[TCML] Ignition Coil Won't Spark from Mosfet but DOES spark By Hand??? HELP!?

[Jim Houx <pha3zme@xxxxxxxxx>]

Hello everyone,

I'm new to this list.  Please be gentle! :)  I came because I can't find
the answer to my problem from googling.  And the problem is mind-numblingly
simple.  I just can't see what is going wrong!  I thought maybe some
experienced high voltage people could help.

I'm trying to get an ignition coil to create sparks running it with a
Mosfet powered by a 555 timer.   The Mosfet is definitely switching.  I
checked it with resistor, ampmeter, and o-scope.  Everything is behaving
predictably but when I use it to power a car Ignition Coil, I don't get any
sparks.  I can tap the terminals of the Ignition coil by hand -- Even with
it connected up to the mosfet circuit -- and get sparks.  But when I try to
let the mosfet drive it, there are no sparks.  There is definitely current
flowing.  And if I change the frequency to super low (like a pulse every
second), the ampmeter is registering the pulses.  If I change the frequency
to super high (like 100khz), I get averaged current flow on the ampmeter.
But I don't get sparks!!!!!  I also switched out mosfet with other kinds
(different ratings).  Didn't fix it.

Anyone else ever run into this problem???

Here's a schematic similar to my setup:
http://www3.telus.net/chemelec/Projects/Car-Coil/Car-Coil-1.png

Hope someone else has had this problem before and can help!!

Thanks,
Jim
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