Payne Furnace pilot won't ignite properly

[zeal]

I have a Payne Furnace, model 394GAW036050 that won't light automatically. Gas furnace. The first issue was that the electrode sparker would spark continuously for many minutes until the pilot flame would ignite. I switched out the pilot burner and now have a new problem. When the thermostat calls for heat, the furnace does nothing. The sparker does not spark. If a light it by hand the pilot will light and the sparker will start sparking like crazy. Once I light the furnace by hand it operates perfectly. Why won't the sparker start sparking itself when asked to? Why is gas flowing without the sparker sparking? Also, this is intermittent, sometimes it will light itself and sometimes it won't. Please help.

[how]

How old is this furnace?

Everything points towards a faulty ignition board. Make sure that all grounds to the board, furnace elect box, pilot and right back to your electrical panel for your designated circuit are very tightly connected as loose grounds can cause erratic board behaviour. Do you have a led light on your board that is flashing a diagnostic code?

[zeal]

I would say the furnace is 25 years old. It doesn't have any LED's unfortunately. I cleaned all connections, they are the slip fit kind. It's upsetting because the sparker was working like a champ before I replaced the pilot burner. After the replacement, the sparker wouldn't work until the pilot was light by hand. Strange. Maybe I did knock some connection lose during the replacement. I will check them again.

[how]

Boards can be damaged by loose grounds. Pay close attention to the greens lines and the way they are secured to the furnace and components. Even replacement boards will behave erratically if a problem ground line is not fixed.
Does your furnace have a separate board for the igniter in addition to the motherboard?