Ditto Ken's reply. You're right in following up the ignition LT
components - that is exactly what your tach is telling you by bouncing
around. If you notice your ignition warning light flickering as well then
you are losing the 12v off the white i.e. could be the ignition switch or
wires to and from it.
Also the ballast 'resistor' is really a length of resistive wire contained
in the loom. It starts as a white near the fusebox or ignition relay and
ends up as a white/light-green at the coil. You may also notice a 2nd
white/light-green at the coil, this goes to a special spade on the solenoid
that supplies a full 12v to the coil during cranking. Don't run the coil at
a full 12v (if you were thinking of bypassing the ballast) for any length of
time or you will burn the points and overheat the coil.
Instead you might like to try this test: Try putting a test-lamp on the
coil +ve. You should see a steady flickering or glow at idle, and if it
gets brighter momentarily with the misfire then you are losing the
connection through the coil and points to ground, whereas if it gets dimmer
momentarily then you are losing the ballasted 12v to the coil. If it gets
brighter then connect it to the coil -ve. If it still gets brighter then it
is the points or the wire to them. If it gets dimmer then it is the coil.
PaulH.
----- Original Message -----
From: Trefor Delve <tdelve@mathworks.com>
To: <mgs@autox.team.net>
Sent: Friday, March 10, 2000 12:43 PM
Subject: Ingnition woes ...
> All,
>
> Short preamble before the question:
>
> So this last weekend, I replaced the points and condenser on my 74.5 B.
>
> Since then, I've been suffering from intermittent misfiring. Now, it
> seem to point to ignition rather than fuel as the tacho jumps all over
> the place during the misfire.
>
> I've gone back to the old condenser in case the new one was breaking
> down, but the problem persists. For the hell of it I'm going to put the
> original points in just so things were back to how they were.
>
> The question: if I'm right, (and I don't have my manual infront of me)
> the 74.5 were 6v coils with a ballast resistor. Where's the resistor?
> Is it resistive wire or a single component?
>
> I'm thinking I may have disturbed some suspect wiring and can be sure by
> going straight from the ballast resistor (temporarily at least).
>
> So much for preventative maintenance!
>
> Any thoughts?
>
> Trefor
>
>
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