auto a/c problem

Hello, friends. I am a long time scannerdanner youtube watcher, automotive tech student, and new to this forum.
I have a 2001 nissan sentra gxe 1.8 that has all new a/c components but is NOT cooling. on the highway it gets down to 62 at the center vent. when I stop it goes up to 80 very quickly. I have replaced the a/c compressor, txv, condenser, accumulator / drier and evaporator, but all at different times because I couldnt afford to do it all at once.
--It does not leak refrigerant.
--I vacuumed the system for a full hour prior to charging.
--it has enough oil in the system.
--Condenser / cooling fans work properly.
--I DO see it dripping water from the evaporator drain under the car when it is running.
--I have installed a water shutoff valve to my heater core.
--I properly charged the system with my scale and drum to 1.1 lbs (I am able to buy the 30lb drums because I have a 609 license)
--Recently my compressor took a dump so I replaced it and the condenser, but NOT the accumulator / drier because i replaced it 6 months ago (Lack of money).
--The low side gauge goes down to 25-30 at 1500 RPM, which is good.
--The high side gauge stays around 150 at 1500 with a proper charge, which is low.
--If I over charge it a little I can get the high side to go up to 250 at 1500 RPM which is good but not good at the same time because it is over charged.
The accumulator / drier is tricky to install because of its position in the car so it was absorbing atmosphere for about 45 minutes until I could get it all put together. Because I removed and reinstalled / reused it, that means it has been exposed, completely open to atmosphere, for around an hour and a half total. (It was under 28 inches of vacuum for an hour both times before charging)
I do have a certification in this field but lack the experience to diagnose it quickly and efficiently the first time. It takes me a while to figure it out.
Can someone please point me in the right direction? Im starting to melt when I drive in this south Texas heat.....

As I'm sure you know, the "cold" happens due to the pressure drop from the High side to the Low side. Your low-side pressures look good, your High-side pressure may be a little on the low side, but I think the pressure difference should be plenty to "make some cold". Ambient temperatures can effect the high-side pressure, too. Is it a cool day? The High-side, before the TXV, should feel pretty warm...almost hot. After the TXV and Evaporator, the Low-side line should be very cold. Do you have an IR thermometer to read the temp difference? Is the low side line a lot colder than the air coming out of the vent?

chads370z wrote: Im starting to melt when I drive in this south Texas heat.....

Oh, I guess, it's not a cool day. :woohoo: I WOULD expect to see higher pressures than that. Due to the "not high" pressure, I think, you can rule out your condenser and fan.

I have one to look at one next week with similar issues I did a quick check on the pressures which were fine, but the temperature difference between the pipes on the high and low sides isn't great so I suspect either an expansion valve issue or excess oil in the system with the oil filling most of the condenser.

yes, it blows colder at night when it is cool outside but it STILL never gets below 60 and yes, the low side line seems colder than the air at the center vent. I do not have an IR thermometer yet. I might get one from harbor freight just to check it.

I did notice that the low side line under the hood gets pretty cold and drips condensation but the high side line only gets warm, not hot like my college instructors told me it should be. im starting to think maybe it is the TXV, even though it is only a few months old. I bought it from o'reillys and we all know how unpredictable their parts can be

I wonder if you could t could be an issue with the air blrnd/distribution unit ?

Andy.MacFadyen wrote: I wonder if you could t could be an issue with the air blrnd/distribution unit ?

+1

I would, definitely, check into this, before replacing the TXV.

I can see the blend door opening and closing when I move the temperature selector but that doesn't mean its still sealing after 18 years. I can reach up under the dash and feel that it is all the way closed in the cold position. I REALLY dont wanna have to pull the dash on this 01 sentra because I am in school, have never done a job that big and it would probably take me a few days to get it done with a lack of experience. I am watching videos on youtube to see if there is a short cut, like remove the radio and a/c control head and access it through the open hole, etc. I will let you guys know what I come up with.

chads370z wrote: I do not have an IR thermometer yet. I might get one from harbor freight just to check it.

I keep one of their Ames thermometers on hand for brake inspections, and seems to produce consistent results.

Definitely seems like a TXV issue to me, given the ambient temperature and pressure readings. Might be time for a dealer part, if they exist.