67 Camaro Tach

Hi All,
I now have my car running thanks in part to all the exceptional help I got from this newsgroup.
When I parked my car 14 years ago the factory tach worked flawlessly. It
ran off of the points style distributor and coil. I now have an HEI system and the tach is inoperative. Is there a way to diagnose why it isn't working? Does anyone know about what type of signal the tach saw from the original ignition system?
I have access to an oscilloscope and a bit of electrical engineering background. I'm sure that if the problem is signal related that I could build a signal transformer circuit. I just don't know what the original signal looked like. Can anyone help?
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On Wed, 14 Jan 2004 21:40:59 GMT, "David R. McCoy"

If you have a G.M. HEI then you probably just need to hook up the tach wire point from the distributor cap to the corresponing wire on the tachometer inside the car. On the cap there should be 2 stamped abbreviated words one side "TACH" and the other "BATT". The "batt" goes to a 12vdc keyed switch and the other to your tachometer. The wire should be right where the old coil wires are.
...Ron -- 68' RS Camaro 88' Formula Bird
http://www.frontiernet.net/~rscamero
Some are wise and some are otherwise
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Hi Ron,
Thanks,
I have tried that already. The tach doesn't move. I assumed that the signal was different, maybe I shouldn't have. I'll do a bit more investigating (like making sure the bulkhead connector is making contact), and get back to the group if I'm still stuck.
Thanks
wrote:

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On Wed, 14 Jan 2004 21:40:59 GMT, "David R. McCoy"

I think some tachometers don't play nice with HEIs. Look at this page for starters:
http://www.holley.com/HiOctn/ProdLine/Products/IS/ISA/870-401.html -- lab~rat >:-) Do you want polite or do you want sincere?
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Thank you. I'll take a look and let the group know what I find out.
puked:

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