air conditioning problem?
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air conditioning problem?
i got an 03 hemi ram and its got about 105,000 miles on it and the ac just started messing up one day, the A/C compressor just started cycleing on and off and the air wont get cold anymore so natrualy i thought it was low on R134 so i try to put some in and it wont take anymore, i also hear a hissing sound that sounds like its leaking from the A/C lines on the passanger side firewall
also to day at work a customer came in with a 07 hemi durango with 18 miles on it and it already did the same thing we put in a big can of R134 and it didnt fix the problem so lucky him its still under warrenty but not our truck
so i was wondering if anyone else has had the same problem and how did yall fix it?
also to day at work a customer came in with a 07 hemi durango with 18 miles on it and it already did the same thing we put in a big can of R134 and it didnt fix the problem so lucky him its still under warrenty but not our truck
so i was wondering if anyone else has had the same problem and how did yall fix it?
RE: air conditioning problem?
You really need to download the FSM manual for your truck. The answer is in there.
You have two sensors on the a/c system, one that monitors temps on the evaporator coil, and a transducer that feeds pressure info back to the PCM. If the system hits 460 psi, yes, thats 4-hundred, 60-----the PCM cuts the compressor, and if the evap gets too cold, it does the same. If you add too much refrigerant to the system, and it shouldn't have to if there are no leaks, then its a possibility that the sensors are feeding false info to the PCM, or, the a/c condenser coil fan, in the engine compartment isn't working, or the evap coil under the dash may be blocked, or the resistor pack that controls the blower fan speeds is giving you problems. It ain't like the old days-----see ya'------ All the stuff is run by a computer now. Now we just have to learn how to talk to the monster!!!
If you have been adding r-134a to your system, and there is no leaks, you have flooded the system. This will pull all the lubricant out of the compressor, and send through the entire system, also raise the discharge pressure to the 460 mark. Plus, because the system is overcharged, the cooling will be reduced, as you add more to the overcharge.
You are dealing with some technical stuff concerning the temperature/pressure relationship of gasses under pressure and very high velocity. At this point, I strongly recommend you hook up with someone that really knows what they are doing. To bring your system back to where it belongs, will require some careful removal of the excess gas without the removal of the oil, until the system is in a deep vacuum, 50 micron or less, and then weight the refrigerant charge back in to the correct weight for the system.
Sorry this is so long, but you really need to know what you are dealing with here
You have two sensors on the a/c system, one that monitors temps on the evaporator coil, and a transducer that feeds pressure info back to the PCM. If the system hits 460 psi, yes, thats 4-hundred, 60-----the PCM cuts the compressor, and if the evap gets too cold, it does the same. If you add too much refrigerant to the system, and it shouldn't have to if there are no leaks, then its a possibility that the sensors are feeding false info to the PCM, or, the a/c condenser coil fan, in the engine compartment isn't working, or the evap coil under the dash may be blocked, or the resistor pack that controls the blower fan speeds is giving you problems. It ain't like the old days-----see ya'------ All the stuff is run by a computer now. Now we just have to learn how to talk to the monster!!!
If you have been adding r-134a to your system, and there is no leaks, you have flooded the system. This will pull all the lubricant out of the compressor, and send through the entire system, also raise the discharge pressure to the 460 mark. Plus, because the system is overcharged, the cooling will be reduced, as you add more to the overcharge.
You are dealing with some technical stuff concerning the temperature/pressure relationship of gasses under pressure and very high velocity. At this point, I strongly recommend you hook up with someone that really knows what they are doing. To bring your system back to where it belongs, will require some careful removal of the excess gas without the removal of the oil, until the system is in a deep vacuum, 50 micron or less, and then weight the refrigerant charge back in to the correct weight for the system.
Sorry this is so long, but you really need to know what you are dealing with here
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RE: air conditioning problem?
wow that sucks, but no i havent added or taken away any r134 i only put one of those universal gauges to see where the pressure was at but the gauge just goes up and down while the compessor turns off and on, and i still dont know where the hissing noise is comming from it only happens when the compressor starts cutting off and on
RE: air conditioning problem?
