Howdy,

I have 93 7.3L diesel, I am trying to charge up the AC. I replaced the drier and put about 2 1/2 oz. of pag in it like your supposed to. I replaced the orifice tube with with a red one just like the one that was in it, one thing I noticed when replaced it, the new one wouldn't go in the tube as far as the old one did. The old one went in and about a 1/4'' below the top of the tube, and the new one stuck out of the tube by about 1/2'' or so. They both look the same, I double checked with the parts guys to make sure it was the right one, and it was so I don't know if that's a problem or not. The line that hooks up to the orifice tube went on just fine. I vacuumed the system out for about 90 minutes to make sure there was no moisture left in the system. I turned off the pump and let it sit there for about ten minutes and then checked to make sure the vacuum held. I then hooked my can tap up with a can of 134a, I opened up the low side to let some freon into the system, it took a little freon, I then closed the low side and started the truck up and turned the AC on high. The compressor did not come on, so I opened up the low side to let more freon in but it wouldn't take anymore. I then jumped the pressure switch out so the compressor would come on, and that worked so I opened up the low side to let more freon in. It took a little more freon and that was about it. I hooked the pressure switch back up and it started cycling. I don't even think it took a 1/4 of a can. The ambient temp was 76, the high side pressure was fluctuating between 100 and 125 psi as the compressor cycled, the low side would go up to 45 psi then the compressor would cycle on and the pressure would fall to 30 psi and the pump would cycle off. The compressor would stay on for about 1 second, and off for about 3-5 seconds.
Sorry for such a long post, but I wanted to try to give as much info as I could.
Any help would be greatly appreciated.

Thanks,
Gr8ride

 

was the truck r12 to start with? in canada 93 was the last year for r12. i ask because if you had to use retrofit fittings mabye the low side fitting is no good, had this happen a few times at work. also is it possible the tube is put in backwards, no offence meant but i have seen it done.

 

I guess I did forget to mention that it was R12 and I am converting to 134a. I will check the orifice to see if I put it in upside down. Just to refresh my memory which end of the orifice goes in first?

 

the end with the large screen will face towards the condenser. most also have a arrow that points in the direction of flow of the freon.

 

Thanks cheez67, that's what I thought. I am pretty sure I put in like that but I will find out, tomorrow it will be warm enough that I can try to charge it again.
Happy new year.

 

if the tube is in correct then check the adapters. did you remove the old scharder valves before installing the adapters? some adapters use the old vavles and some do not. if this is not the problem my next suggestion may sound alittle simple but are charging on the low side? i think on your truck the place to fill is on the accumulater, hope all this helps. also are you filling in the cold? if so it may be as simple as low pressure in the can of r134, you try wrapping a warm towel around the can when charging, good luck.

 

Turned out to be the right package but the wrong orifice tube in that package. Once I got the right one in it,it charged up pretty good. Thanks for the tip about using the warm towel on the can, it helped a lot.

Thanks again,
Gr8ride