Gas Stove Igniter CONTINUOUS sparking even after ignition

[CMacRun]

This must be the most elusive issue with gas stoves. I've scoured the internet and have only found the most obvious culprits and solutions. 

I have a Thermador Cooktop GPS484GGS. 4 burners, 1 grill and 1 griddle. 2 burners have solenoids and 2 do not. The ones with the solenoids work fine (the Left front and back) the other two (Right front and back) will light up just fine but the the sparking continues even after lighting. However, if both burners are on at the same time the sparking stops. Keep in mind I've replaced all igniters and even moved them around. They are not dirty, wet, nor are the wires or switches. All works fine with the exception of the continuous sparking. I'm looking at replacing the spark module but understand that is rarely the issue - especially if there was no sparking problems before the repair.

 

FYI the whole reason I did the repair was that 1 igniter lost its c-clip (holds the igniter in place). If the igniter was not standing upright it would allow too much gas in and by the time it sparked there would be a small explosion. This was a big job requiring me to drill out the Venturi tubes, replace the burner base, nuts... a major pain... Now I have an issue that did not exist before. Thanks for reading and any help anyone can provide.

[AccApp]

Check all paths to ground for the ignition spark. You want as little resistance as possible. Check especially all mating surfaces of the burner heads as they are prone to corrode and form a high resistance in the path to ground.

[Econo Appliance]

If the sparking stops with two burners on,  then sounds like you've got mixed up wires.  Triple check again.  Light one of the problem burners,  then take your torch and apply flame to igniter of the other problem burner.   If sparking stops, then you've got wires crossed up.

[CMacRun]

5 hours ago, AccApp said:

Check especially all mating surfaces of the burner heads as they are prone to corrode and form a high resistance in the path to ground.

So that would mean: burner head to base and base to spill tray and electrode to spill tray...?

I tried switching the wires (front to back / back to front) but no changes.

Parts that are new are: burner bases, electrode and Venturi tubes.

Burner heads are not new. Guess I'll try a little sanding / filing.

[Rhubarb Tau]

If the RF keeps sparking unless the RR is lit, and the RR keeps sparking unless the RF is lit, it sounds mis-wired to me too. I  like @Econo Appliance's trick of using a torch to satisfy the sensor.

Just to be clear, when you swapped the electrode wiring, you left the wires connected to the spark module in the same positions, and just reversed which burner electrode they wired to, correct?

 

[johntech]

You could always swap the both left and both right ignitor wires at the spark module and see if the problem moves sides. Normally this is caused by corrosion, improperly assembled burner heads or dirty burners like everyone else said. If the flame is not even all around the burner that could cause it to keep sparking. 

[CMacRun]

2 hours ago, Rhubarb Tau said:

Just to be clear, when you swapped the electrode wiring, you left the wires connected to the spark module in the same positions, and just reversed which burner electrode they wired to, correct?

Yes. I've not touched the module. I like @Econo Appliance suggestion too but won't have access to the unit again until next Tuesday. Will also try the @johntech  suggestion to make the swap at the module to test sides. The L side is the one with the solenoids so it functions very differently - one spark, ignite, done  - so that should be interesting. ----- Thanks to all of you for the very thoughtful suggestions. 

[CMacRun]

Ok, tired @Econo Appliance suggestion using the torch and it worked - the torch on the opposite burner stopped the sparking. However, even though I know the wiring is the same as before the repair (marked wires), I swiped the Back and Front burner ignition wires and the problem is the same. Would anyone recommend changing the ignition module at this point? It's just hard to believe the module needs replacing since there was no ignition issue before the repair. Thanks for any insights.

[CMacRun]

that's tried not tired - sorry about that.