Originally Posted by CycleDoc59
Resistance can be in plug wires (carbon thread core), plug caps, and/or
the spark plugs themselves.
The primary purpose is reduction of stray electromagnetic interference;
mostly with radio-type communications... But, those stray currents can
cause backlash problems for on-board systems; CDI units, computers and
With the simple Kettering system (battery/points/coil) no resistance is needed
except for radio interference. Not so with modern no points, high output systems.
Also, resistance in plug wires depends on length and resistance per foot; change length,
change wire type, change resistance.
So, changing the original amount of ignition system resistance can cause
This is exactly what I need to know.I just don't don't know what wires and caps to use.I know that my plugs are NGK DPR8EA-9 which I believe to be non resistor type plugs.The problem I am having is an occasional back fire on the left bank and an occasional dead left cylinder.Coils check out,CDI has been swapped to a known good unit,and crank triggers have been swapped out for known good units.Oh yeah,plugs have been swapped several times for new ones.Battery and R/R has tested good.I did the relay mod to power the coils directly from the battery,and ran new grounds directly from each coil mounting post to the battery negative terminal.All connections are clean and secure.The only thing I haven't changed is the coil wires and plug caps.7mm is the largest wire that will fit down inside my coils on the screw posts.