Sun Tach Problem

[72-SS-L48]

The green wire makes the connectivity test light up when I tip the key. Still no tach works...

-Dave

[Plowman]

The test light should go on and off[not runing]. The tach works off distribtor pulses. Make sure it is on and off test light at distribtor wire[not runing]. Paul

[SuperNovaSS]

How are you hooking it up? Red: 12v switched power, white: light, black: ground, green: Neg. Side of coil?

Jason

[SuperNovaSS]

Oops, missed a page. I would bench test the tach and go from there.


Jason

[72-SS-L48]

Guys,

I hooked up one of my 8k tachs to bench test it. The tach does not work. It looks like I will send that one and my 10k back to D and M Restorations and see what they say. It's under warranty, I just do not know what caused them to fail...

Thanks,
Dave

[njsteve]

Have you checked the running voltage and the cranking voltage at the coil neg terminal? When i had the defective wiring harness that was missing the resistor wire, it put out way too much voltage when running and burned out the factory tachometer (14 volts when running). There should be 12 volts when cranking and 9 volts when running.

Make sure you're not just chasing a symptom instead of fixing the problem.

[SuperNovaSS]

The strange thing is you had a working tach that is now not working. It sounds like lines got crossed somewhere and all the tachs were fried as a result.


Jason

[72-SS-L48]

Guys,

I installed my last NOS unit in the Camaro. This one worked like a charm. I'm thinking my other NOS unit flat out does not work and maybe in swapping the two rebuild units two wires touched? I still do not understand how this happened since the battery was disconnected during the swaps but anyhow...

The rebuilt tachs have warranty's so they will be working in no time.

I appreciate everyone's help!

Dave

[Salvatore]

Trial and error. Its what makes this hobby fun or I should say rewarding.