Tachometer problem

[pfouts1001]

'73 Chevy C30.  I bought the truck with a non working factory tach.  I believe the cab on this truck has been swapped.  After some investigation I found that the tach was not wired in completely.  I wired them as i thought they should go, and the tach will power up (needle resets to zero when the ignition is on), however will not register when the truck is running.  The tach has three wires; red, brown and black.  I currently have the red to power from the fuse block, brown the the tach terminal on the distributor and black to ground.  It just seems to not be getting any signal from the distributor.  Does anybody have any insight as to what i am doing wrong, or do i just have a bad tach?

73 C30 350/SM465 Dump
77 K10 350/350
02 2500HD 4X4 CC D/A

[roundedline]

It is very possible that the tach is bad, when they go bad they will bury immediately or not registet.

The wires are marked on the back of the guage on where they go though.  COIL, GND, 12V
Coil goes to the (-) side of the coil on the points and to the tach location on HEI
The other 2 are pretty self explanitory.

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

[pfouts1001]

Thanks for the confirmation rounded line..... I think the tach is bad, but will check the wiring one more time just to make sure.  Thanks again

[VileZambonie]

Maybe this can help but if the tach turn out to be the problem there's really nothing to rebuilding it!