Refrigerator Not Cooling

My Dometic 8501 fridge wasn't cooling well on my last trip. Seemed like the flame was minimal (about 1/4-1/2" high) and I couldn't hear it inside the trailer like I normally can. Inadequate gas flow seemed like the obvious answer so I pulled the gas line in the back of the fridge and cleaned the orifice as well as the burner. Both of them looked clean but I did it anyway. I then pulled the top off the flue and blasted it with my air compressor. No soot or debris came out the bottom. Next I disconnected the gas line from the gas valve, disconnected the main gas line downstream of the regulator and blew that out. Again, no gunk or debris. While I was at it I blew out the back of the refrigerator and cleaned the fins with a damp cloth. Thinking I'd covered all the bases I put it all back together and tried to fire it up. Now the igniter sparks like crazy but it won't ignite. Probably should mention that I removed the gas valve just to take a look at it and because I couldn't help myself. I also lit a match and placed it over the burner while it was trying to ignite just to see if maybe the igniter had moved out of position. No luck there.

Double check that the 12v wiring is connected and that the connections are tight.  You have 2 / 12v leads going to the burner (an igniter and a thermocouple)  Also make sure you have 12v power to the fridge.  While running on gas you need 12v power for the controlling of the gas operation, if that makes any sense.  If the igniter is working then you have 12v power.  It sounds like you have bleed the LP line by using the stove but that might still be the problem.  Just try lighting the fridge a couple of more times.  Hope this helps.

Yep, I have 12v power. I just re-checked everything and noticed that the green ceramic piece on the positive side of the gas controller has fallen apart. It's still igniting well, but I'm afraid I may not be getting gas through the controller. 

I took it off because that looked like the easiest way to get to the short line that runs from the control valve to the main copper line. I didn't take it apart. I wanted to make sure I was able to blow out all the lines. I made a note of what wires went where, plus they're marked positive and negative on the control valve. The little green ceramic piece that the wires connect to has disintegrated on the positive side and I think that is the source of it not getting gas. It's either grounded out on the body of the control valve or not making a good connection? Per Stephen H's comment, I let that igniter run through about 20 cycles, but no go.

Right. The gap is good.