From the sounds of the cycling, and you haven't added any refrigerant to the system----there is a fair chance that you have developed a leak in the system, but, before you add any, check these things first. (1) is the condenser fan running when you turn the a/c on? The small one to the right of the large fan, if not, good suspect. In this weather, it should be running when you start the a/c. (2) Is the condenser coil clean, also next to the right of the radiator. (3) Ok, the high pressure transducer is located in the engine compartment, on the refrigerant liquid line. To determine which is which, its the smaller line going into the duct system throught the firewall.It is located on the outlet line at the compressor. It sends a signal to the pcm for control by the computer. Can't mess with it.
If the fan isn't running, check to see if you have 12v going to it, also check the fuse for it. If there is voltage, then the fan should be running, and isn't, time to get a new one.
The other sensor, is actually a temp sensor mounted on the coil inside the air distribution box inside---no way to get to it. To properly diagnose that, would require a scanner in the drbIII configuration. In short, you can't mess with that.
If all the above checks out, the most likely problem is that you have lost a very small amount of refrigerant causing the coil to freeze, and thus the computer is cutting it out. In this case I would suggest adding a very small amount of 134a. Not a full can!!!!!!! If you add a small amount,with the inside fan on high, and no recirc, drivers and passenger doors wide open, and the compresor comes up and continues to run, you have two options, (1) hook up with someone with an electronic leak detector for refrigerant, and find the leak and repair it. Then have the system recharged to the proper weight using the specified amount on the tag in the engine compartment. (2). Add a small amount when necessary, realizing that if you introduce any air into the system---at all, you will over a period of time, destroy the system and require a full system flush and replacement of some of the system components, including the fried compressor.
The refrigerant needs to be added to the low pressure line in the system, if you hook the can to the high pressure line, you will actually pump refrig into the can, and in all likeleyhood, explode the can---you don't want to be anywhere near when it happens. You'll be headed for the hospital if your lucky.
If your are using one of those kits that you get from autozone--or wherever, then it will only hook up to the low side line.
Good Luck,
Do you wonder why this stuff is so expensive to repair these days?
If the fan isn't running, check to see if you have 12v going to it, also check the fuse for it. If there is voltage, then the fan should be running, and isn't, time to get a new one.
The other sensor, is actually a temp sensor mounted on the coil inside the air distribution box inside---no way to get to it. To properly diagnose that, would require a scanner in the drbIII configuration. In short, you can't mess with that.
If all the above checks out, the most likely problem is that you have lost a very small amount of refrigerant causing the coil to freeze, and thus the computer is cutting it out. In this case I would suggest adding a very small amount of 134a. Not a full can!!!!!!! If you add a small amount,with the inside fan on high, and no recirc, drivers and passenger doors wide open, and the compresor comes up and continues to run, you have two options, (1) hook up with someone with an electronic leak detector for refrigerant, and find the leak and repair it. Then have the system recharged to the proper weight using the specified amount on the tag in the engine compartment. (2). Add a small amount when necessary, realizing that if you introduce any air into the system---at all, you will over a period of time, destroy the system and require a full system flush and replacement of some of the system components, including the fried compressor.
The refrigerant needs to be added to the low pressure line in the system, if you hook the can to the high pressure line, you will actually pump refrig into the can, and in all likeleyhood, explode the can---you don't want to be anywhere near when it happens. You'll be headed for the hospital if your lucky.
If your are using one of those kits that you get from autozone--or wherever, then it will only hook up to the low side line.
Good Luck,
Do you wonder why this stuff is so expensive to repair these days?
Champion
Joined: Nov 2005
Posts: 2,875
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From: North Eastern England
RE: air conditioning problem?
WOW GoneFishin.........I don't even have an AC problem, but I found all of that very interesting.
As you say, need to figure a way to "talk to the monster". The monster being the computer.
I remember a very old saying, "don't fit it if you can't fix it"................That certainly doesn't apply to vehicles these days eh?[sm=confused06.gif]
Al.
As you say, need to figure a way to "talk to the monster". The monster being the computer.
I remember a very old saying, "don't fit it if you can't fix it"................That certainly doesn't apply to vehicles these days eh?[sm=confused06.gif]
Al.