[johannes]

So.... I had my wife pull the coil out of her chally in December,...as I needed it in a Chebby...
I put it back today,...but I was in a bit of a hurry,...so I forgot to connect the negative side of the coil,. to the points...thus only + and Tach(-) was connected....
Obviously the car didn't start.....
After som head scratching, I found out...connected the (-) also,...the car runs great,..but now tach don't work....
Any suggestions as to what happened,...and how to remedy the situation ?


Also,...why why why, when I type,... all of a sudden the cursor jups the middle of else somewhere to ????

[dave-r]

To put it simple. When you cranked the engine you basically connected the tach across the battery.

When cranking you have full battery voltage across the coil.

The -ve of the coil earths through the points. Without the points in circuit you earthed the coil through the tach.

So I am guessing the tach burnt out.

[johannes]

Grrr.
I good sunligth, I found that what I thougth was the tach cable,...was the cable I used for running a shiftligth..some years ago.....
I connected the cable for the tach,..and now it works....

Some more details on the tach signal.
On the Baracuda, (The other car...)...I'm running a Tach adapter.
The GearVendor Auto Shift Sequencer needs the tach signal,...so I borrowed it from under the dash....
I was surprised to "feel" the voltage going in to the tach......I was expecting 12V,...but surely I wold not be ble to feel a small el-shock from only 12 V?
I felt the shock when I put the ignition "ON"...
Just for info; The tach on the Barracuda is working,...but I'm yet to test the ASS.

[dave-r]

That was a bit of luck.

Yeah you can feel 12 volts as long as you can get it to flow. It will put 100 amps into you if you were a strong enough dead short.

Actually. Might it have been a bit of back emf from the coil somehow?