I have a 94 Camaro Z28 and I recently replaced the a/c compressor on it. After pulling vacuum, then adding freon the system keeps shutting down like it has low pressure. However, when I put my manifold gauges on the pressures show to be fine with the system running and on max cool.

It will sit and idle all day long with no issue. The only time the A/C finally quits is when the car is driven for a few minutes. Then the compressor stops.

So what would cause it to work fine and show fine at idle but make it stop working once the car is driven?

Thanks!

 

Check the high and low pressure readings while car is at around 3000 rpm with AC on max. Record those readings and get back with us.

 

since the pcm controls the ac, you really need to put it on a scanner and see what the evap temp is and what the high side is reading thru the pcm, most generic scan tools only show the ac presure and not the evap temps on live data, gm tech 1 and 2's show this and data master does. if you dont have access to any of these I would do as the last post says, did you weigh what you put in? it should have been 2lb, or 2 1/2 cans if you were using 12oz cans