Re: Power pack or coil?
Bert..... Having retired some years before that engine came into existence, I'm somewhat unfamliar with the design of the components circuitry, and hopefully you've tested the spark by having the s/plugs removed and testing the spark at cranking speed using some kind of tester whereas you can set a 7/16" gap. If not, do so.
The spark should jump that gap with a strong blue lightning like flame.... a real SNAP! Does it. If so.......
As you've explained above you've pretty well eliminated the coils as being suspect. Now, to seperate the timer base from the powerpack as being suspect, I'd suggest the following.
The timer base wires to the powerpack (if memory serves me correctly) are color coded to the related cylinder, depending on which bank as: Blue = 1 or 2, Purple = 3 or 4, Green = 5 or 6.
Whichever cylinder you're having no spark on, switch those wires accordingly.
Now, if you have spark on the coil that was not previously firing, suspect the sensor (timing base).
If no change in whatever coil was faulty (same coil has no spark), suspect the powerpack.
However..... The problem you're encountering could also be due to a pin/socket being pushed back too far in its rubber plug, a broken or frayed wire at these same plugs, something of that nature. Let us know what you find.
