1997 Pontiac Sunbird starter problems

Electrical problem
1997 Pontiac Sunbird 6 cyl Front Wheel Drive 177129 miles

My son replaced the starter in his sunfire. The cause was a worn bendix. Prior to that he made an attempt to start it and it did start. After replacing the starter the engine now cranks but will not fire. The small post of the solenoid has a red wire attached but there is a black wire that looks like it has to go there but when he removed them he forgot the exact location. I'm wondering if that may be the problem or do we need to look in another area