for some reason or another when i got the car the tach was kind of funny and floated around wherever it pleased and when the ignition was off it would sit around five hundred rpm
but now my tach doesnt work at all
im wondering if its just just gummed up and needs to be replaced or is it a wiring problem
i tested for a connection between the wire in the engine bay that runs through the the condenser like cylinder. and it didnt have a full connection.

78 camaro z28 350
4 speed

 

there should be a hot lead to the tach then the signal comes from the negative side of the coil. Sick