On Tue, 17 Jan 1995 SDTilton@aol.com wrote:
> So I dug into the ignition parts box and tried out a couple of differnt coils
> with better connections on them. They worked like crap!!!! A few hundred
> yards down the road the engine would start missing. I'd let it cool off a
> second and then it would run fine for another couple of hundred yards.
> I remember some of them having external restors on the mounting brackets.
> (which I did not include in today's coil swapping sessions)
>
> Scott Tilton in Richmond VA
Coils that are intended to have external ballast resistors are not meant
to run on 12 volts for extended periods. When you start the car, 12v is
supplied directly to the coil, bypassing the resistor, for a hotter spark.
When the engine starts and you release the key, the key returns to the
"run" position which puts the ballast resistor in series with the coil.
The resistor drops the coil primary voltage below 12 volts when the car is
running. If you ran coils that were supposed to have a ballast resistor
in a car without that resistor, they probably overheated rather quickly
because the current through the primary windings was too high.
Ray Gibbons Dept. of Molecular Physiology & Biophysics
Univ. of Vermont College of Medicine, Burlington, VT
gibbons@northpole.med.uvm.edu (802) 656-8910
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