Hi Ernest;


> Todd,
>   What kind of plug wires are you running there?

They are a custom made plug as the GM 'vette coils don't fit a standard plug
wire. I seem to remember the parts guy saying that all the plug wires are
suppression these days, however there is no marking on the wires to confirm
this.
Anybody who is yet to order the EC2 should know this when deciding whether
to have it set up for Mazda coils or GM coils. When I made my choice I
assumed it would be a no-brainer. Knowing that the Mazda coils are expensive
and assuming they may be hard to find, I figured that the GM coils would be
a cheap off-the-shelf product, available from any number of aftermarket
parts stores. They are anything but. This is not to say that they won't work
well, but just a heads up, that they are not as easy & cheap to use as might
be expected.


>
> So, with this theory:  Your timing light might be working because it's
> pickup is more sensitive.  That could be because it has more wraps of
> wire in it's coil, or because it has a more expensive transistor.  Or
> it could have a Hall Effect transistory and the tach not.  But it's all
> to say that you're not emitting enough noise for the tachs, even though
> there is enough for the timing light.

A quick inspection of the inductive pick-ups on both instruments revealed
that the timing light has far more wraps of a much finer wire than on the
tach.

>
> Try using an unshielded wire on one plug that you attach the tach to and
> see if you get any response.  If the tach works on your car, try pulling
> one wire from there for just a few minutes as a cheap test.

Good idea, but as pointed out above, the standard plug wires won't fit on
the GM coils :-(. Now with that said, I must confess that I haven't even
tried a standard plug wire. When I bought the coils and asked for wires, I
was informed that they wouldn't have anything to fit them, but they were
able to have some made up and shipped up next day at no extra cost.
This is the unfortunate thing about having the airplane at the airport.
It's not as easy to quickly try new things, when good suggestions come in.

S. Todd Bartrim
Turbo 13B RV-9Endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm

   "Whatever you vividly imagine, Ardently desire, Sincerely believe in,
Enthusiastically act upon, Must inevitably come to pass".