Car Cranks Won’t Start after (during) O2 repair

[pk2]

1) A couple days ago parked 99 Box to replace pre-cat O2 sensors (for snog, running fine)

2) With O2’s out I fired it up briefly to hear it loud

3) Car sputtered out after a few secs., not surprising with no O2 (I thought)

4) Installed new O2’s

5) Cranks but won’t start, smell plenty of fuel out the tail pipe, obviously no spark at all

6) No obvious flame damage to anything above O2 sensor ports (flame damage)

It basically quit not to be started again when I ran it briefly ran with nothing in the O2 holes…coincidence? Ideas any one?

Regards, PK