On my 2002 F-150 SuperCrew, 4.6 V-8, 2WD, I replaced the compressor, accumulator and orifice tube, flushed and vacuumed. Weighed and filled 33oz per OEM sticker on radiator bulkhead. Low pressure is 78psi, high pressure is 430psi at 85°F idling. Above idle, high hits 475 psi and the high pressure switch opens the clutch until it drops again. While filling the first and second 12oz cans, the line just after the orifice tube was nice and frosty but with more fill it got warm. Any ideas why pressure is so high at factory spec 33oz fill?

 

Orifice tube installed properly?

You prob have a junk fan clutch. Run a garden hose on the condenser and a good sized fan. See if head pressure drops.

 

The pressures are lower when it's cold. When warmed up I hit the condenser with a spray mist and the low side went from 71psi to 67psi, high side from 450psi to 415psi.
I ended up taking out about 10.5oz of refrigerant. Now it about 35psi on low side and 235psi on high side, interior temp is 65° in the shade. I tried to measure the orifice tube to evap line with an IR thermometer but can't get a good reading, need a thermocouple... The line is cool but not frosty like when I was putting in the first two 12oz cans.
I thought I put the orifice tube in correctly but may need to check it. Any recommendation on checking the fan clutch? I don't have an optical tach.

 

Your vent temps are also junk w pressures that high. Pressure increases with temperature and vice versa. Physics 101.

Pretty sure these trucks use a blue FOT, usually have small arrow to point proper direction into evap. At least that is what came out of my Expedition and Screw. You are also now about 33% low on gas.

Leave AC off for now. Start truck and let idle for say 15min. Hood open and turn it off or have a helper. How fast does the fan stop? Or does it just spin about in a lazy manner? Or hell, spin it by hand with engine off. If easy, clutch is junk. I bought a Motorcraft for $80 but a Hayden works well too.

Do you have one of those OBD2 deals to check running data? I got one from a pal and use TorquePro I think. Works great to check basics. Curious of operational temp at idle.

 

You have a blockage in my opinion
It should be shooting the freon thru the evaporator (thru the fixed orifice) fast enough as to not build excessive head pressure like yours is
The cooling of the condenser is critical too
Better pull the freon back out and check the orifice that just plugged up again

 

I checked orifice tube, it was correct. The pressures seem a little better now, 45psi low, 270psi high, idling at 90°. But they're just at the limit of the specs and that's with 24oz refrigerant instead of 33oz. Still seems like something is not right.
The fan does not spin freely by hand, there is some viscous resistance.
I don't have an OBD comm tool.

 

Seems like something is blocked. I had pulled out the orifice tube to confirm it was oriented correctly, it was correct and not clogged. Would a blockage also cause excess pressure on the low side? The restriction has to be downstream from the pressure port (couldn't be the muffler). Could the condenser have a blockage?

 

Where are you located? I have a yuge shop fan and squirrel fan for blasting air through front.

I once fixed a Toyota truck with a fan installed in reverse.

How long have you owned this truck? Ever done a fan clutch? Any trash between cond and rad?

 

Aim the fan ESE and turn it on high, I'm on the Florida Gulf coast, ha, ha. I replaced the rad late last year due to a major leak, no nests or other debris then. I'll have to check now.

I've had the truck about 5 years. The A/C never worked great. When I now replaced the accumulator, orifice tube and compressor, there was evidence of wear/damage (metal flakes on the orifice tube).

I haven't replaced the fan clutch. I could ask the guy I bought it from.

 

I had the fans on, did they help?

 

Poor cooling with excessive high side pressure sure sounds like a problem cooling the condenser which could definitely be a bad fan clutch.

 

In Texas I tend to receive 8-10 years tops from a clutch. Obviously some built better than others, but seems normal.