Do this Don,
mark which wires go where on the coil currently.
with the engine off, but key on, find which one of the individual wires has
'key on' power on it.
Expect it to be a black wire.
It should be a black wire, medium size.  Not as small a wire as the ones to
say, the rear side marker lights - one step on the wire size over that.
Find that wire.
which ever coil terminal that wire goes to,
take your tach signal off the other terminal.

Scott

----- Original Message -----
From: "Don Hanson" <dhanson928@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, October 12, 2009 11:32 AM
Subject: Electrical question (Coil terminals)

> Hi all, I am looking to find the Neg pole terminal on my coil.  Mine has a
> plastic cap on the top meaning I would have to get the coil all the way
> out,
> take off the wires and then get that cap off to see if it has (+) and (-)
> marks on the top, like most of them do.  Trouble is, mine was mounted by
> the
> PO in such a way that it's a real pain to get off to remove the wires to
> get
> the 'cover' off.  So, is there a way to tell which is which?  Mine is a
> conversion rabbit motor, so the wires probably aren't familiar or color
> coded.  They look the same size.  One terminal goes on to the hall sensor
> or
> the MAF box or somewhere...Two go over to the ECU or at least into the
> harness to the ECU.
>  With the key on, each terminal shows battery voltage..Same
> (polarity?)..With the motor running and the alternator engaged, one shows
> 13.3v and one stays at battery charge voltage.
>
>  I am looking for a place to get a signal to my tachometer.
>  Which of the terminals is the "Low Voltage" or the "Neg" terminal, given
> those peices of info, can I tell?  Or do I have to take the coil out
> (difficult) and remove that shield and actually look for a marking on the
> coil itself?
>
>  Thanks,  Don Hanson