a/c pressures are bad- possible restriction after retrofit

[clydesdale]

I retofitted my system to 134a. I flushed the condensor and drained the compressor of the mineral oil. I refilled with ester oil, replaced the drier and pulled a vacuum. I then filled with refrigerant and have only added about 20 ounces at this point. The sytem calls for about 30 ounces and here are the pressures that I am currently getting. This is from a post I made on a different forum:

ok, here is what I have going on now:

This morning the pressures seemed a lot better. The low side was about 20 at idle and high was 150 with a/c on. I added about 1/4 can of gas into the low side. The pressures seemed to get to the upper limits of 35-40 low side and about 225 high side. I then drove the car around for 15 minutes, came back and reconnected the gauges. The gauges now read low again at 30 on the low and 200 on the high. We then put another 1/4 can in, which would mean there is now 2 cans of the 2 1/2 that should go in. The low pressure is now 40-45 and high at almost 300. When I then went for a drive the duct temp would only get to about 62 degrees and it is 78 degrees outside. After driving for another 15 minutes, I came back and put the gauges back on. The gauges then read 40 for low side and 175 for high side at idle. When I bring the rpm up to about 2000, the high side approaches 300. I then shut everything off and the low side goes up to about 100 and the high goes down to about 150. Any thoughts? I still have bubbles in the receiver dryer site glass and am still under the amount of refrigerant that I should have added. I am confused. Sounds like a restriction, but why and where?

[jlevie]

What you are seeing could be a bad expansion valve, or (depending on the ambient temperatures) it could be the result of R134 in a system that is sized for R12. Specifically, the condenser on an R12 system is way to small for R134 and will cause higher high side pressures. The higher the ambient temperature, the greater the high side pressure.

[reelop19]

Nail on head there dude. I'm having the same issue if its over 90 degrees F outside. Under that a/c blows so nice and cold and yes my compressor pressure is a little high

[clydesdale]

Here is an update, since I completely reflushed the car and put in the proper amount of oil and refrigerant. My high side pressure can get as high as 350. I have retrofitted to r134a. I have 29 ounces of r134a in there and 10 ounces of ester oil. I completely flushed the entire system and put in a new dryer and expansion valve.

I currently have the evaporator box cover loosely in place. This is the cover that goes over the expansion valve. So, the box is not sealed. I did this so that I could easily look for a leak. The problem is that my duct temp is still only about 63 degrees with the outside temp 80 degrees. But, the evaporator is dripping water and the low side pipe is damn cold and has condensation all over it.
When I spray down the condensor with cold water, I get a good 50-75 high side pressure drop and then the duct temp drops about 5 degrees.

How can I tell if my auxillary fan is spinning properly. Is it one speed or 2 speed? Any other thoughts? Thanks.