Tom -
It sounds to me like you have installed the white wire (primary
ignition wire) around the metal U incorrectly.
It is supposed to be looped around the U, so that every time the coil
fires to a spark plug, you get current in this wire, which in turn
sends a magnetic pulse into your tach through the metal U.
Because the magnetic pulse is bi-polar, if you install the white wire
loop backwards to the way it was before, then the Tach will not work.
You must reverse the pulse direction of the loop and then it will work
(you do this by turning the plastic piece around 180 deg while keeping
the same loop)
I am a little bit confused, however, because you cannot loop this wire
unless it is looped through the plastic piece, which you do not
mention in your email. This leads me to believe you may not have
looped the wire at all? Please confirm. There is a little hole in
the plastic piece in which the white wire is supposed to be looped.
The piece, when mounted on the back of your tach, should be:
bottom: plastic piece (it is unidirectional so it only fits on one direction)
top: metal U
looped around both: white wire
fixed with: brass thumb screw.
Hope that helps.
Alan
'53 BN1 '64 BJ8
On 3/10/06, tom felts <tomfelts@earthlink.net> wrote:
> 65 BJ8, P2-----Tach.
>
> I removed all dash gauges recently to install a new dash. Put everything
> back together and now the tach doesn't work.
>
> I have insured the ground is connected and the two wires are connected.
> The only confusing part is the white wires that are tied together with a
> white plastic holder that fit over a connecting screw. Two things fit over
> that screw--the plastic white wire holder and a U shaped metal connector.
>
> I wasn't sure if it (the white holder) went on before the metal U shaped
> piece or vise/versa. When I first put it on during re-installation, I put
> the plastic white wire holder on first then the U connector. Tach didn't
> work. Reversed and put the metal U connector on first and then the white
> holder. Tach still didn't work.
>
> Any ideas? Did I screw something up inside the tach when I inserted the
> metal U connector all the way inside the tach?
>
> I could almost swear when I first removed it before adding the new dash
> that the metal U connector was on first and then the plastic holder.
>
> The tach worked perfectly b/4 I removed it. The car has, and had before,
> a Pertronix.
>
> TIA for any advice.
> Tom
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