Sun Tach Problem

[72-SS-L48]

Hi Guys,

The Sun tach in the 69 Z was not accurate so I pulled it out today. Since I did not want the tach wires to dangle, I installed another Sun Tach I had. It's the same model number and NOS perfect. It did not work in the car. I swapped that one for another and that didn't work either. Finally, I put the original tach that I removed back in it to see if that worked. NOTHING! What did I do? What happened that no Sun Tachs will work? I did not alter the wiring.

Thanks,
Dave

[VintageMusclecar]

Are these tachs stand-alone units or do they use transmitter boxes?

[72-SS-L48]

None require senders.

Thanks,
Dave

[VintageMusclecar]

How do you have the tach wired?

[Plowman]

That I think is a points tach. If a elt ign,or MSD,you will need a part on the white wire. Hope that helps. Check points and condenser too. Paul

[72-SS-L48]

The car has its original ignition system. The tach is wired with three wires.

One wire as the ground, one going to the coil and one plugging into the fuse box.

Mind you the tach worked when I pulled the car out of the garage, I went to swap tachs and nothing!

-Dave

[VintageMusclecar]

Start with the basics--check the wires for breaks and make sure you're still getting power to the tach from the fuse box.

[72-SS-L48]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: VintageMusclecar</div><div class="ubbcode-body">Start with the basics--check the wires for breaks and make sure you're still getting power to the tach from the fuse box. </div></div>

Didn't see any breaks. Wires look good (brand new). I'll hook a test light up to the wire from the fuse box tonight and see what happens. Should there be power from the fuse box at all times (with the battery connected) or does it need to be in the &quot;on&quot; position or car running?

Thanks Eric!

Dave

[VintageMusclecar]

Key on (ignition) only.

[njsteve]

Sounds like the wire broke at a terminal. Cut all the terminals off and install new ones. A lot of times the wire will break but the insulation will still hold it in place in the crimped-on terminal, making it look like a good connection.