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Discussion Starter #1
Ok so what should be the first step in getting my A/C to work. The A/C compressor turns on but shut for a second at a time or so. No cold air It has been converted to R-134a.

I have a bunch of tools but nothing for A/C work
Thanks
 

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I can't say what your ABSOLUTE first thing should be, but one of the first things should be to have a vacuum and pressure test performed on the whole system. All of your components (compressor, reciever, drier, condenser, etc) could be working fine, but if your seals are shot or you have a leak. Nothing will work.
 

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Discussion Starter #3
That's what I was thinking but I was trying to keep from having to go to a shop. But I might not be that lucky. :sheep:
 

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I know what you mean. You should be able to remove and replace all the parts yourself, but testing and servicing needs to be done at a shop or by someone who has all of the equipment. Especially when it is time to service with refrigerant. You want a vacuum in the system when you charge it. That's something you only get when you have a pro servicing cart hooked up to it.
 

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Ok so what should be the first step in getting my A/C to work. The A/C compressor turns on but shut for a second at a time or so. No cold air It has been converted to R-134a.

I have a bunch of tools but nothing for A/C work
Thanks
when the a/c system has low pressure or no pressure the compressor shuts down and starts ... test if you have a leak if you don’t the pressure in the can will help it
 

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The first thing you should do is a pressure test with nitrogen at 100 psi. Once you reach 100 psi, isolate the nitrogen bottle from the system, turning the valve on the N2 bottle should suffice, it should hold for at least an hour with no movement of the pressure needle. Place a mark the gauge face. If you pass that test then evacuate the system with a vacuum pump, for at least 45 minutes, to a vacuum of at least 29.5 " Hg. With the vacuum pump off , the system should hold 29.5" Hg. for at least 20 Min with no change in pressure. You need to isolate the pump from the system when checking to see if the vacuum holds or it will pull past the vac. pump. If you pass that test then your system has no leaks. You should add approx. 80 to 90% of the original charge weight to the system. There is a sticker on the compressor or evaporator case that tells you the original charge weight. Take 80 to 90 % of that weight and add to the system. Leave the system under a vacuum and add the 134A Ref. to the system. The vacuum will pull most of the 134a in the system. The remaining refrig. will have to be added after you start the car. The best and only way to add refrigerant to the system is by weighing the charge using a scale. You cannot rely on the gauges to tell you if the system is fully charged.

Also, you say the system was converted to 134a, to do this the drier should have been changed, the system should have been flushed to remove the mineral oil and replaced with Pag oil. If your system has an orifice tube, then the pressure switch needs to be replaced with one calibrated for use with 134a (it has different cut-in and cut-out pressures than R-12) If you have a TXV (thermal exspansion valve) you may have to adjust it (some TXV's are not adjustable though) Yeah I know it's alot of work and you need alot of equipment. Sometimes it's best to take it to a professional. Personally, I like to do all my own work that way I don't have to rely on someone else and when I'm done I know it's right!
 

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The first thing you should do is a pressure test with nitrogen at 100 psi. Once you reach 100 psi, isolate the nitrogen bottle from the system, turning the valve on the N2 bottle should suffice, it should hold for at least an hour with no movement of the pressure needle. Place a mark the gauge face. If you pass that test then evacuate the system with a vacuum pump, for at least 45 minutes, to a vacuum of at least 29.5 " Hg. With the vacuum pump off , the system should hold 29.5" Hg. for at least 20 Min with no change in pressure. You need to isolate the pump from the system when checking to see if the vacuum holds or it will pull past the vac. pump. If you pass that test then your system has no leaks. You should add approx. 80 to 90% of the original charge weight to the system. There is a sticker on the compressor or evaporator case that tells you the original charge weight. Take 80 to 90 % of that weight and add to the system. Leave the system under a vacuum and add the 134A Ref. to the system. The vacuum will pull most of the 134a in the system. The remaining refrig. will have to be added after you start the car. The best and only way to add refrigerant to the system is by weighing the charge using a scale. You cannot rely on the gauges to tell you if the system is fully charged.

Also, you say the system was converted to 134a, to do this the drier should have been changed, the system should have been flushed to remove the mineral oil and replaced with Pag oil. If your system has an orifice tube, then the pressure switch needs to be replaced with one calibrated for use with 134a (it has different cut-in and cut-out pressures than R-12) If you have a TXV (thermal exspansion valve) you may have to adjust it (some TXV's are not adjustable though) Yeah I know it's alot of work and you need alot of equipment. Sometimes it's best to take it to a professional. Personally, I like to do all my own work that way I don't have to rely on someone else and when I'm done I know it's right!
good advise
 

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Discussion Starter #9
I don't have any of that equipment. So I think I'll just try the recharger thing. If it doesn't work I'll send it to a pro. A really good friend of mine is a Manager at a shop and I know he'll take good care of me and my car!!
 

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Discussion Starter #10
Well I put a can in and it worked. As soon as I put it in the compressor stayed on. It took nearly the whole can. The only problem I really found was the electric fan wouldn't turn on. Any ideas about that?

Thanks
 

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I know its simple, but I did all the looking and checking and in the end found the wiring harness melted and the motor got no power ( on 78-82 the hot is a purple wire for the blower motor)
 

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Discussion Starter #13 (Edited)
Ok so fuse was good I jumped the motor and the motor is good. I followed the motor back and it plugged into a light blue and black wire. Black wire tested good for ground. Followed LB wire back and it tied in with the rest of the A/C wiring that went back to a big plug in. Cleaned and made sure it was pluged in all the way. Looked after the plug in and it looks like a bunch of wires goes somewhere down by the starter. Then I see this wire that's black and blue that looks like it needs to be plugged in. Come to find out it is the electric fan wire. I looked around and see no place to plug it in. I looked in the manual and that is no good at all. It doesn't even hardly mention the electric fan. So here the pic. Hope you can see.




 

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Discussion Starter #17
So I thought I should take more pics

So this pic is under the car. I don't see anywhere to plug this in at.



(off topic) but what is this for? It's on the pass side
 

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it might be the ground for the relay and the the blue wire is for high on the relay (this is only a theory in the morning I can look at my car to see)
in the next pic cant see where the hose comes from, but the only hoses i know is the heater and the a/c
 

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Discussion Starter #19
The last pic. Is behind the header. On the left is the spark plug. I think it's some kind of knock sensor or something.

I'd appreciate you looking please. Thanks!!!!
 

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I looked but found no blue wiring do you know if might have been replaced and the color code does not match? the two prong wiring I saw was for the solenoid in that area
 
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