Sporadic Tach

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Jul 23, 2009 | 12:58 PM

Jordan901

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Sporadic Tach

My 81' F150 has a stock tach, and it likes to be fickle. It works, then doesn't work, then works, and so on and so forth. There is no noticable condition that make it work or not, it will just all of a sudden jump back up and work again, or will all of a sudden quit, often many times in a short drive.

I have re-soldered all connections, opened up the tack itself, tried everything I can think of, no luck. Thoughts?

Jul 23, 2009 | 08:09 PM

ctubutis

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From: Denver Metro Area, CO

https://www.ford-trucks.com/forums/8...-sticking.html
https://www.ford-trucks.com/forums/8...ter-cured.html

Jul 24, 2009 | 06:14 PM

hydmech

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From: Washington state

I have the same problem. Those links are really good info. Guess Ill be opening up the dash this weekend.

Jul 25, 2009 | 02:32 AM

Sycostang67

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Joined: Dec 2002

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From: Kuna ID

I had the same problem with 2 tachs. Removing the glue fixed one of them and helped the other a bit. It's still kind of fickle though, just not as often.

Jul 26, 2009 | 02:38 AM

Jordan901

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Thanks for the help, will try that. Makes sense.

On a slightly different note, what is the wiring scheme for the 1981 stock tach? It has 4 wires I believe, where do they go? I've replaced the coil and distributor with an MSD system, it's a ready-to-run distributor that eliminates the ignition module. So now that the module is gone, what should the tach be re-wired to?