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Discussion Starter · #1 ·
2001 ODYSSEY LX, DUAL AIR, Note, I have a complete service manual.
A/C started blowing hot air, took it to A/C shop (free diagnoses), they said it was out of refrigerant needed to be evacuated and recharged $150. I think it had some refrigerant in it (maybe they let it out) because the compressor would run before I took it to them which I believe to run it requires pressure in the system.
Here is what I have done so far...
I evacuated system for 30 minutes, both low and high sides then held the max vacuum for another 30 minutes, then I hooked up refrigerant can, blead line from can to gauges, opened both valves, system started recharging, after pressure in can and system equalized (40+ psi), I closed hi side valve, started engine with fan speeds both on high, max cold and a/c on but compressor did not run, turned off engine, removed compressor clutch relay (in fuse box) and jumped it, started engine and compressor started drawing in refrigerant but stopped after 257 grams (9.07 oz of the 12 oz can), called auto parts a/c guy he thought it might be the can's valve, so I hooked up a second can but system quit taking refrigerant at 80 grams (about 2.8 oz), air still blows hot, dual a/c takes 850-900 grams (30-31.7 oz), system now has 337 grams (11.89 oz), the low side pressure is 65 psi (too high) and the high side pressure is 55 psi (way to low). There are no apparent leaks, the system holds a vacuum, everything looks ok.
Any help will be greatly appreciated.
Thank you
 

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How do you know it stopped takes R134? It can go in really slow. Was the R134 can cold? If it was still cold then the R134 was evaporating in the can and going into the system.
 

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Discussion Starter · #3 ·
Thank you for the reply.
Both gauges stayed at the exact same pressure for well over a half hour.
I tried shaking the can and the low side pressure would go up maybe 5 psi, but when I stopped shaking the can, a minute or two latter the pressure would go back to where it was before. I would guess I gave up on the first can after an hour and half, and the second can after an hour.
 

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what are your line pressures with the system running?

another informative thread.

 

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Discussion Starter · #7 ·
did not check the inlet temperature
the outside temperature is 89 and humidity is 48%, it was probably 5 degrees cooler when I was trying to add refrigerant
 

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Those pressures don't look right. High side is always higher pressure than the low side. The low side pressure is too high.
Sometimes I find that if I get odd behavior, simply turning the AC off for a few minutes and back on will help.
When you rev the engine does the low pressure reading go lower? Like to 20, 10 or even 0?
It may be that the expansion valve is having a problem.
 

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Discussion Starter · #9 ·
Turned the a/c off several times trying to get the refrigerant in, no change, did not try revving the engine, I'll have to hook everything back up and let you know later.
In the mean time is there a way to check or bypass the expansion valve so I can get the refrigerant loaded?
 

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It sounds like your high pressure line was open when you started charging with the first can of refrigerant. You only charge on the low side. Never on the high side. And you charge with the car and ac running. What you should have done was....After the system held the vacuum for half hour, you close both low and high side at manifold end. Disconnect vacuum pump and connect can of r-134a on yellow middle hose. Then, let off some refrigerant to load the yellow hose at manifold end. Then start the car and AC-also the rear ac. Only then you open the low pressure side to charge the refrigerant into your ac. The vacuum in the system will suck in the refrigerant from the can without any problems. Flip the can upside down-hose end down- to help it go in. shaking the can also help.

At this point, I would redo the vacuum pump and charge the ac the correct way. You will need close to 3 12 oz cans. Make sure to always load the yellow hose and let off some refrigerant each time you change cans. This will eliminate the overcharging of the system.
 

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Discussion Starter · #11 ·
Thank you for your reply. I understand that you should only charge the system from the low side when the car is running as charging the high side can produce an explosive psi that can blow up the refrigerant container and destroy the ac system. Opening the high side when the car is NOT running only charges the low and high systems to the pressure of the can about 40 psi which is no danger, at that point only about 3 oz of refrigerant went into the system which should not have been a problem. I did not turn the can upside down as that sucks in liquid, not vapor and if that liquid doesn't vaporize before entering the compressor it can destroy it. I blead the line at the manifold. If you know for sure that putting 40 psi on the high side is the problem please let me know how and why.
 

