OH god if it is you have the wrong rotation on the distributor......wow.....does 1st gear go reverse??????? OMG
Tach runs backwards...
Thread Starter
5th Gear
Joined: May 2006
Posts: 5
Likes: 0
Tach runs backwards...
What would cause this? It runs very smooth, just backwards, its cool to say I shift my stock c3 at (whats the last number?? 7?) like 7K, more if I feel like it, but its weird at the same time...
Any fixes, or just replace?
Any fixes, or just replace?
Safety Car
Joined: Dec 2005
Posts: 3,782
Likes: 0
From: Some Beautiful Place Sunny and Amazing One
Originally Posted by Jefftopgun
What would cause this? It runs very smooth, just backwards, its cool to say I shift my stock c3 at (whats the last number?? 7?) like 7K, more if I feel like it, but its weird at the same time...
Any fixes, or just replace?
Any fixes, or just replace?
but if it really happens to you, check if you have inverse wires installation (+ wire connected where should be a - wire connected and viceversa).For an igniition system with breaker points check the following:
1. The - wire of the ignition coil must run to the distributor points.
2. The + wire of the ignition coil must be installed to one connection of the ignition switch.
3. The other connection of the ignition switch should run to the solenoid connection that also have connected a black wire that run to the + terminal of the battery.
4. The coil wire run (center wire from distributor cap) should run from distributor to center connection of the coil.
5. A second wire, also a + wire of the ignition coil should run to the oppose connection of solenoid described in item 3.
6. Check starter and battery grounds.
Last edited by c3dreamer; May 15, 2006 at 10:02 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Originally Posted by HDFLH67
I have a '75 that does the same thing. No one here has been able to come up with a serious suggestion yet, and I have been asking for ages. If you get it fixed, I'd love to know what you found!!!
Thats about the only thing I can think of
This is a very strange problem and the first Ive ever heard of
Le Mans Master
Joined: Nov 2003
Posts: 5,772
Likes: 694
From: Maryland
St. Jude Donor '05, '09, '15
Originally Posted by Jefftopgun
What would cause this? It runs very smooth, just backwards, its cool to say I shift my stock c3 at (whats the last number?? 7?) like 7K, more if I feel like it, but its weird at the same time...
Any fixes, or just replace?
Any fixes, or just replace?
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Originally Posted by Sky65
Never heard of that one before. Is the tach electronic or mechanical, stock or aftermarket, did it ever work correctly? Where does the needle sit with the engine off, zero or maxed out?
Thats a beautiful 65
Drifting
Joined: Nov 2003
Posts: 1,634
Likes: 4
From: Northern NJ
St. Jude Donor '04 & '05
Originally Posted by HDFLH67
I have a '75 that does the same thing. No one here has been able to come up with a serious suggestion yet, and I have been asking for ages. If you get it fixed, I'd love to know what you found!!!
Good Luck!
Melting Slicks
Joined: Mar 2006
Posts: 3,456
Likes: 102
From: Piedmont Va
St. Jude Donor '11-'12-'13,'19-'20
Per the Corvette black book, 1975 was the first year for HEI and electronic tac. My guess is that the TAC signal and ground wires are inverted.
Last edited by CheezMoe; Jul 2, 2006 at 09:19 PM.
Drifting
Joined: Nov 2003
Posts: 1,634
Likes: 4
From: Northern NJ
St. Jude Donor '04 & '05
Originally Posted by dosoctaves
..... My guess is that the TAC signal and ground wires are inverted.
If the tach is moving backwards then either the circuit board or the tach movement has an issue. The movement itself is capable is turning nearly 360 degrees, but normally the signal driving it wouldn't do so. The fact that it is points toward an issue with the board itself.
You can get a replacement board for $60-75, but often these don't work as well as they could. Another option is to have the original board repaired. That can usually be accomplished for about half this cost.
Hope this helps. Good Luck!
Last edited by ACECO; Jul 3, 2006 at 10:57 AM.
