berlinetta85

I had ignition trouble the other day and I pulled the cap off and found dust under the cap, which was causing my weak spark... where is this dust coming from? The cap is barely a year old... any isight on this would be greatly appreciated.

Vader

85,

Was it truly dust, or a thin film coating? The high voltage created by the coil will ionize the air in the distributor, creating ozone gas. This gas can be conductive, and will cause the spark energy to dissipate to the easiest ground path. In this process, the metal from the contacts in the distributor cap and rotor will deposit a thin metal film (dust) all over the inside of the distributor. I see this kind of thing all the time in high voltage switchgear, and it can be a real problem if not cleaned. Nothing worse than seeing a 1000 KVa susbstation going BOOM as the utility tries to maintain voltage in the system. On your car, it can kill the spark, which is just a little less severe.

berlinetta85

Thanks for the insight Vader.... the cap had a light film, but it was everywhere inside there. I cleaned it off with some WD40 and wiped it down and scraped off the deposits off the leads with a screw driver and the car fired right up as when I first put the cap on.

I was just curious as to wether this is a routine thing that must be taken care of regularly or if I had something wrong with my distributor...

maybe you could answer that one for me as well, I'd appreciate it.