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did not check the inlet temperature
the outside temperature is 89 and humidity is 48%, it was probably 5 degrees cooler when I was trying to add refrigerant
inlet is the outside / ambient temp, and I concur with those pressures.
provided you have the right amount of gas in there.

dealing with my own AC issues on my acura, the damn clutch wont engage.
 

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Thank you for your reply. I understand that you should only charge the system from the low side when the car is running as charging the high side can produce an explosive psi that can blow up the refrigerant container and destroy the ac system. Opening the high side when the car is NOT running only charges the low and high systems to the pressure of the can about 40 psi which is no danger, at that point only about 3 oz of refrigerant went into the system which should not have been a problem. I did not turn the can upside down as that sucks in liquid, not vapor and if that liquid doesn't vaporize before entering the compressor it can destroy it. I blead the line at the manifold. If you know for sure that putting 40 psi on the high side is the problem please let me know how and why.
I see 2 errors here. You only charge on the low side, never on the high side, with the car and ac running. Doing it any other way is not how its done ( according to the FSM or any instructions I have read) when charging your car AC system. Never done it any other way. Never had a problem. When charging on the low side, all the contents of the r-134a can, liquid or gas state, is not a problem.
 

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Discussion Starter · #14 ·
inlet is the outside / ambient temp, and I concur with those pressures.
provided you have the right amount of gas in there.

dealing with my own AC issues on my acura, the damn clutch wont engage.
Not sure what you mean by "I concur with those pressures", my low side is too high and my high side is way low.
I do NOT have the right amount of gas in there, I only have about 1/3, that is the purpose of this post, to get the rest of the refrigerant in.
 

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You cannot charge a system simply based on pressures.
 

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Discussion Starter · #16 ·
You cannot charge a system simply based on pressures.
Not sure what you are saying.
After evac I can only get 11.89 oz in the system that takes 30-31.7 oz
The pressures are what the gauge showed last, 65 on the low (too high) and 55 on the high (way to low)
If you have any thoughts on how I can't get the needed refrigerant into the system (still short 18+ oz) I would greatly appreciate it.
 

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Your high/low pressures are so close (within gauge error) I think you may just have a failed compressor. In any case, you have a system problem that will require disassembly, replacement of parts, vac & recharge. Just trying to get more charge in is a waste. You are above LPCO setting. I use a bucket of very warm water to heat the can so it empties into the system.
 
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Maybe one 12 oz can may not be enough to get the compressor kicking on but 2 cans probably will.
You only want to add enough refrigerant so the compressor will engage. Then you can get a reading on whats going on. If you see the compressor is already engaging on the first can, then, the reading you are getting is what it is. And you have a part failure to compress.
 

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Discussion Starter · #19 ·
Maybe one 12 oz can may not be enough to get the compressor kicking on but 2 cans probably will.
You only want to add enough refrigerant so the compressor will engage. Then you can get a reading on whats going on. If you see the compressor is already engaging on the first can, then, the reading you are getting is what it is. And you have a part failure to compress.
Thanks for the reply.
The compressor did not run when I started the car, I stopped the car, jumped the relay and restarted the car and the compressor ran sucking in about 10 more oz of refrigerant.
The compressor was still running when I quit, but I still can't get the rest of the refrigerant in.
 

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Discussion Starter · #20 ·
Your high/low pressures are so close (within gauge error) I think you may just have a failed compressor. In any case, you have a system problem that will require disassembly, replacement of parts, vac & recharge. Just trying to get more charge in is a waste. You are above LPCO setting. I use a bucket of very warm water to heat the can so it empties into the system.
How can I determine if the compressor is bad?
 
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