Some good points Mr.Bill..This is 1995,sensor wire does run to molex plug at board,has one harness plug inline,,i checked both. I did run a jumper wire from burner/sensor ground to board ground.
Isolate the flame sensor out of the equation. If you have above 45 volts to, I want 96 volts (Flame Sensor Sending Wire To Meter To Ground). Next just grab an 8 penny nail, hooked to sending wire and hold like a surgeon with needle-nose pliers and keep in flame and see if you get Amber light. If you have seen amber even for just a second then there "WAS" a path. Now its back to basics, Ground or board line output.
The flame might not carry over everytime to the sensor. Clean or widen burner slot slightly.
Got it! But ugly.. Went back with new board and installed. Same thing inducer starts.HSI glows,burners lite,runs for 3 sec. flame goes out. Flame lite on board does not lites! Home owners looking over my shoulder whole time,more questions than a two year old! Figure its got to be wire from board to F.Sensor. make up jumper from Molex plug straight to F.S. grd screw. Nothing! Time to check main power supply in furnace cabinet. Open up, take voltage 115V. Decide to jumper neutral and ground wire "SPLASH" W.T.F.!! Now I start interogating home owner.,He had done some "clean up" work in his Main power box this summer.,he had not been using furnace yet this year cause he was out of Propane.,he never thought that could be the problem,cause A/C worked fine all summer! I made up extension cord to another elec. circuit.,thing worked fine! Home owner says smiling.,well atleast I dont need that exspensive board ! And I said you might as well keep it...,your paying for it! Consider it an "Electricians charge"! Thanks all for the help!