msd install
 

I installed an msd unit today and one problem arose. The tach does not work. In Wayne's 101 projects he says to hook up the black with a purple stripe from the cd box connector to the tachometer output on the side of the msd unit. I have a 3 pin connector, one red and two white wires. Can anybody tell me what to do to get the tach running?
Tom

do you have the MSD convertor box for the tach signal ??

Wait wait wait. Don't use the tach adaptor unless you need to. Some cars definitely do not need it.

What you need is to find the tach's black/purple wire. Wiring diagrams for other cars are at http://www.pelicanparts.com/911/911_Parts/911_electrical_diagrams.htm

If anything, your car will be like the '73. That appears to have the tach wire running from the points.

I did the exact same thing and the tach stop working. I have a 1973 911T

I did install a tach adapter, does this mean i could have messed up my tach? Would it have worked if i never installed a tach adapter.

Would it still work if I remove the tach adapter?

Iam thinking of sending my tach out to North Hollywood Speedo to change the circuit board in the back side of tach.

On my '77, the tach works by connecting the MSD tach output to the black/purple wire on the white, plastic, "t" shaped, three way connector that comes-out from under the metal electrical regulator panel. It appears from the wiring diagram that the output from the distributor points splits: one wire goes to the white trigger going into the CD box, the other goes to the tach via the white plastic connector.

Thanks for all the info guys. I found the wire. It is right where ejc-77-targa said it is. I was told from a certain Steve from Oregon that it is in there. Just traced the wires from the 3 pin cd plug back until I found the black with purple wire. I originaly hooked it up without the tach adapter and it ran fine, at least I thought. The readings were not consistant. I then put the tach adapter in with much better results.
Tom