tach not working

[nicolas]

on both my points distributor and the one with a module the engine dies as soon as i connect the tach. it doesn't even start if it is connected when i start.

i found this very strange, i never had the problem before, but the tach did bounce a bit up when it should read a stable rpm. so i suspected bad ground, but with and tester i had the lamp turn on. i am a bit puzzled and i am overlooking the obvious here for sure.

[JezWest]

Weird. The tach lead should be just a measuring point, but it sounds like it's either grounding the input to the points or holding it at 12v. You're connecting the tach to the distributor side of the coil? You're connecting the 'sender' wire, not the wire for the illumination? Be careful though - the coil isn't usually fuse protected so if something has failed you could get alot of current flowing through the tach or points. Keep a nose out for hot wire insulation - I torched my points wiring whilst setting the timing in the past 

[TexasTom]

Be sure that all tach wires are connected to proper position.
I had a  customer with same problem ... his power & ground for tach were reversed.
Had another gut that had all of the coil connections reversed! Positive coil to #1 and negative coil to #15 ... still ran fine, but nothing with tach wire connected.
TxT