PD 6428 then QF 3748 at San Francisco
Chicago O'Hare → San Francisco → San Diego
Timetable, San Francisco time
16:19PD 6428 from Chicago O'Hare at the gate
08:20QF 3748 to San Diego leaves the gate
16 h 01 apart on the timetable, overnight
QF 3748 leaves 16 h 01 after PD 6428 arrives on the timetable: more than half a day, so not a connection we count.