Air conditioning problem

A4x4Junky · 06-02-2006, 07:48 PM

Just purchased a 93 Limited this morning. Air didnt work, so I picked up a refill kit and went to work. Hooked up the hose and started to fill the system. Noticed that the pressure got up to the yellow (caution area), the compressor would cycle for about 2 seconds and the pressure would drop too low and the cutoff switch would do its thing. Over and over this was what happened.

Finally got fed up with this and jumped the compressor and proceeded to add 134. The needle stabilized towards the higher end of the full area. The air was cool, but rather disappointing. Removed the jumper and noticed that the pressure took off into the red

So, I can either lose 134 from the system and have the compressor not run because pressure drops off as soon as the compressor cycles, or I can allow the pressure to be in the red with the compressor not running.

Either way the air still is only cool...

Anthony

jeep_on · 06-02-2006, 08:54 PM

Well considering the system was never designed to run R-134a it will only blow cool air. If the system was recharged with R-12 as it was designed for, it will blow much colder air.

You may have a hard time finding R-12 in some places. You can also refill the system with some thing called Frezze-12. It is a direct replacement for R-12. Freeze-12 has a pressure curve which is close to R-12 while R-134a operates at significantly higher pressures than R-12.

cyberjedi · 06-02-2006, 09:43 PM

They do make a conversion kit from R-12 to 134a. My 93 GC had 134a it was cold. So I dont think that the only problem. Just an Idea

EMT · 06-02-2006, 11:16 PM

im assuming u have converted it from r 12 to r134?make sure your condenser isnt plugged with dirt and bugs and if that doesnt help start from scratch,pull a vacum and recharge.most people dont realize that when u run out of freon over time the freon is replaced with outside air and airconditioners dont work very good with air in the system.yes u can just put some refrigerant in and it will blow cool air but it wont ever blow cold until the outside air is purged from your system and replaced with refrigerant.

GreenDean · 06-02-2006, 11:32 PM

did you drain all the R12 out?

if you mix them it will goof up the performance of the system.

the only reall way to get all the old crap out is to have a garage throw a vacuum on it. AC is one of those things where sometimes it just pays to have a shop do it.

Edit.

oh and placing a vacuum on the system is the only real way to fill the system with new refridgerant without air getting in there.

cyberjedi · 06-03-2006, 12:39 AM

I forgot to say that don't mix r-12 and 134a and air in the system would make the pressure climb like that,

A4x4Junky · 06-03-2006, 04:31 AM

The Jeep was 134A from the factory, so that isnt a problem. I was afraid that the problem with the pressure climbing the way it is would be a byproduct of air in the system. While I dont mind having a shop do some things I dont feel comfortable with, I think I might just go and buy a pump and pull the vacuum myself.

Will see how that goes. Thanks for the advice.

Anthony

Turbonut · 06-03-2006, 04:46 AM

Quote:

Originally Posted by A4x4Junky

The Jeep was 134A from the factory, so that isnt a problem. I was afraid that the problem with the pressure climbing the way it is would be a byproduct of air in the system. While I dont mind having a shop do some things I dont feel comfortable with, I think I might just go and buy a pump and pull the vacuum myself.

Will see how that goes. Thanks for the advice.

Anthony

Yes it has 134 from the factory. Best to start fresh if the system was empty. Pull a vacuum and see if it holds @ 29". There must be a leak in the system as indicated by the low charge. The Jeep evaporators are a know problem. 3 out of the 4 ZJ's we've owned had to have the evap replaced, the forth was totaled before it rotted out. The orfice is another problem on the low side. Debris will contaiminate and clog the orfice and create problems also.

A4x4Junky · 06-03-2006, 04:51 AM

Thanks again for the information.

Anyone have a recommendation on where to buy a vacuum pump rated to hold 29? I keep seeing a bunch of air driven ones...but they dont guarantee 29...and 28 is about useless for what I need to do.

Anthony

EMT · 06-03-2006, 05:31 AM

go to your local place where everyone throws out their old appliances.(every town has that one spot) find a refrigerator or deepfreeze and pull the compressor and the pigtail.cut the hi side tubing 3 or 4 inches from the compressor and cut the suction side 3 or 4 inches after the valve(the one that u screw the guages on when u want to add freon)clamp the tubing on the suction side shut and fold it over on itself and solder it shut.just leave the hi side tubing open .wire the pigtail to the compressor.the compressor has 3 prongs one hot and one negative and i cant remember if the third is ground or not?. hook guage to suction on the compressor and to the low side of your a/c and plug in for an hour or so,then close the valves on your guages and see if it holds.

rwild · 06-03-2006, 05:37 AM

I have a commercial vacuum and it only draws to about -20lb and that has always worked great for me also anyone can but freeze 12 it is a replacement for R12 and its only about $10 a can and it is designed to blend with R12 so you can add it to a system that already has R12. Freeze 12 can be found at all Napa and Carquest store.