green zr1

anyone know how to tell if your opti spark has a bad cap and rotor or optical sensor, i'd hate to change cap and rotor then found out i need a whole new unit any information would be helpful

Injuneer

If the problem is with the optical sensor, it will set trouble codes for loss of low resolution and/or loss of high resolution pulse pattern. If its a high voltage section problem (cap/rotor), there are no direct trouble codes, but if your car is OBD-II you should be seeing the misfire code.

Might want to add a "signature" showing at least the year of your car. Most people will include year, make, modle, tranny and any major mods.

1FstFormulaV8

If you own an OBD-I car, you're kind of in the dark. If you're willing and brave. Check the spark coming from the opti. Though, it might not be as effective if you have bad set of wires. What symptoms are you having with the car? We need to know before we can make a better diagnosis.

green zr1

my car is a 95 z28 4speed auto, has no spark to number 7 cylinder change plug and wire 3 times still no spark and no trouble codes