tach question

[76bonanza]

My tach has stopped working I also just swapped my old hei for a new hei. But that was 2 weeks ago and the tach just quit today so not sure if they are related. I check all the wires they seem good. But I do not know what the signal wire should read mine reads like 13.68 and it is in constant change in that area I assume that is how it works? Anyone know what the signal wire should read?

Thanks

[hyarbour]

It would change with engine speed, even at idle there would be some fluctuation. Try setting you meter to read AC or Cycles (hetrz) would be even better. What might have happened is the connection in the HEI plug slipped while you were putting it in and finally lost contact.

[76bonanza]

But if I read voltage at the tach from the signal wire can I assume it is not the dizzy but the tach?

[hyarbour]

Most likely, that or the tach's ground came loose. Having a cheap tach for test purposes would be handy.