71stang99

http://img.photobucket.com/albums/v3...9/IMG_1508.jpg

I am trying to get my tach to work (72 Mach), I am using the 6AL2 box and MSD 8477 dizzy and bought this adapter since the tach wont work, I have the instructions but when they show it should be connected (using the current triggered tach diagram) white to white, black to ground, and the red to the trigger wire (original coil + wire)

Looking at the picture in the link, the original setup uses the ballest resister, one of the wires on the right is key on +12 and the one wire on the left is engine on +12 and I think the other wire on the right is what came from the coil.

So where would I attach the wire for the tach adapter? will it still need the resister?

thanks

kalli

the instructions are pretty clear:
http://static.summitracing.com/globa...0_frm28572.pdf

your picture doesn't tell me much. but the first thing you should do is to redo the connector on left side of ballance resistor. that cable seems to touch (or be about to touch) the clamp that holds resistor to chassis

if you have a original tach like indash or rally pac (i don't know about 72) and MSD distributor with magnetic pickup then you'll have to use the first wiring diagram in manual

white to msd box tach output
black to ground
red to the cable from ignition switch to red of MSD (not the heavy red to battery),one of the tach cables goes there as well
and violett to the other side of tach cable

71stang99

The picture was taken from when I had the motor out last year and the wiring was fixed. So I would use the voltage triggered diagram vs. the current triggered diagram? I was told to use the current wiring configuration which does not use the violett wire.

thanks

kalli

to be honest i wouldn't know. it depends on the tach.
if it's current or voltage triggered.
the old fords have voltage (series) triggered. those tachs where hooked between ignition switch and coil+ inline. i don't know if the 72 still has that or not :-(
i'll check the wiring diagram, maybe that has info

edit: the wiring diagram in the FAQs doesn't mention the Tach. bummer. i read on another post however that someone found in a 73 shop manual the info it's originally wired from ignition switch to tach and the other cable at tach to coil+. that's just what i suspected. so if your Tach was hooked up in the same way before you put in the msd, then yes, the voltage/series triggered diagram is the way to go
if you don't know then I'd suggest opening a new post to find out if the 72 tach is series or current triggered. some fella around here with a 72 will know how its originally wired

kalli

what I'm saying is, if you remember how the tach was wired originally and it was inbetweeen ignition switch and coil+ then you'll have to go with the series (voltage) triggered setup