What was found
D: PHX - AIR TURNBACK - AFTER TAKEOFF NOTICED AIRCRAFT YAWING AND #1 ENGINE SURGING; STOPPED CLIMB AND #1 ENGINE CONTINUED TO SURGE; CREW FOLLOWED QRH AND INITIATED THEIR RETURN TO PHX; ABOUT 10 MIN. LATER THE PMC (POWER MANAGEMENT COMPUTER) INOP LIGHT ILLUMINATED; THE CREW TURNED THE PMC OFF AND NO FURTHER SURGING WAS NOTICEDC: MAINTENANCE TROUBLESHOT AND INSPECTED THE ENGINE INCLUDING THE PMC; FOUND CONNECTORS ON THE PMC LESS THAN HAND TIGHT; AFTER TIGHTENING THE CONNECTORS THE ENGINE AND PMC FUNCTIONALLY CHECKED GOOD; THE ENGINE HAD JUST BEEN INSTALLED ONE FLIGHT PREVIOUS TO THIS EVENT