So I replaced all my ignition coils and sparkplugs but decided to take a closer look at the removed components to see if I can determine what is causing the studdering problem. I believe the design of the coil boots is generally bad because it uses a thin wire spring for contact instead of using a split hard tube connector like on other brands such as BMW. For some reason, the spring contacts develop a white powdery residue over time that inhibits electrical transfer. If you simply clean this out, you will have better performance. See picture to understand what I am talking about. My sparkplugs were tight and this is not gas blowby. All ignition coils had this buildup, more so on the boot to coil connector side than the boot to sparkplug side. This is on a GD3 with 87k miles.

 

Good info, GQ.

1) What did you clean them with?

2) You say, "If you simply clean this out, you will have better performance." Will cleaning them provide performance as good as replacing them (for those of us who need "best" instead of "better")?

3) Are there any signs that the springs with white powder have weakened with age?

Thanks.

 

I cleaned it with an old toothbrush and isopropyl alcohol. I strongly suspect that the ignition coil heads are fine but that this buildup interferes with electrical conduction. Cleaning it should give you the performance before degradation. The springs have not weakened though the surface finish is no longer the same. The plastic has gotten a bit more brittle. Be gentle when taking the boot off.

 

interesting investigation, but unfortunately, one can't draw any conclusions from your findings to date. Clean your old ignition coils and reinstall them. Let us know how long you get additional usage from them. After a few others do the same, we'll have some kind of baseline to work off of. Until then, I'd choose to put new parts in so I don't break down in the second lane of some god-fore-saken Cali highway with idiots buzzing by me at homicidal speeds.