On Sun, 13 Dec 1998, K. Lee Lerner wrote:
> When I test for current coming from the coil to the distributor I find no
>evidence of current. There is also no spark when I place the wire going from
>the coil to the distributor next to the engine block.
>
> Am I running the proper tests?
That depends, how are you testing for current at the coil posts?
I suspect you have a problem in the low-tension circuit; that's the part
of the ignition that charges the coil. When the coil discharges the
electricity is "forced" through the high-tension lead and you get a spark.
First, make sure you have points ignition. I'm not very familiar with the
Spitfires, and if it's electronic ignition, then many of these suggestions
just won't be possible.
There are a couple of places in the low-tension circuit that are prone to
failure. The first and most often is the condensor; a little metal
cylinder that lives inside the distributor cap. Get another one and try
replacing it (get two and carry a spare). If this does not cure your
problems, take the distributor cap off and watch the innards work as you
crank the engine. Alternatively you can turn the engine over slowly (with
the ign. key out, good to remove spark plugs too) and make sure that the
points are set to the right gap. If the points do not open, or the gap is
incorrect, file them (with a points file!) and re-set the gap to the
proper spec.
Also, there is a small wire that connects the coil to the points; it is
braided copper covered with cotton insulation. It has a tendency to fray
and ultimately snap. If yours looks ancient or frayed, replace it. You
could probably get away with a homeade patch cable to get the car going,
but it's best to have the (VERY flexible) proper cotton-covered part.
That's pretty much the entire low-tension system checked over. If you
still have no spark, make sure you've got voltage (from the ignition key).
Although I'd expect you to have a "more dead" car if the keyswitch is
broken.
If the whole low-tension circuit checks out OK, it's time to check the
high-tension circuit. Not much to check here, and I doubt that it's your
problem... but make sure your distributor cap & rotor are in good shape,
that there isn't any contaminants on the metal traces inside both, and
ensure that all the wires are seated in their bosses.
Also, make sure you have an adequate grounding strap between frame
(battery) and engine. No ground strap = an incomplete circuit = no
sparks.
-Malcolm
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