Problem with AC charging

[nsxblack]

I have a 91 and the AC doesn't blow cold. I read several threads here with people charging their own AC, so I gave it a try.

The first thing I did was to buy new fittings to accommodate the R134 refrigerant. I screwed the new fittings on fine. Then I hooked up the pressure gauge to read the low side. It was at 0. With the engine and AC running, I started to inject the refrigerant. However, after only about 6 seconds, the gauge reads 35 psi and in the green zone. Therefore, I stopped. I checked the vents, and it still blows warm. Also, hardly any refrigerant went into the system, but it reads full. Any idea what is wrong? For sure there is not enough refrigerant in the system, but I don't want to inject more until I get some advice. Thanks.

 

[SoCalDude]

I have a 91 and the AC doesn't blow cold. I read several threads here with people charging their own AC, so I gave it a try.

The first thing I did was to buy new fittings to accommodate the R134 refrigerant. I screwed the new fittings on fine. Then I hooked up the pressure gauge to read the low side. It was at 0. With the engine and AC running, I started to inject the refrigerant. However, after only about 6 seconds, the gauge reads 35 psi and in the green zone. Therefore, I stopped. I checked the vents, and it still blows warm. Also, hardly any refrigerant went into the system, but it reads full. Any idea what is wrong? For sure there is not enough refrigerant in the system, but I don't want to inject more until I get some advice. Thanks.

Has the AC system on your 91 been converted to R134 because it came with R12 from the factory?

 

[nsxblack]

No, I don't think it has been converted. That's why I bought the new R134 fittings and installed them. Anything else that would need to be retrofitted?

 

[SoCalDude]

No, I don't think it has been converted. That's why I bought the new R134 fittings and installed them. Anything else that would need to be retrofitted?

Not sure but I hope you drained the R12 before putting in the R-134. I had my system retrofitted but I didn't do the work myself.

Here's some info.

TSB 92-027

 

[rbirling]

Did you evacuate the system first?

 

[nsxblack]

There was nothing left in the system before I got started. The pressure gauge read "0".

 

[shawn110975]

you need to make sure your system is empty

I did the same thing. mine works perfect. for almost a year and a half now

you need to make sure to start at empty. well mine was empty when i started

one way but its illegal is press the valve on your system intill all pressure has been released. it is bad for the OZONE but if you can sleep at night
knowing you did it So can I.

then while the car is running turn the ac on

while charging the system the stupid cheapo gauge will say green is charged. and the yellow is over charged, and the red danger.

I stopped at the green also still no cold air. so I kept charging it got it up to the 42 psi mark almost to the red. and my passengerside was ice cold but not my driver side. so I kept charging it till both sides blow ICE cold. and I stopped filling it.

I think the cheapo gauge that comes with the kits are not very accurate

my kit was like 89 bucks for the gauge 3 cans of R134a and a Must watch User DVD

PM me if you want more detailed instructions

5 people have called me and I walked them thru it and they thanked me

 

[nsxblack]

shawn110975, sounds like you had the same problem I did. I will PM you for detailed instruction. Before charging, I did press that pin down to see if there was anything left in there, and nothing came out. My cheapo gauge reads about 40 and on the high side of green. However, I used only about 1/10 of the 12 oz refrigerant can.

 

[rbirling]

Does the pressure gauge read 0 when not connected to anything? If you opened the system, there is air and water vapor in there. I wouldn't expected it to work very well till you pump that all out to a vacuum. Maybe if you did it fast you might get by with it, but I thought you also changed from R12 to R134. You'd need to make sure there's no R12 left in there either.

There was nothing left in the system before I got started. The pressure gauge read "0".

 

[nsxblack]

Yes, the gauge reads "0" when not connected to anything. It also read "0" when I initially connected it to the Low side line.

 

[danny49]

Your reciever dryer is clogged, You have to replace it and evacuate the system Best to have a AC guy do it.

 

[Daedalus]

Good way to destroy the compressor. Not sure if you added the right type and the right amount of oil for the R-134a. Also, what did you do with the old R-12 oil still sitting in the lines and the receiver? It isn't soluble in R-134a and can hydrolock the compressor if enough is ingested.

 

[Doc308]

I had my system converted a couple of yeas ago and the mechanic insisted that I replace the receiver dryer as part of the process to insure that the old freon was totally evacuated from the system. The evacuation process took quite a while if I remember correctly.

 

[nsxblack]

Thanks everyone for your input. I had an extra person helping me turn on the AC while I put my ear near the compressor. It did not turn on with the clicking sound. This is the start of the problem. I will look further into it.