HELP ! tachy not working
Thread Starter
Heel & Toe
Joined: Jan 2012
Posts: 17
Likes: 0
From: Toulouse France
HELP ! tachy not working
Hello everybody,
I changed the 73' cable tachy for an 77' electronic tachy. I have a problem with the connections at the back. We have 3 connectors in position like a letter L, the middle connector is the signal from the "Delco-Remy", the others 2 are the ground and the + 12 V.
My question is: where is connected the ground, where is connected the + 12 V in the tachy because we can reverse the 2 wires !! and burn the tachy.
Thank you.
I changed the 73' cable tachy for an 77' electronic tachy. I have a problem with the connections at the back. We have 3 connectors in position like a letter L, the middle connector is the signal from the "Delco-Remy", the others 2 are the ground and the + 12 V.
My question is: where is connected the ground, where is connected the + 12 V in the tachy because we can reverse the 2 wires !! and burn the tachy.
Thank you.
Thread Starter
Heel & Toe
Joined: Jan 2012
Posts: 17
Likes: 0
From: Toulouse France
Yes I have the control circuit board, I think you mean the electronic card fixed in the tach ? for the filter no I don't.
On the electric diagram we dont see any filter on the tach circuit where si it ?
Thanks
On the electric diagram we dont see any filter on the tach circuit where si it ?
Thanks
Thread Starter
Heel & Toe
Joined: Jan 2012
Posts: 17
Likes: 0
From: Toulouse France
OK I explain my problem:
I connect all to the tach (+12V, ground and the signal from distributor), when I turn the key, the needle goes to the 0 position that's OK but when I start the engine some smoke get out from the tach, I stop all immediately. I didnt insert any filter between the distributor and the tach.
Do you think that's the origin of start burning ?
I connect all to the tach (+12V, ground and the signal from distributor), when I turn the key, the needle goes to the 0 position that's OK but when I start the engine some smoke get out from the tach, I stop all immediately. I didnt insert any filter between the distributor and the tach.
Do you think that's the origin of start burning ?
Melting Slicks
Joined: Sep 2004
Posts: 3,225
Likes: 667
From: Northeast
I haven't had a tach filter in years, so doubt that not having one would make smoke.
You can see it here in the product illustration:
http://www.ecklerscorvette.com/corve...1975-1989.html
You can see it here in the product illustration:
http://www.ecklerscorvette.com/corve...1975-1989.html
Last edited by BKarol; Jan 10, 2012 at 08:23 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
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
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,852
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
If you hook power up to the wrong wire with a factory board you have blown the board... Here are the correct connections for the 1975-1977 tachometer. A new US made tach board is 58.00 http://willcoxcorvette.com/product_i...ducts_id=26840
And here is how to install a new board if you need one..
1975-1977
And here is how to install a new board if you need one..
1975-1977
Thread Starter
Heel & Toe
Joined: Jan 2012
Posts: 17
Likes: 0
From: Toulouse France
Thank you Willcox corvette, your pics are very helpfull for me, that's the response I was waiting.
But the electrical diagram in the Chevrolet chassis service manual 1977 is not showing the sames connections on the tacho connector.
I explain: the switched voltage and the tach are reversed. That's why I burned my tachometer.
But the electrical diagram in the Chevrolet chassis service manual 1977 is not showing the sames connections on the tacho connector.
I explain: the switched voltage and the tach are reversed. That's why I burned my tachometer.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,852
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
7t1vette... We had a customer recently that brought us a 71... It was wired backwards at the coil! That might explain why he wired it that way..
There is a orange wire that runs from the ignition switch to the fuse panel missing from the schematics on 1970-1975 schematics.. I've added it to all our schematics.. but what a pain. Nuts.. what one wire drawn wrong can do! Case and point.. the 68 schematic is by far the worst one every.
There is a orange wire that runs from the ignition switch to the fuse panel missing from the schematics on 1970-1975 schematics.. I've added it to all our schematics.. but what a pain. Nuts.. what one wire drawn wrong can do! Case and point.. the 68 schematic is by far the worst one every.
Last edited by Willcox Corvette; Jan 11, 2012 at 08:41 PM.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Another point of interest....
All of the schematics in the 1971 Chevrolet Chassis Service Manual (full-sized body and down) are correct on the way the coil is wired....except for the Corvette. The same draftsman probably did all of them. Makes you wonder---
All of the schematics in the 1971 Chevrolet Chassis Service Manual (full-sized body and down) are correct on the way the coil is wired....except for the Corvette. The same draftsman probably did all of them. Makes you wonder---
