1972 P1800ES Tachometer connection

[142 Guy]

So we have a bit of confusion. The terminal on the ignition coil that you want to connect to is the negative #1 terminal. The 15 terminal is the coil positive with the two brown wires.

The problem is that the #1 terminal has two wires on it. Normally there would only be a single wire which would lead down to the distributor. You need to sort out which of those two black wires is going down to the distributor points connection and insert the tach in series between that wire and the coil #1 terminal.

You also need to figure out what that other wire is doing that is connected to the coil #1 as it may interfere with the operation of the tachometer. Was a more conventional voltage sensing tach installed in the car at some point? That black wire with the red insulator on the terminal is clearly not stock and might be an added wire for a more conventional aftermarket tachometer.

[Grahamwhitfield]

Thank you to everyone that has helped me along the way in the aspect of wiring!! I can now say I have a working rev counter in the ES!!

I have connected it up as my very crude picture illustrates. With the tach in series between the coil and distributor.

The ‘second’ black wire mentioned in the previous post goes to a little round cylinder on the side of the coil, about the size of a d size battery. No idea what that is? In the picture I have shown this as a green line to make it easier to see.

But end result is the tach is working as it should and has no visual interference evident. Very pleased and thank you all again.

[Derek UK]

Glad you have it working. The little pot (green wire) is an anti interference suppressor.

[25PSi]

Originally Posted by Grahamwhitfield

Thank you to everyone that has helped me along the way in the aspect of wiring!! I can now say I have a working rev counter in the ES!!

I have connected it up as my very crude picture illustrates. With the tach in series between the coil and distributor.

The ‘second’ black wire mentioned in the previous post goes to a little round cylinder on the side of the coil, about the size of a d size battery. No idea what that is? In the picture I have shown this as a green line to make it easier to see.

But end result is the tach is working as it should and has no visual interference evident. Very pleased and thank you all again.

D battery cylinder connected to coil is condenser that WAS needed for conventional distributor but totally not needed with 123. Ok to take it out.

Would you mind helping me out to figure how to connect my 73 ES tach so it works?

[Grahamwhitfield]

If you can post pictures of what you have and how it’s connected I will see what I can do. I’m sure many others here would be able to help out also.

[25PSi]

Originally Posted by Grahamwhitfield

If you can post pictures of what you have and how it’s connected I will see what I can do. I’m sure many others here would be able to help out also.

FIGURED IT OUT WITH HELP OF GOOD "Internet" PEOPLE

am gonna try to return the favor and post best explanation i can.

Here is what stock setup on '73 1800ES looks like (On mine anyhow). RED to -; YELLOW(ish) to Distributor and BLACK that comes from another direction to +
https://ibb.co/tB2jgzh

And 2nd one is what it looked like after 123 install and Smith tachometer working.

Stock RED to -; Stock BLACK to +; RED from 123 to +; BLACK from 123 into the stock YELLOW(ish) wire that used to be connected to stock Distributor.
https://ibb.co/cJ0xPrL

Last one shows that YELLOW and WHITE wires from 123 go into stock plug that used to be plugged to the side of distributor.
https://ibb.co/qNdY0xs

[Grahamwhitfield]

Glad you got it working! Great diagrams too

[25PSi]

Just to point out: This is NOT how i will leave it. It will get cleaned up and "Bettered" Connections will be done properly using environment resistant connectors, long wires will be shortened, temp protective tubing will be used, suspended wires will be tied, etc

Just wanted to rush out those diagrams to have them out there.