HELP HELP AC question for the smart one out there...

[fastback65chris]

$50 to anyone who can fix this.. AC question for the smart one out there...

I have a 1990 gt I had the R12 vacumed out and the old oil. I bought a retro fit kit r134a. I follow all the instructions and fill up the AC with my 134 bottles. The kit came with an inline guage. I filled the system up until the guage read charged my AC was ice cold and every thing seemed to be working fine when all of a sudden my engine starts knocking and acting like it is running on 2 cylinders. I reach in side to see almost 0 RPMs on the tach so I turn off the AC and my rpm goes back up and everything is normal. WTF!!!!! right? I get in the car drive it down the highway doing 65mph turn the AC on and the RPM dropps to 0 and the car almost dies on the highway. I immediatly turn the AC off and the car goes back to normal and bounces right back to 4500. "WTF" What in the hell in your ac system can drop your rpms from 4500 to almost 0 just by turning on the AC??? I plug in the guage and shows its charged just fine with the right amount of freon. I plugged the guage into my wifes care to make sure it was correct and it worked fine please please help me I am at a loss for answers.............

 

[ECU5.0]

did you put oil back into the system? if not im sure that is the problem...but ive never heard of a ac compressor without oil holding the engine back like that. it could be the a/c compressor is binding up because of now/low oil in the system and its grabbing your belt and putting a horrible strain on the motor. but thats just my opinion. maybe im way off

 

[fastback65chris]

the kit I bought had three cans with a mixture of oil and r134a in them

 

[ECU5.0]

you should probably get a different gauge. we sell those at advance auto...im assuming you got it there or autozone right? get one that actually reads pounds of pressure. im not sure, but i dont think those do. all cars take a different amount of freon depending on the size of the system. correct me if im wrong about the gauge though

 

[fastback65chris]

guage reads 42psi

 

[ECU5.0]

wow....ummm....last a/c system i did at work last summer took like 1.6 pounds of freon. not sure if thats 1.6 psi though. how many cans of freon did you put in it?

 

[jerry beach]

With the engine off, try turning your compressor by hand. Not the pulley, but the front part of it. You want to turn the clutch, and you dont need to take off the belt to do it. This will tell you if there is alot of resistance from the comp.

How did you "vacuum out all the old oil"? How long did it take you and what kind of pump did you use? Did you have a guage on it then? I pull a vacuum for at least 45min, then I let it sit for an hour or more to make sure it holds there.

 

[ECU5.0]

With the engine off, try turning your compressor by hand. Not the pulley, but the front part of it. You want to turn the clutch, and you dont need to take off the belt to do it. This will tell you if there is alot of resistance from the comp.

How did you "vacuum out all the old oil"? How long did it take you and what kind of pump did you use? Did you have a guage on it then? I pull a vacuum for at least 45min, then I let it sit for an hour or more to make sure it holds there.

yep...thats what youre supposed to do. pull a vacuum and make sure it holds. im thinkin there is too much pressure in the system

 

[Camman]

the only thing that happens when you turn on your ac is the compressor turning on(i know its not the ONLY thing, but the only thing that might affect rpm). If you hear a knocking sound that would be a HUGE flag for a bad compressor. Get a gauge set that connects to the high side as well, run the engine, record ambient temps, then record high/low side pressures and report back and we will be better able to rule the compressor out. Good luck

Edit: Follow mr. beach's suggestion first and see if you can turn the compressor by hand, then run the pressure test.

