System will not take a full charge

[nitropete]

I’m repairing the a/c system on a 2009 F-150. System will accept 10 ounces of r134a and then dead stop, not take another ounce. New compressor, condenser/drier, evaporator including expansion valve . I’m a fleet tech and usually pretty good at sorting these types of issues. But this ones got me stumped. Checked that all lines are open and clean . Powering the compressor clutch, engages but makes no difference, checked pressure switch. Is it possible the new oem expansion valve could be the issue , possibly closed and not letting system fully charge. Also, low side responds slip during vac down

[Tim]

Is the high side open on your gauges? For starters, make sure it is closed. What's the temp you're trying to change the system in? This time of year can make it harder to charge in the cold.

[JohnHere]

Does the cylinder from which you're charging contain any refrigerant? It can weigh quite a bit yet still be empty. Sometimes, we tend to overlook the obvious.