Make sure you have power to coil + WHEN CRANKING
Measure power to coil + both with key in "run" and in "crank"
With power in "run" disconnect distributor connector. Take the engine harness end of the connector, and tap the exposed terminal onto ground. Each time should produce a "snap!" spark at the coil
Remove/ and work all connectors in/ out several times to scrub the terminals and "feel" for tightness, ESPECIALLY the distributor. Examine them with a flashlight for corrosion
Remove cap, inspect for dirt/ water in cap, rotor "punch through." Inspect the reluctor/ pickup for damage, rust, debri, and shaft wiggle. Set the gap I've forgotten, .008" I think. INCHES, not mm. Make certain the reluctor and pickup don't touch. TB above already posted checking for AC voltage
MAKE ABSOTLUTELY CERTAIN that the ECU is grounded!!!
Measure coil + voltage with key in run........should be no less than say, 6V and no more than, say, 10V. Measure coil NEG it should be quite low, say, 1-3V or so. If you have a tach DISCONNECT THE tach wire for testing. The tach may be shorted