(no subject)

[Huw Powell]

> I found and bought an external tachometer with shiftlight for my 90q. It will
> (amazingly) work with Five cylinders.
> 
> The Tach as four wires: red, black, white and green.
> 
> Red and black were obvious, and straight to the battery. 
> 
> GREEN is the tach 'imput signal'.  The instructions say that this should be
> wired to the negative side of the ignition coil.  So, I popped off the cover,
> popped off the nut, cleaned up the contacts and attached it there.
> 
> No action.  Nuttin.
> 
> So I'm left wondering...where does the stock tachmeter recieve it's signal
> from?  is it the same spot...or somewhere different.  The instructions seem to
> give the idea that if you tap into that wire you will recieve a good signal for
> the external tach too.

the tach runs one of the few wires in the car with three colors -
R/Bk/Y.  identifiable, or at least it should be, at the coil, if not it
is available at the oil pressure warning control unit, the fuel pump
relay and, of course, somewhere on the way to the stock tach.