[prexford]

My original 71 tach stopped working. Bought OER and it will not work. Sent old tach to get rebuilt with new electronic board versus mechanical and it will not work. Us inning Pertronix ignitor 2. What do I need to get to fix this? Filter?

[70RAlll]

Does your tach connection on rear of gauge cluster have 1 or 2 spade connectors? Should only have a single, if it has 2 you will need to connect a ground wire to the 2nd spade. You can just run a ground to the metal under dash . If it has the single spade(which 71 should have) make sure your tach lead wire is connected to the side of the coil that has the "-" and make sure the inline fuse on the tach lead is good. since you seem to be having trouble with OER and original tach I think it has to do with your single vs 2 spade connection. The OER,last time I checked, was a 72/3 up style with the 2 spade connection, 1970 and 71 had the single spade. I bet you just need to add the groud wire to the back of the cluster.. good luck..

[Held for Ransom]

The original tachs had a ground built into the case. The older tachs had a spade for the coil. The '72-up tachs had a separate power source spade and a spade for the coil. Not sure what OER has.

[prexford]

2 connections:, one to coil neg other to 12v, and tach is grounded.

[Norwood]

I have run both Pertronix 1 and 2 with normal tach hookup as described by 70RAlll with good results.

[78w72]

does it have an inline fuse in the coil wire or power wire?

[Norwood]

Originally Posted by Norwood

I have run both Pertronix 1 and 2 with normal tach hookup as described by 70RAlll with good results.

I only made this statement to show that the tachs are compatable with the pertronix ignition.

[Held for Ransom]

So what you're saying is maybe an extra ground wire from the tach body to a good ground source fixes the problem?

[Norwood]

I do not have a separate ground on mine. Just the normal single wire from tach to - coil


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[Held for Ransom]

Ok, so you were speaking of your original unit, not OER.

prexford, were you working on anything under the dash or hood when you noticed the original unit stopped working?

[prexford]

I did nothing else under the hood or dash when the tach stopped working. My old original tach worked with pertronix, for 10 years. Then one night it started bouncing around. I instLled an OER tach and it worked for 30 days, then it stopped working. Bought a new OER tach and it is not working and got my old one restored and it's not working.

[Held for Ransom]

Have you tried grounding the case of the tach with a piece of wire to a different ground (not using the printed circuit)?

[SD73]

I'd say at this point pull out the old volt meter and check the connector to see if it's getting power. Once you've ruled that out then you'll know you're troubleshooting the right side of the connector.

[Norwood]

I would take the tach out of the pod and hook it direct to the coil and ground to see if it works. If it dosen't the tach is bad if it works the wiring is bad. Simple

[prexford]

Good test. But I've done that. I read on forums the pertronix has a differ signal and a tach adapter or filter is or may be required?

[SD73]

I use the Pertronix II. My tach reads a little lower than it should. I tried using the filter as suggested and it made no difference. If you aren't getting any movement, that doesn't sound like your issue either.

[prexford]

I can get the needle to register on both tachs..little movement to zero from start up, but nothing more. I got 2 tachs, both are doing the same thing.

[SD73]

So you hooked your tach directly to your coil and get minimal movement? If you're sure the wires going to the coil are correct and you're tach wire is on the correct terminal you could try ruling out the coil and pertronix next.

If you have another coil you could swap in, that would help verify the coil isn't causing the issue. It's a long shot if your car runs. I'm using the Flame Thrower coil and not the stock one but either of those should work.

If the coil swap doesn't do anything you could try to put your points back in just to be sure your tach's is not damaged. And also worth noting, but should not affect your tach is that your coil should be getting full power at key on. Not the power that comes supplied from the factory wiring. You should be running power to the coil from a key on source from your fuse block. Again, I don't think that would cause this problem, but it certainly will help your Pertronix run properly.