Topic: 1977 Tach Problem
in Forum: C3 Electrical
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I have a 77 Vette and when I shut off the car the tach is at 6,000, when I start the car it buries itself past 7,000. HELP!
Thank you in advance.
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Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
What'er ya gonna do? You can't hold back a 'Vette when it wanna go!! 
Sounds like the printed circuit board(on the back of the tach) is damaged. Did this just happen all of a sudden, or has there been some fluctuating of the tach for a while? Disconnect the "tach" wire from the dist. and see if the tach goes to "0" with the key on.
If disconnecting the tach wire does not change anything, then the problem will be in the tach, or the circuit board.(possibly a ground prob., but that would normally effect the other gauges, also)
If it does correct the problem, then you need to replace the ign. module, most likely.
btw....I see that your '77 has a white int. Is it all white, or does it have a "two tone"? The two tones are very rare!!Adams' Apple 38566.8216898148
Sounds like the printed circuit board(on the back of the tach) is damaged. Did this just happen all of a sudden, or has there been some fluctuating of the tach for a while? Disconnect the "tach" wire from the dist. and see if the tach goes to "0" with the key on.
If disconnecting the tach wire does not change anything, then the problem will be in the tach, or the circuit board.(possibly a ground prob., but that would normally effect the other gauges, also)
If it does correct the problem, then you need to replace the ign. module, most likely.
btw....I see that your '77 has a white int. Is it all white, or does it have a "two tone"? The two tones are very rare!!
Joel Adams
C3VR Lifetime Member #56 
My Link 
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Thank you for replying. The problem occurred all at once, no indication of a problem going to happen.
The interior is indigo blue and white.
in Forum: C3 Electrical
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