This really pertains to my LJC, a 1981 Toyota Corona, but may be
instructive to all regarding the function of ballast resistors.
Several months ago I installed a Crane XR-700 ignition on the Toyota,
and also installed an aftermarket high-voltage coil. (Allison
Permaspark
was once installed on the TR6 WITH a ballast resistor)
The directions with the Crane XR-700 did provide a procedure for
determining whether the car's ignition system included a ballast
resistor, and in so doing, provided a way for me to decide whether or
not to install a ballast resistor. I concluded, as a result of
following these instructions, that I SHOULD use the ballast resistor.
Well, I noticed right away that the car became very difficult to
start. And I immediately noticed a pattern. When cold, I would have
to crank it for as much as 15 or 20 seconds before I would get it to
fire, but the big clue was that it would always fire JUST AS I
RELEASED the key. That is, the INSTANT I let go of the key and let it
snap back to the 'on' position, the engine would start. At first I
thought it was a coincidence, but it kept happening time and time
again. Having just learned that ballast resistors function or don't
function depending upon whether the starter is operating, I arrived
at a theory. To test that theory, one morning (prior to starting the
Toyota) I bypassed the ballast resistor that I had installed. I got
in, turned the key and BAM. It started up INSTANTLY. My theory was
correct, although it does leave me with some questions. What I
concluded is this: What was happening was that when I had the key in
the 'start' position (starter operating, of course) the resistor
would function and reduce the output of the coil. The engine didn't
want to start with the weak spark. But the instant (and I mean
INSTANT) I let go of the key, the starter would switch off, the
ballast resistor would be, in effect, removed from the circuit and
the coil would be allowed to produce full spark again. The engine
would still be rotating and would have just enough momentum to start
now that it had full spark. Having proven my theory, I removed the
resistor altogether and it's started up first try every time since. I
have checked the coil after running around town for a while to see if
it gets overheated, but it barely feels warm.
What I don't understand is why the above scenario seems backwards. My
understanding is that the resistor is SUPPOSED to function once the
engine is RUNNING. (key in the 'on' position) It's supposed to be
switched OUT of the system when the starter is operating (to allow
full spark for easier starting) and then switched back INTO the
system once the key is released to the 'on' position. In the case of
the Toyota, it was apparently switching the resistor INTO the system
when the starter was operating and then the resistor would be
switched OUT of the system once the key was released to the 'on'
position. I don't understand this, but I'm sure there's a good
explanation for it.
Any input would be greatly appreciated.
--
Pete Chadwell
1973 TR6
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