Hi all,

I was attempting to using an inductive timing light to diagnose a rough idle issue and got some interesting results.

Testing #1, timing light shows erratic spark, looks to fire "multiple times" on occasion. Using an inductive tacho shows rpm ranging between 700-1000+ (i.e. also measuring the apparent multiple sparks).

Testing #6, timing light regular spark and inductive tacho pretty solid at about 700rpm.

Note that leads, plugs, cap and rotor are all new or relatively new. Also if I open the throttle a little #1 smooths out. So either some cylinders are firing very erratically (and causing my rough idle) or the inductive tools are reading spark incorrectly? Interested to hear opinions.

Thanks,
J

i assume you bridged the two points in the diagnostic connector?

Maybe the wire is not on the connectors properly?

No, I was looking for a regular / consistent spark and not overly concerned with actual timing.