cool, lol

slow

iTrader: (7)

use a piece of wire and jump the compressor relay at the fuse box, or using tuning software or a tech2 command the AC clutch on.

Using the recharge by liquid on the high side method, after pulling a vacuum, you will likely not have to jump the compressor. Autozone rents (free after return) a vacuum pump and manifold gauges (some do not, but around here they do) discharge the system, pull a vacuum and recharge to the correct amount.

Ryan

Texhotrod593

iTrader: (7)

he is right about the lending tools from some well known auto parts distributers. I have read the whole thread and something still seems wrong.... I mean yeah, the proper way is to pull a vacuum and yeah, you def need gauges but the compressor clutch in and out? i dont think its going to be a compressor clutch....you havent given us any pressures to tell whats going on and not much of a background on how the system became such a monster.THE MOST IMPORTANT TOOL FOR ANY TYPE OF REFRIGERATION ARE GAUGES, PERIOD! It almost sounds like to me there are non-condensables(water,nitrogen,oxygen etc..) in the system, more so prob water. A GOOD vacuum can take care of this more than likely. It also sounds as if the orfice could be stopped up as it could be dropping the suction pressure to the point the LP switch de-energizes the clutch to keep from pulling the system into a vacuum. The orfice stopping up could be do to icing up from water in the system or just plain 'stopped up with trash'. No matter how much refrigerant you have or can stack into a system, if it cant "suck" the refrigerant through the evaporator it will never work.

Ok, that being said, break down... compressor= air pump, evaporator=heat exchanger(heat absorbing), condensor=heat exchanger(heat disapating) expansion device(orfice tube)=pressure reduction(also to break the solid liquid form to approx 25%gas and 75%liquid) and then a few switches and relays mainly for safety for the system.

It sounds like your comprssor is working fine...other than that, we know nothing. pressures tell us the whole story how your system is working. Do not worry about relay, switches, rigging clutch solenoids etc until you go "borrow" some gauges and tell us what the pressures are doing both on the suction and the head sides. If you can give me the pressures and what they are doing at throughout the whole time then I can prob be able to tell whats going on. I wanna help you out! get back soon with pressures

Texhotrod593

iTrader: (7)

There, I fixed it for you

slow

iTrader: (7)

are you sure on your correction?

I have always been told no liquid on the low side or you will damage the compressor when it tries to compress the liquid. Charging by liquid (engine off, in a vacuum state) on the high side is ok. Or just charge by vapor on the low side.

When the system is running you always want to charge vapor on the low side. (high side closed on your manifold gauge set)

Ryan

Texhotrod593

iTrader: (7)

yes...sorry i misunderstood the intention there. I slapped my hand for that! If your not calling for cool and you have a vacuum then yes, you can dump plenty of liquid to fill the system b4 you start it up. When you have some refrigerant in the system and it stops pulling refrigerant in then close the high side, start it the car and "meter" the refrigerant in by liquid on the low side or to be extra safe, just use the system on the low side to pull the refrigerant in by gas. If the refrigerant wont move out of the can well, just stick the can down in hot water and that should help.

slow

iTrader: (7)

no problem, just didn't want somebody to read this and dump full liquid into the low size and boom the compressor, by not metering the charge.

Ryan

fleetmgr

In the normal course of events, there is no set of conditions that will put an R-134a A/C system into a vacuum, for a couple of reasons:
1. The LP switch won't allow it.
2. You'd have to be in an ambient temperature of -25 degrees farenheit, with the engine off.

A key thing to remeber about any refrigeration system (A/C is a refrigeration system) is that pressure = temperature, and vice versa. This assumes a "pure" system, with no air or other non-condensible gasses present. Doesn't matter if it's R-134a, R-12 or
R anything else....pressure = temperature & temperature = pressure.

The reason you can't get refrigerant to flow from a can into the system with the system off is because the pressure in the can, and the pressure in the system are too nearly equal. You can heat the can in water, as was mentioned...or you can get the system to run.
You should NEVER hook a can of refrigerant to the high side with the system either running, or having been run in the last 30 minutes or so. You could easily exceed the burst pressure of the can by doing so.