Abstract: An air compressor assembly is provided having a high pressure air receiver, a compressor, an outlet port and an inlet port on said compressor, said inlet port having a normally closed spring loaded inlet valve, the improvement comprising a two position normally open spring loaded poppet valve on said compressor, oil pressure actuator means acting on said poppet valve opposite said spring, receiving pressure oil from a pressure lubricating system in said compressor to close said poppet valve against the spring in normal operation of the compressor, a pulsation damper having upper and lower chambers connected by a metering means between the compressor and air receiver, a connection from the compressor to the lower chamber delivering high pressure air thereto, a connection from the lower chamber to the air receiver, a connection from the upper chamber to the poppet valve on the same side as the spring, a pressure responsive actuator means selectively acting on the inlet valve, and a connection from the poppet va