Does any one have...??

[rclayton12]

Does anyone have a 3 wire tach. that they know for sure works?? I have a 1973 240z and cannot figure out what is wrong with my tach. I have the 3 wire it had on it, a 4 wire one, and a 280zx one, and none of them work. I get voltage from the plug under the dash, so I may just have 3 bad tachs. Is there a way to troubleshoot??

Thanks

[EScanlon]

Are you sure it's the tach that's bad?

How about the ignition wiring. Did you upgrade to the electronic dizzy? Are you using the E12-80 module? What about the original resistor? I've seen more tachs get replaced because the wiring was set up wrong after the electronic dizzy change than tachs that went bad.

Also, not sure why you would want the 3 wire, wasn't that in the 260 or the 280's?

E

[rclayton12]

The entire ignition is stock, factory coil, distributor etc... The car had all of the emission stuff the 260z had, so it does have the 3 wire connection. I hope to upgrade the ignition soon, but havn't yet. Do not know what the deal is with the tach. I can hook up a ohmmeter and get flutuation in current if i step on the gas while the car is on, that is why I think I may have bad tachs.. don't know though.