John Haskey wrote:
> According to my mechanic I need a new leading igniter for my
> '85 gsl-se. They seem kind of pricey. What's inside an igniter?
It's potted in poured epoxy, so not a serviceable part. There's an
excellent chance of a ****d IC die so there wouldn't even be a part
number to look up. I haven't run across any posting re****ting
reverse engineering the circuit, or detailed info from a manufacturer,
so what follows is from consensus guesswork and some observation.
Mostly it's a switching transistor that turns off the current through
the coil primary when a spark is desired. In my '87, the igniter
also includes a timing circuit that decides on its own when to turn
back on and start building up stored energy for the next spark.
I believe it maintains a constant duty cycle (dwell angle) regardless
of RPM, in direct emulation of (ideal) mechanical points.
These models probably don't include a current limiter in the igniter,
which would greatly increase worst-case heat dissipation in the igniter.
Car makers are extremely conservative, so cling to what has worked
well so far like external resistors or carefully chosen coil resistance.
(No resistor shows on my schematic.)
If the igniter is attached to the coil then a used coil on Ebay will
probably be sold with the igniter, lots cheaper than a new igniter.
If your car is unusable, look into swapping the leading and trailing
igniters -- the trailing ignition is a lot less im****tant, and I think
is even shut off in normal driving on your model.
Describe the symptoms if you want our opinions on whether the igniter
or the mechanic needs replacing.
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