[325high]

Thanks.

[J02 335i]

No, not at all. A bad coil is a bad coil or computer problem (not sending a ground signal to fire the coil/plug)

[325high]

Good, thanks. And this is a stupid question but the spark plug screws into the engine, not into the end of the coil, right?

[galahad05]

Yes, that's right. The spark plug screws into the cylinder head, with the electrode protruding into the combustion chamber of a cylinder.

There is one possible side effect of a bad ignition coil: fouled plug.
Why?
If the coil was simply not producing any voltage/not enough voltage, what you have is a cylinder where the spark plug was misfiring. This leads to plug fouling.

If you have a fouled plug, this is easily correctable; just pull the plug and clean it, put it back in.

[J02 335i]

Originally Posted by galahad05

Yes, that's right. The spark plug screws into the cylinder head, with the electrode protruding into the combustion chamber of a cylinder.

There is one possible side effect of a bad ignition coil: fouled plug.
Why?
If the coil was simply not producing any voltage/not enough voltage, what you have is a cylinder where the spark plug was misfiring. This leads to plug fouling.

If you have a fouled plug, this is easily correctable; just pull the plug and clean it, put it back in.

I'm pretty sure that fuel will shut off to the cylinder that has lost spark, resulting in a spark plug that should not be fouled, also I was under the understanding that platinum spark plugs should not be cleaned or re-gapped.

[galahad05]

Originally Posted by J02 335i

I'm pretty sure that fuel will shut off to the cylinder that has lost spark, resulting in a spark plug that should not be fouled, also I was under the understanding that platinum spark plugs should not be cleaned or re-gapped.

Yeah, you're probably right, the DME should be smart enough to kill the fuel to the cylinder--IF it can tell that the coil went south.

You can surely clean platinums.
Here's an easy how-to (for any plugs, including platinums): http://www.ehow.com/how_5099351_clean-spark-plugs.html

[J02 335i]

Originally Posted by galahad05

Yeah, you're probably right, the DME should be smart enough to kill the fuel to the cylinder--IF it can tell that the coil went south.

You can surely clean platinums.
Here's an easy how-to (for any plugs, including platinums): http://www.ehow.com/how_5099351_clean-spark-plugs.html

I think that is kinda old school spark plug cleaning lol, like if your snowmobile were too foul a plug. They told us at trade school to never gap or clean platinum spark plugs, it had something to do with the coating coming off the plug. I could be wrong, I just vaguely remember something about this.