Suburban SW6P no spark

[trackhead]

1993 6 gallon Suburban SW6P in our truck camper.

Worked fine when we bought the camper, then would light, burn for 5 seconds or so, then shut off. Able to get it to work again by blowing out burner tube (probably coincidental). Worked for five trips, now won't spark. If I turn it on, I can light it with a lighter, but again, it burns for 3 seconds, then shuts off.

-No visible spark when observed in the dark.
-Reset fuse on high temp switch not activated.
-Oven, furnace, refridgerator work fine.
-12.7v at battery.
-I tried to bypass hi-low thermostat, but no change (might not have done correctly.
-Current 12.7v when checking input-output wires from thermostat, when thermostat removed.
-I can here gas solenoid opening/closing, also can light manually.
-Tried to clean temp sensing rod/igniter without success.
-Significant corrosion at mounting point for igniter (bad ground?).

I ordered new board and hi-lo thermostat, waiting for items to arrive.

Any insight?

I'm guessing the temp sensing/flame sensing function is gone. Or could it be a thermostat shut off issue?

[Dr_Quick]

I had trouble with my water heater a few years ago. One of the "spade connectors" was dirty. Cleaned it up and it has worked fine since. You might try taking all these connectors apart and cleaning them, then put dielectric grease on them.

[trackhead]

Fixed it with a Dinosaur board........

[old_guy]

last year in Yuma mine would not light, no sound or any thing. got home and my friend the service man came over and took the black reset cover off and wiggled the wire on the reset and it took right off.

[trackhead]

Waiting for parts, in the meantime.

-Grounded flame sensor with extra wire to clean ground, no change.
-Checked voltage through both thermostats. 12.7v going through both, and 12.7 at board.
-Cleaned ingitor, no change.
-Still lights manually then shuts off.

So somewhere from the board to the ignitor seems to be the problem. Maybe the new board tomorrow will fix it.

[ScottG]

I have fixed several things like this just by cleaning the flame sensor or thermocouple. Use a BRASS brush to gently remove carbon or, carburetor cleaner does a great job of melting carbon too.

[sclark]

My guess is the flame sensor has failed or needs cleaning. Same with the spark ignition. Good luck.

[trackhead]

Thanks, I guess it's no different than a spark plug gap on an auto.

[TucsonJim]

Your igniter may have moved and the gap is too large to spark across. Try moving it closer to the spark point and try again.