So i have a 94 camaro z28 that i did a rebuild on 5 or so years ago, including replacing the cap and rotor on the opti spark. Well I have been having trouble on fixing an arcing problem on my coil and all wires. As i was looking at the wires and opti spark, i noticed on the cap that it has the hole on the bottom like the 95 and older VENTED opti spark has. Is there an interneral difference on the cap between the 94 non-vented opti spark verses the 95 vented opti spark? Would this make my car arc and run poorly?

 

no but that hole would let moisture in and make the opti not happy. the main part (optical reader) that fails in the opti is not in the cap its in the base of the opti. may be a good time to replace the it.

 

Replacing just the cap is usually an exercise in futility. Once arching takes place, the ozone generated degrades the internal electronics and optics, so that the entire Assembly has to be replaced. You could get ambitious and try to clean the optical stuff, but even if it works out, I am not sure how long it will last.

 

i had plugged the hole when i originally put it on, so hopefully it kept the moisture out. but yes, ya'll prob right, bout time to replace the opti. let me ask another question. If all my wires and coil are arcing and the car is running rough, would this make it smoke and smell real rich?

 

Oops, didn't want to do that. That's a vent hole, just a passive one, but the opti does need to be vented one way or another. And yes, a misfire like you're getting can or will make the engine run rich. If you replace the opti, I'd seriously consider "updating" it to be positively vented like the new style opti. Here's a good how-to: Opti-Spark Options