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: 3,223
Likes: 666
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.
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Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,850
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: 1,850
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: 3,114
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---
