A/C pressures for R134 system?

[98EdBomber]

I have a 98 Explorer that wasnt blowing cold air, so I checked the pressures with a proper gauge and in fact was too low so I slowly added R134 until I got the pressures up and the air started to get cold.

I drove about an hour today and the temp outside was 105F+ and I noticed the air wasnt as cold as I thought it should be so I get home and check the pressures again.

Low side static and high side static were around 100psi or so.

Low side running full MAX AC was hovering around 31psi with compressor running.

High side in the middle between 200-250psi so im assuming 225psi or so.

Does anyone have a proper chart that shows the correct psi pressures and temperature ratings? Ive added about 1 and a half cans of the small r134 cans to the system and think it may need more. Low side 31psi in 105F+ temps seems too low to me.

I know the proper way would be to evac and refill to spec but im wondering if it is still undercharged?

I dont have a vent temp gauge so im not sure what the temps are but they dont seem like they are in the 40's even when I test it in the garage, out of the hot sun. Which would still be around 100F Im assuming.

 

[fixt]

It might be a little low.
Static at 105 F shows 135 psig for R134a.

There's a million charts out there. In case this one can't be read, just plug in R134a pressure temperature chart to your search engine and just pick one.

 

[98EdBomber]

Perfect. Just what I was looking for. My hood tag says it holds 1lb 14 oz. I only put in 1 small 12 oz can and then about 75% of the other can. Before I started to fill I dont think there was much in there at all because the compressor cycled on and off and when I jumped the (forgot the name) switch to run the compressor constantly, I was getting damn near zero on the gauges. Which means I prob have a leak. I added dye but havent seen anything yet, so I will see how long this holds up. I was thinking I could add the rest of the can and be OK. Im getting a thermometer for the vents today to see what Im actually getting. Thanks!

Also if I wanted to get it very accurate, where should I be measuring the ambient temps from? In front of the condenser?

 

[fixt]

Yah, about 3" in front of the condenser. Windows down, max ac, about 1100 rpm. I've never had to jumper the low pressure switch for a constant run, just added to low side until pressure came up the compressor began to cycle. Then start measuring temperatures and monitoring pressures, observing that the drier/accumulator becomes colder while adding. Setting the R134a can in a pan of water while adding will increase the rate of fill.
Sometimes the low or high pressure valve will weep and you can kinda "pop" the valve to seat it, a quick depress and release kinda thing. If that is happening, of course you run the risk of making it worse. The valves can be replaced without depressurizing the system.
The valve caps are also a pressure boundary, so you want to make sure those are in good shape.

Sounds like a pretty slow leak. Good luck with it