Can't get full A/C charge

[RatLabGuy]

'93 toy-Yota pickup.

Originally had R-12, few summers ago it finally let out. I tried Freeze 12, replaced receiver/dryer, that slowly leaked out too. Alas. Put some dye and R134a to chase it, found some around the compressor O-ring. Pulled it, drained it, replaced ring.

It holds vacuum fine. Was only abou tto get ~14 oz of 134a in, and even that was a fight... when I gave up, it was reading ~55 on the low side, almost 250 high side. So good pressure, but not anywhere near the spec of 29 oz.

Not surprisngly its not very cold. ~10 degr vent drop.

Any idea what would cause this? Maybe still some old oil / something stuck in TXV? Its just weird to me that the pressures got to be normal w/out putting nearly enough refrigerant in.

 

[skyhighZJ]

Something is taking up space that the refrigerant should be occupying. Oil, dye, trash in the system. Are you charging it while running, A/C on full blast? How are you charging it? Tank on a scale with gauges? Machine?

 

[Jeff B]

condenser or not enough air flow. May need to check the evap coil, needs air too.

 

[RatLabGuy]

Something is taking up space that the refrigerant should be occupying. Oil, dye, trash in the system.

This is my thinking as well.

Are you charging it while running, A/C on full blast? How are you charging it? Tank on a scale with gauges? Machine?

yes.Using the classic manifold guage set, 12 oz can on the yellow line. Can set on a small scale so I can measure mass drop.
Shake/ spin can and do a little interperetive dance to help get the flow out. No fancy machines here.

I'll probably bite the pullet and pull the TXV, replace it and flush that end of the system.

condenser or not enough air flow. May need to check the evap coil, needs air too.

It doesn't seem too bad, but I'll clean it w/ some condenser cleaner for good measure. Sicne this sort of happened all at once I'm less likely to think its just grime buildup