93 tuneport FI starting problems

hey my friend has a 93 tuneport FI motor in a 86 iroc and it was running ruff and now the motor wont start and back fires in the intake.
he played w the distribitor and setting the motor on TDC and still nothing.
help pls!

1993 350 is an Lt1, very different from the TPI.
Did he try to pull the codes from the ECM?
Where did he get the ECM and harness from? Hope it wasn't a corvette