electrical help request (no spark)

[Dave Glubrecht]

Car is an 86 4kq.  It quit while running.
Diagnosis revieled very little (but some) spark.
OK, I lied in the title, it does have a little.
I have many test parts along with an 84 4kq to compare against.
The weak spark will only jump ~ 5mm.
I tried a test distributor with no change, verified good in 84 that will
run.
I tried a test ignition control unit with no change, verified good.
I tried the coil from the 84 with no change.
I checked voltage both at the coil and the ignition control unit.
I ckecked ground from the ignition control unit.
I disconnected the wire from the coil to the fuse box in case there was a
short in the tach or something.  No change
I disconnected the oxs computor as there is a wire from the ign control unit
that goes to the oxs computer with no change, I verified that a car should
ba able to produce spark with the oxs computer disconnected on the 84.  The
84 had good spark with the oxs computer disconnected.
I checked continuity on all the wires in the system.
I am frustrated because I think I checked everything at least twice and
still have very little spark.
With a few connectors and a little wire, I think I could get spark out of my
test parts easier than this car.
Please help.  I do not know what to check next.

   Dave G