Tach wont work

[1981 ss chevy]

I just installed a new tach in my truck i had old wiring from my old tach and i tried the tach first to make sure it worked.  It does.  So i decided to rewire the whole works, ground, hot lead, disty line, and one to the lights.  Now once i got done wiring it it wont register anything while truck is runing only it lights up.  I have a good ground and a good hot line its wired in with the ignition.  I thought maybe it was my disty cab so i put on a new one still nothing.  So i went through my wiring again its all good to go but still no luck. I dont kno what else to do you guys have any ideas??

[Armor]

i dont know the brand you have, but one i had(sunpro) once had the tach wire disconnected from the board inside the gauge, as if it was pulled hard and broken, dont know if it applies but just a thought

[VileZambonie]

You hooked up to the negative side of the coil right?

[1981 ss chevy]

no i have it grounded inside my cab its always worked this way

[howlinwolf]

i think he meant the signal wire, but if its an 81 the coil is on the distributer cap right?

[1981 ss chevy]

correct the disty has a lil tach outlet and today i went to put gas in and it worked right when i started it and then as i was driving it just all at once quit working so i jiggled all the wires still nothing

[VileZambonie]

Check your connections

[1981 ss chevy]

i did they are all tight and right still nothing is it possible for a wire to be bad or burnt?

[howlinwolf]

its possible that the wire has a short, or the tach has a short. is it new or reused from something else. (i ask because ive had my tach on 3 vehicles.)

[1981 ss chevy]

ya i've had this tach in two trucks and a monte, but i figured it out my hot lead wire was bad i tried using new wire and now it works like a champ