sounds normal, the only thing replaced was the ignitor?
have your double checked all the other wires to make sure they were not accidentally moved or disconnected?
you can try to connect the red (R) and the white (W) at the back of the thermostat and see if the furnace starts.
is this a battery operated stat?
try to remove the batteries for at least 6 min. than reinstall, this will rest the stat.
the first thing to stat will be the inducer fan motor than after apox 45 sec. the ignitor should start to glow.
this does not make sense.
you can try to go to the furnace, remove the lower door, than try connecting the R and the W , where the stat wires connect, than hold the door safety switch in and see if it starts any thing.