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Bouncing Tach Needle

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DesertSprite

Jedi Warrior
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Hello,

The tachometer on my Sprite is possessed.

Just yesterday driving back home the tach needle would plunge down several hundred RPM's when I put the gas pedal down. This seemed to happen most in 4th gear around 3k rpms. After a second or two it would right itself and show the "proper" rpms.

Anyone have any ideas as to what may be going on here? Should I just start looking for loose wires or something else?

Thanks,
Joel

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At the risk of stating the obvious, start by examining all the wire connections. Bad ground and power connections can certainly cause that behavior. It could also be that something in the tach is failing. The tachometer has several capacitors and other components in it that fail with age. There are several articles on the net about how to rebuild/replace the electronics in old Smiths tachs.
 
I haven't had a chance to do anything with it yet. I know it most likely is going to be a bad wire connection. But, I thought I'd just put it out on the forum and see if there is some other common thing that fails in tachs.

Joel
 
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