OK the timing light clipped onto the L1 wire and the timing marks bounce around (like 10 degree bounces). Switch the light to the T1 wire and the marks are steady.

Tried switching from 2nd gen coil back to original coil same issue.

Installed MSD 6A driving 2nd gen coil same issue.

Switched ignition wires same issue.

New plugs same issue.

Running a locked (springs removed) dizzy. I was wondering whether the weights may have been getting stuck and freeing up but that would effect my T1 reading as well I think.

Has anyone had this problem?

 

Just to not leave this open ended... Robert from rotary shack told me to get a new timing light. I had an old sunpro inductive. I bought a new inductive one last night. He was right it fixed the problem.

 

Thanks for posting. I've seen the marks jump around. Perhaps it was from a cheap timing light.

 

yup yup yup. thats the reason why I have 2 craftsman (regular and advanced) for second opinion.

 

Guess what. Went for some tunning runs came back and she's doing it again with the new gun. I'm going to create a new thread with video of my setup and I'll show whats going on.

 

video

https://www.rx7club.com/1st-generation-specific-1979-1985-18/video-my-12a-blowthrough-762325/

 

When you say, "locked dizzy with springs removed", did you have the weights welded?

 

Just the springs removed.

 

weld the weights and make sure the stainless steel cap installed inside the distributor.. the mag pickups can pick up interference if the cap is not there

 

Cap is there but the weights arent welded. Will do.

 

Robert, that's aluminum. Too much cheese today?

learner, another cause of the timing mark jumping around could be the pickup itself. I tested this phenomena with several ignitors hooked to the offending pickup and they all jiggled under the timing light. I tried another pickup and the mark was stable.

 

Isolating the L1 wire from all the other wires and cliping the new light in a spot where it was furthest away from any interference source reliably solved the issue yesterday.

Thanks guys I appreciate the input.