1990 Oldsmobile Cutlass Engine not running.

Engine Mechanical problem
1990 Oldsmobile Cutlass 6 cyl Front Wheel Drive Automatic

A short story first. Stop the car (forward), put in reverse, back up into a 2 point turn, stop, put in drive. Engine stops with a "CLUNK". Every time key is turned to start position, single "CLUNK" and the block jumps. Thought may be the starter, it's new, checked oil for metal shavings, nothing. It's not my car and not near me, more like 3000mls from me. It's my nephews car and he doesn't know the first thing about cars. I'm trying to help him. I have my own thoughts of what is wrong but wanted another opion. Thx all who reply.