Cooktop woes, who here knows about them?

[wdfifteen]

I have a Bosch gas cooktop that is working great except for the right front burner. When you turn it on it sparks once, then stops whether the burner is lit or not. All the other burners will keep sparking until the gas ignites. I can't find any help on the interwebs for this particular problem.
I assume there is some kind of sensor in the burner somewhere that senses the flame and it isn't working?

[DonDavis]

Hmmm, when you turn on a functioning burner, is the clicking/igniting all automatic?

The ones I generally see function as follows...
Turn knob to the clicking part, it begins clicking over and over, once gas ignites, turn knob further on and clicking stops.

My first thought is flaky knob contacts. Prob more complex than I'm thinking, but I'd compare a functioning knob with the errant one.

[DonDavis]

Is the right front the most used burner?

[billybek]

Mine operates the same way Don described.
There is a light position and then adjust the burner after it is lit.

If it is automatic, I would look to see if there is some food residue or cleaning product in the ignitor itself or the burner assembly around the ignitor.

[legion]

It could be even simpler, you could just need a new igniter on that burner.

[ossiblue]

Two possibilities, IMO. First, as mentioned, a faulty igniter. Second, the module which controls all the igniters may have a fault. Not familiar with Bosch, but some manufacturers have a single module for all igniters whereas others have a separate module for each burner.

If you can find the location of the module, try switching the connector for the defective igniter with another that works properly. If the problem moves to the formerly working burner, then the issue is with the module.

[wdfifteen]

Hmmm. You've given me something to think about.
I usually just turn a knob on to any level, the sparking starts on all burners and when the one I've turned on lights, they all stop.
I just tried turning the knob slowly, letting the sparking start, and then turn the knob far enough to start the gas flow - it works every time. I'm not sure why this one burner is now operating differently than it used to (and how the other burners still operate) but as described by some of you here, it is operating normally.

[look 171]

Do you see spark? If so, the board maybe bad

[Bill Douglas]

Where the spark jumps to may be corroded or dirty and not getting a good enough earth/ground. Cleaning this will be an easy fix if it works - worth a try.

[Cajundaddy]

If it is only one burner, the igniter is probably gunked up or damaged. Clean thoroughly and retest.

[DonDavis]

Originally Posted by wdfifteen

I usually just turn a knob on to any level, the sparking starts on all burners and when the one I've turned on lights, they all stop.

Guys, this explains the normal operation clearly.
The range doesn't care where the requested gas level is, it just begins sparking then stops on its own once lit.

Since it sounds like its all controlled digitally, could be a faulty board as previously mentioned.

Patrick, is this burner the most often used one? If so, think mechanical first. Maybe there's something preventing a sensor from detecting the flame. But I'd start with some cleaning/inspecting compared to the other burners.

[john70t]

Originally Posted by legion

It could be even simpler, you could just need a new igniter on that burner.

^This

Or the spark path to ground is rusted/coated.

Rotate the hardware. Some of the gas transfer ports (pilot->ring) can get blocked up with gunk over time.

[wdfifteen]

Thanks for all the input. It is strange that it will spark repeatedly for at least 10 seconds if I only turn the knob slightly, after that I can turn the knob far enough for the gas to flow and it keeps sparking until the gas ignites. If I rapidly turn it past that “spark but no gas” setting it sparks once and stops. As I mentioned, that’s not the way the others work. I suspect something is wrong with the switch under the knob. I’m going to watch it to see if it gets worse.

[HardDrive]

I would take a tooth brush, and plain water, and scrub the igniter. I would also ensure that the parts the disperse the gas are aligned correctly.