1990 Escort A/C - Not Cold at Idle

[frafreg]

My a/c compressor seized up last year so I replaced everything. That includes the clutch, the compressor, the orifice which is the entire hose with the orifice inside, and the accumulator which also includes the hoses as part of the assembly. I flushed out the condenser and the evaporator, replaced all of the seals, replaced the gaskets on the compressor and added 6 ounces of oil. I evacuated the system and charged the system with R134. I did everything according the book. It blows cold air when I'm on the highway but not so cold when I'm stuck in traffic. I can see that the compressor is engaged at idle and the clutch is not slipping. I replaced the belt to make sure it wasn't slipping. When I put the gauges on it, the high and low pressure reading at idle are both low, until I raise the idle to about 1200 rpms. Then, the high and low pressure readings go into the normal range and it starts blowing cold air. How can I tell if the compressor is bad or maybe the orifice is clogged or the system still has air in it? This is frustrating because I always do everything by the book to avoid problems like this one. Thank you in advance for any help. I appreciate it.

[brcidd]

Is your cooling fan working?

[frafreg]

Originally Posted by brcidd

Is your cooling fan working?

Yes, the fan works good.

[frafreg]

Originally Posted by frafreg

My a/c compressor seized up last year so I replaced everything. That includes the clutch, the compressor, the orifice which is the entire hose with the orifice inside, and the accumulator which also includes the hoses as part of the assembly. I flushed out the condenser and the evaporator, replaced all of the seals, replaced the gaskets on the compressor and added 6 ounces of oil. I evacuated the system and charged the system with R134. I did everything according the book. It blows cold air when I'm on the highway but not so cold when I'm stuck in traffic. I can see that the compressor is engaged at idle and the clutch is not slipping. I replaced the belt to make sure it wasn't slipping. When I put the gauges on it, the high and low pressure reading at idle are both low, until I raise the idle to about 1200 rpms. Then, the high and low pressure readings go into the normal range and it starts blowing cold air. How can I tell if the compressor is bad or maybe the orifice is clogged or the system still has air in it? This is frustrating because I always do everything by the book to avoid problems like this one. Thank you in advance for any help. I appreciate it.

I just put the guages on and it looks like the low pressure side is okay. It's about 65 to 70 degrees amient temperature outside. Here are the readings:
At IDLE
low side = 35 psi
high side = 125 psi

At 1500 rpm
low side = 20 psi
high side = 150 psi

This is really confusing because the needle on both guages are stable and the hose just after the orifice is cold. I flushed out the condensor and the evaporator with an approved can of flush and then forced out the flush fluid with my compressor. Everything is new. Could this be a problem with air in the system? I used an air vacuum venturi pump with my compressor which was overated for the job, to evacuate the system. Could there be an air blockage?

[AzTumbleweed]

I changed my car to R134a and it's never performed very well.

[frafreg]

Originally Posted by AzTumbleweed

I changed my car to R134a and it's never performed very well.

I converted to R134a back in 2005 and it was never as good as R12 but it was good enough. When the compressor seized it was pumping out cold air right to the end. I've been looking all over the internet for answers as to why my high side pressure is low. I'm thinking that there may be a blockage in the high side or the condensor, or maybe the orifice itself. I flushed the condensor and the evaporator with flush fluid and then blew it out with the compressor. I was also thinking that maybe the vernturi pump I used which you hook up to your compressor to evacuate the system, may not have done a good job and there might still be some air in the system. I don't have the money to tear it all down unless I know what to do before hand. I might be rolling down the windows this summer. Thanks.

[AzTumbleweed]

Kind of sounds like a bad compressor. I wonder if you had an orifice that was too big if it could do this? If the hole was too big then it wouldn't build up as much pressure. I guess that's a long shot though.

[frafreg]

Originally Posted by AzTumbleweed

Kind of sounds like a bad compressor. I wonder if you had an orifice that was too big if it could do this? If the hole was too big then it wouldn't build up as much pressure. I guess that's a long shot though.

I remember going to a few different places to match up the hose that has the orifice tube in it until I got the right part. The wrong hose didn't fit on one end. I believe it was on the evaporator side. After all of my research I now think it may be either the compressor a blockage in the orifice tube or air in the line. I'd be surprised if the orifice is blocked already since everything is brand new and I flushed the condensor and evaporator. I suspect the compressor more. I got it from a junk yard and I replaced the three o-ring gaskets to make sure I wouldn't have any leaks. I also replaced the front seal. It looked pretty clean inside but you never know. I think what I might do is evacuate the whole system again but this time I'll use a vacuum pump instead of the venturi pump. I'm not so sure I trust that it pulled an adequate vacuum. Thanks again for your input. I appreciate it.

[frafreg]

I have been going over my receipts and I was wondering if the hose I got from Autozone could have had the wrong orifice tube inside? I see that there are a lot of different versions of orifice tubes. I was thinking that just because it fits, doesn't always mean it is right. Just a long shot. Also, wouldn't a restriction create more pressure, not less pressure?

[frafreg]

Originally Posted by frafreg

I have been going over my receipts and I was wondering if the hose I got from Autozone could have had the wrong orifice tube inside? I see that there are a lot of different versions of orifice tubes. I was thinking that just because it fits, doesn't always mean it is right. Just a long shot. Also, wouldn't a restriction create more pressure, not less pressure?

I did a little more probing tonight. I felt the hose going into the condenser from the compressor and it was very hot. The hose coming out of the condenser was considerably cooler, especially as it got closer to the orifice. After the orifice, it was very cold and condensation was dripping from it. That same hose was not as cold just before it goes into the evaporator. I tried to remove the blower fan but was unsuccessful because there was not enough room to get it out. I wanted to take a peek at the evaporator to see if there was any junk in there. With the car at idle, I checked the low pressure which was at 35 psi and the high pressure was at 125 psi. I blocked the condenser completely and the high pressure went up to about 150 psi. After I removed the cardboard from the front of the condenser, I watched the needles on the gauges and they returned to the same pressure slowly. I also made sure all of the heat controls were working properly. The heat temperature control, the vent for inside or outside air, and the control that diverts the air from the top vents, to the floor, to the windshield were all functioning properly. I guess I'm back to square one again. Any thoughts? Guess I’m back to evacuating the system.