vette75406

Mine is missing , from bubba's work , my tach works fine so what is its purpose , I assume it just filters the rfi signal , thanks

mrvette

Yes, that is what it does, it'a a 2 pole pi network, schematic on the forum here somewhere, do a search.....

what is does is integrate the pulses from the tach 'points' or sending unit side of the coil, any coil does what's known as 'rings' when pulsed the first shot is what fires the plugs, but it's the after effects on continuing ringing, that the filter takes care of, I suspect they did it in an external part from the tach to minimise RFI into olde tyme AM radios.....otherwise it really should be part of the tach circuit board itself, as in all aftermarket tachs....maybe it was an afterthought, but it's used throughout the GM line for years now, and I suspect that RFI is the reason.....

GENE