weird timing light problem. Any ideas?

[H-K]

383 sbc TBI using ~1991 350 donor ignition parts

When using a timing light, I see several marks at once on the balancer instead of one clear mark. The balancer has only one actual mark on it, but when the engine is running, it looks like it has at least half a dozen marks showing up. I've been searching around the net for answers and am coming up empty. Maybe I need better keywords or something, but I'm not finding much. One thread suggested that multi-spark coils can cause something similar to this, but the coil just looks like a typical delco unit and nothing hi-perf aftermarket. I bought a new timing light thinking that was the problem, but no dice. Any ideas? I'm scratching my head raw on this one. thanks

 

[Spork]

Are you on cylinder #1? Just a thought.

 

[H-K]

Yeah, definitely on #1 and tried things like moving the pickup clamp to a different part of the wire, checking that the wire was separated from other wires and metal and wasn't arcing, etc. Made sure the ESC was disconnected.

 

[Kevin B.]

Probably just funky reflections from imperfections in the pulley you can't see with the naked eye. Mark the real notch with some whiteout or something - if that's jumping around then you'll know you've got a real problem.

 

[H-K]

Yeah, picking up some whiteout on the way home from work today. Thanks for the suggestion.

 

[Bart]

Probably just funky reflections from imperfections in the pulley you can't see with the naked eye. Mark the real notch with some whiteout or something - if that's jumping around then you'll know you've got a real problem.

Yep, we always used a grease pencil.