I have a similiar furnace, the XR80. On mine, the first thing to come
on is the inducer fan by the exhaust, then the igniter, then the gas
valve opens to ligght the flame, then the blower.
By the inducer motor I think there is some kind of safety switch, it's
a tube to detect air pressure which senses that the inducer fan is on,
otherwise it will shut down. Check if thats clogged or stuck.
You say your ignitor was replaced already. To be sure put a meter at
the leads and see if it's getting 110V after a few seconds when
calling for heat. If it is, then you have a bad ignitor, otherwise,
something in the circuitry is telling the ignitor don't come on
because of a problem ( for example, maybe because of the inducer