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Inaccurate Tachometer. Board?

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Old Mar 14, 2022 | 03:43 PM
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Default Inaccurate Tachometer. Board?

My factory tachometer in my 1980 Corvette is not accurate. It doesn't bounce around, but it does want to jiggle or jump up/down slightly at idle at times. It does reset to 0 at key-on (and will rest at ~2,000 key off), but the accuracy degrades as the revs increase. For example, at a 65 mph cruising speed, my Holley Sniper screen will read ~2600 RPM (3.08:1 rear gear, 4-speed transmission), but the factory tach will read high, at around 2900-3000 RPM. The sniper and the factory tach are pulling their signal from the same source on the distributor. My sniper and digital timing light both confirm that my factory tach reads high, and the percentage that it reads high increases as the revs increase. Is this a sign of a bad or failing tach circuit board, a faulty tach filter, or maybe both? To my knowledge, the tach board is original to the car.
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Old Mar 14, 2022 | 03:47 PM
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Originally Posted by Z0Tex
My factory tachometer in my 1980 Corvette is not accurate. It doesn't bounce around, but it does want to jiggle or jump up/down slightly at idle at times. It does reset to 0 at key-on (and will rest at ~2,000 key off), but the accuracy degrades as the revs increase. For example, at a 65 mph cruising speed, my Holley Sniper screen will read ~2600 RPM (3.08:1 rear gear, 4-speed transmission), but the factory tach will read high, at around 2900-3000 RPM. The sniper and the factory tach are pulling their signal from the same source on the distributor. My sniper and digital timing light both confirm that my factory tach reads high, and the percentage that it reads high increases as the revs increase. Is this a sign of a bad or failing tach circuit board, a faulty tach filter, or maybe both? To my knowledge, the tach board is original to the car.
here you go.. skip to the end if suspense killing you
https://www.corvetteforum.com/forums...-question.html
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Old Oct 26, 2022 | 05:51 PM
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From: South Hadley Massachuettes
Default Question Please ?

I know AC Delco no longer makes Tachometer's, ,

Who is "K&B" ?

Does "K&B" make Corvette Tachometers ?

Is "K&B" a replacement reproduction company that makes Tachometer's
(not lisenced by GM correct)
Sincerely, Dee
1980 Corvette • auto • blue/blue cloth • blue mirrored tops • 99.9% original (no A.I.R.system • no Cat • removed all that crap yrs ago)
L-82
Gymkhana Suspension
.

. 🇺🇲✌😉✌🇺🇲
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