Sun Tach Problem

[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.

[72-SS-L48]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: njsteve</div><div class="ubbcode-body">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. </div></div>

That's a great suggestion. Thanks Steve.

Tonight I'll play around with it and see what happens.

-Dave

If my feeble old memory serves me correctly, the fuse box wire should be for the tach light only....so it should be clipped into that particular circuit.

Wayne

[VintageMusclecar]

Just noticed you said the tach has 3 wires--shouldn't there be 4?

If memory serves, there should be a black for ground, a white for light, a green that goes to the coil, and a red for power.

[72-SS-L48]

The wires are as follows.

Black that goes grounds to a metal support under the dash
Red that clips into the fuse box (power)
Green that goes to the coil
And the light wire that also clips into the fuse box (mind you the light does work, even with the tach not working)

Thanks,
Dave

[mockingbird812]

Which side of the coil are you tapping into?

[72-SS-L48]

The Green wire from the tach is going to the negative on the coil. I hit my power probe on the red wire from the fuse box and it has 11.6 volts.

Thoughts?

Dave

[72-SS-L48]

All connections are new and look good. I didn't replace any. How do you test the green wire from the coil? I know the coil is good since the car starts.

-Dave

[Plowman]

A quick way to check the green wire is with a test light and tapping the engine over a time or two. Test light should go on and off[not runing]. Not all coils are good since the car starts,some bad coils run out of spark and give a feeling like running out of gas. Could try another known good coil. The green wire should be on the negative side of the coil witch is also the distributor side. Hope this helps. Paul