As I have stated many times, a multimeter can give misleading impressions
when used to measure resistance of HT circuits.
You have about 40Kv in the HT side of the coil. THis is enough to easily
cause a spark across the plug under pressure. But it is also enough to
cause a spark across a break in the HT winding of the coil, a break in
resistive plug wires, and most importantly, between the rotor arm and the
electrodes in the cap.
So, you can measure infinite resistance with a multimeter in the HT side,
yet it will still work.
When I worked at Lucas (late '70s), the specification for coil winding
allowed up to 3 breaks in the HT winding. The ends would be twisted
together, with the insulation still on, knowing that it only takes 100
volts or so to break down this insulation -- so a new coil could measure
infinite resistance in the HT side.
Simon
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Simon Matthews Avant! Corporation
Phone: (510) 413-8820
Fax: (510) 413-8080
E-mail: simon_matthews@avanticorp.com
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