 

[fastback65chris]

thats whats wierd is the whole system barely took one can on the gauge it was reading into the red which is overcharging it so I purched it until it got down to the green which was the 42 psi mark my r6 sticker siad it took 2lbs which is 32oz when you do 134a your suppose to fill 80% so each can I had was 15 oz which meant it should of took almost two cans bit it didnt so WTF

 

[fastback65chris]

the compressor turns by hand just fine. What I found last night is when you turn the ac on and the car feels like its running on two cyclinders I turned my distributer to bump the timing and it worked just fine meaning it was running good and the car wasnt shaking at all but once I turned the car off and then tried to start it the car seamed lke the timing was so advanced that it wouldnt start at all it would just barely drag the starter. I turn the distributer back to normal timeing and the car starts right up I turn the ac on and it acts like its going back to two cylinders agian WTF? What temp readings do you want and what will a high pressure guage tell me. Also one other thing is that retrofit kit the fitting that fits on the low side is always open I screwed it to the compressor but once I filled it and pulled the adapter hose off that fitting was hissing like a big fat snake until I screwed the big blue cap on is that normal is that fitting suppose to be an open port all the time. I checked out my wifes Acura and hers doesnt his unless you release it manually what gives??? I'm at a complete loss here

 

[fastback65chris]

ok heres the deal I have spoken to three different air condioning shops and they are all telling me that I have a clog some where in my ac system. I did not change the orfice tube nor did I change the accumulator so I bought both items and I am going to go home tonight and change both items and see if I can find a clogg somewhere any other suggestions are welcome....

 

[rd]

I suggest properly emptying the system and having the condenser and evaporator flushed.

Then evacuate and refill with the correct amount of 134, generally about 2/3 the amount by weight of recommended 12.

Start and see if it works. Check the high and low sides of the system with gages and see what the pressures are.

If your system was empty because it was leaking or broken for a long period of time, the compressor may be corroded or filled with trash and gone, and it is time to change it.

That vintage of Ford has had some issues with the inner hose surfaces reacting with the refrigerant and oil and turning into crud that block the orifice and or compressor.

 

[rd]

I might as well add more of my experience with converting an 82 Bronco to 134. Initially the shop filled it with about 3/4 the amount recommended for r12. That gave me some of your symptoms, ie, very high head pressure at idle, poor cooling at idle. I did not experience the belt drag and engine slowing that you have, but the high head pressure blew oil past the compressor shaft seal, got it in the clutch, and the clutch began slipping at idle. Finally slipped a lot and I noticed it, and changed it. Ruined the second clutch, and I changed the compressor, and we reduced the charge to between half and 2/3 the amount listed for r12. Added an electric fan, and it worked like gangbusters for 6 years!

 

[1991vert]

if the system doesnt have enough fluid in it, the clutch wont grab. my compressor needs new o-rings and new fluid. and yes the clutch is supposed to grab when the a/c gets turned on, but mine doesnt grab either. they said it was some feature that if it's too low on freon, the clutch wont grab and spin.

 

[88mustangGT]

not to change topic but i am woundering what temp does everyoens vents put out?

 

[jrichker]

R134a Converstion on mine is 56-58 degrees after about 15 minutes of running

 

[88mustangGT]

i was about 62 after about 5 min still r12, i got that cheap lil ac check thing from checker and it says my system is a lil to full.

 

[fastback65chris]

I solved it I solved

Ok heres the deal I had my system vacumed down and it held a vacume just fine. So I went to autoparts store like everyone else did and bought an all in one retrofit kit with the adaptors gauge and cans. What I didnt have done is have all the old oil sucked out so I had the R12 oil still in my system when I started to fill the 134a. The box of crap I bought had three cans each can contained the 134a gas oil and some kind of leak stopper so when I went to recharge my system I could barley get one can introduced into my system without my compressor locking up and blowing sky high. So what should have been a little 30 buck deal has now turned into a 200 dollar nightmare. I bought a new liquid line, new accumulater with hose, three cans of 134a one can of oil, and I had to blow out all the old oil and have clean the oil out of the compressor and then have the system vacumed down again to check for leaks. What a son of a bitch. If I would have spent 15 bucks on 3 cans of r134a and just put the **** in there I would be driving around with ice cold ac and no credit card bill. R12 oil will work with 134a gas just fine I dont care who you are and what you say. All I needed to do was have the system vacumed down and dump the 134a in and I would have been done. One more thing those little all in one kits are a piece of ****.

Thanks for all your help

 

[k12]

I have a 1990 gt I had the R12 vacumed out and the old oil. . . .

Your first post said you had already had the old stuff removed?