Furnace, model no. gdpi075-3, I am getting spark to the pilot, pilot lights, spark continues, but valve does not open for main burner. This is a dual stage gas valve. There is 24 volts at pin 4 on the gas valve, I also measure 0.76 volts at spark control, this wire comes from flame sensor. With all wires removed from gas valve on ohms I measure 8.9k from pin 4to 2, and from 2 to 3 I measure 109 ohms. #pin 2 and 1 have a jumper.

Sand the flame sensor and try again.

I forgot to say I installed a new circiut board (other was burnt) and replaced flame sensor. I am more concerned about the resistance measurement. Does 8,900 ohms across the pins sound to high? And if there is 24 volts there for the first stage to light the pilot what signal or voltage tells the second stage to come on. Also is there a schematic that would show the voltages in progress