80s or 90s RHEEM Imperial Plus 90 furnace Ignites- quick flame over and over clicking and wont start

[Borninabarn]

Hello All Any HVAC Pros out there
I have a 1980s or 1990s RHEEM IMPERIAL 90 PLUS Furnace that wont start up? A few months ago I replaced the small enclosed fan and put a new plastic hose that goes from that to the steel round diaphragm unit? And that fixed the furnace 6 months ago but it quit running the other night and just that small fan unit was the only thing running no flame,no ignite? I took the single igniter out the one with the spark plug wire on it and cleaned that up again with steel wool and some light sandpaper.I blew everything off, put a new filter in it,made sure that sensor was reset(red plastic dot on top)checked all the wires and now the only thing the furnace does is IGNITES QUICK FLAME,NOTHING IGNITES QUICK FLAME,NOTHING all in under 30-45 seconds and then nothing other than that small fan keeps running?? Its still getting Cold here in Iowa 50s during the day and 30s at night so we do need that furnace to work. Hope someone can help Thank You,Born

RHEEM IMPERIAL 90 PLUS
Model# RGEA-07EC-FS
SS# BN3D202-F3687 5496

 

[Borninabarn]

UPDATE! I jumped the red wire to the white wire on the furnace thermostat board turn the power on and the furnace powered up ignitor zapped and started the flames and then it shut down(The blower never came on? I disconnected the jumper I had on from the red to the white I replaced the cheap $18.99 digital thermostat we bought 6 months ago and put a better upgraded Honeywell digital thermostat on.I threw on the power switch again and the furnace induction fan started then the igniter zapped started the flames on the burners the limit switch moved slowly up to the point where the main furnace squirrel cage should start to blow the Hot air and the flames went out and the only thing running is the induction fan again? That little thermo switch with the red button is still down.Any ideas on why the main blower fan doesnt start and keep running along with the burners?? Anyone know whats going on that knows about furnaces?