Tach. Stopped Working, Help.
Thread Starter
Intermediate
Joined: Apr 2004
Posts: 43
Likes: 0
From: bethlehem pa
Tach. Stopped Working, Help.
I just noticed that my tach. isn't working on my 76. When I turn the key off it moves to about 600 RPM and stays there. When the key is on or it is running it drops to zero and stays there. I believe the red wire plugged into the distibutor is the tach wire and that seems to be fine, in that the wire and plug are tight. Any ideas as to what is going on and how to fix it? How big a job is it to repair?
Racer
Joined: Aug 2005
Posts: 315
Likes: 0
I am also having Tach problems as it is.....the 2 most common problem is the tach filter(which connects to your distributor),or your printed circuit behind your tach needle.
I have just purchased a tach filter and am waiting for it to come in and try it out.
I will post my results when done
I have just purchased a tach filter and am waiting for it to come in and try it out.
I will post my results when done
Heel & Toe
Joined: Feb 2005
Posts: 18
Likes: 0
From: Port Macquarie New South Wales
Yeah, tachos are a problem. I've got a 79 and mine used to work on and off until recently when it went right up past the rev limit and stayed there - it moves about 1/8" when I turn the ignition on and off.
Don't want to hijack your thread but if anyone has any ideas about the problem I'd appreciate your thoughts. Thanks.
Don't want to hijack your thread but if anyone has any ideas about the problem I'd appreciate your thoughts. Thanks.
Le Mans Master
Joined: Jun 2002
Posts: 8,339
Likes: 24
From: I can walk to MA
Originally Posted by 76greenlar
I just noticed that my tach. isn't working on my 76. When I turn the key off it moves to about 600 RPM and stays there. When the key is on or it is running it drops to zero and stays there. I believe the red wire plugged into the distibutor is the tach wire and that seems to be fine, in that the wire and plug are tight. Any ideas as to what is going on and how to fix it? How big a job is it to repair?
Anyway, the coil cover on the HEI distributor has labels molded in the plastic.
Instructor
Joined: Aug 2005
Posts: 114
Likes: 0
From: St. George Ontario, Canada
Originally Posted by 76greenlar
Hijack all you want, I am looking for any suggestions and how to's. Trouble shooting electrical problems is not one of my strengths.
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Melting Slicks
Joined: Jun 2002
Posts: 2,609
Likes: 1
From: Behind the wheel of a large automobile
Originally Posted by Maymyvetteliveforevr
75 and up has electronic.
Pro
Joined: Apr 2005
Posts: 603
Likes: 2
From: Illinois, USA
Sounds very similar to the circumstances that I had. My tach would float around 600, but wouldn't go to zero at KO.
The circuit board is more often than not the culprit, although there are cheaper things to check first. You can bypass the filter and see if it makes a difference -- should be a go/no-go test. No change, it's probably the board.
I assume you've checked fuses and that apart from no tach, everything appears to work as normal.
Yes, brown is the tach signal wire.
I bought a replacement board, and I still had to go over every single solder joint before it worked -- while it was broke different, the new board didn't work when I got it. I purchased from Eckler's, but it was a Corvette America box.
Anytime you have to get at the tach, it always seems like a major PITA to disassemble enough to get at it, as I always had to take it out to get at the board.
Brian.
The circuit board is more often than not the culprit, although there are cheaper things to check first. You can bypass the filter and see if it makes a difference -- should be a go/no-go test. No change, it's probably the board.
I assume you've checked fuses and that apart from no tach, everything appears to work as normal.
Yes, brown is the tach signal wire.
I bought a replacement board, and I still had to go over every single solder joint before it worked -- while it was broke different, the new board didn't work when I got it. I purchased from Eckler's, but it was a Corvette America box.
Anytime you have to get at the tach, it always seems like a major PITA to disassemble enough to get at it, as I always had to take it out to get at the board.
Brian.
Team Owner
Joined: Apr 2001
Posts: 54,204
Likes: 180
From: S.W. Ohio. . . . . . NRA Life Member
Originally Posted by C3nMe
Sounds very similar to the circumstances that I had. My tach would float around 600, but wouldn't go to zero at KO.
The circuit board is more often than not the culprit, although there are cheaper things to check first. You can bypass the filter and see if it makes a difference -- should be a go/no-go test. No change, it's probably the board.
The circuit board is more often than not the culprit, although there are cheaper things to check first. You can bypass the filter and see if it makes a difference -- should be a go/no-go test. No change, it's probably the board.
I bought a replacement board, and I still had to go over every single solder joint before it worked -- while it was broke different, the new board didn't work when I got it. I purchased from Eckler's, but it was a Corvette America box.
Anytime you have to get at the tach, it always seems like a major PITA to disassemble enough to get at it, as I always had to take it out to get at the board.
Brian.
Anytime you have to get at the tach, it always seems like a major PITA to disassemble enough to get at it, as I always had to take it out to get at the board.
Brian.
the Gardner boards are top notch, well made, and are "pre-calibrated".
contact John Gardner via email:
jtandjudyg@aol.com
I convert 1968-1974 mechanical tachs to electronic use. I can also repair your 1975- 1977 electronic tach if needed; performing a full calibration (as the calibration from tach-to-tach varies a bit).
contact me via email if interested:
tim-yvonne@juno.com
Racer
Joined: Nov 2004
Posts: 319
Likes: 0
From: Sunnyvale CA
I had a similar problem except that sometimes the needle would jump around and sometimes it would work and sometimes it wouldn't do anything. I just bought a new plug for the distributer, soldered it up, and now it works good as new. just a thought.
Melting Slicks
Joined: Apr 1999
Posts: 2,010
Likes: 3
From: Moon Twp. PA USA
New tach board cleared up the problem. Installed without any additional work. From Doc Rebuild.
There was a slip enclosed with the board that said if you could not get the tach working, you could send the tach and the board to this person, and for a small amount of money, he would guarantee a working tach. Mine worked out of the box.
There was a slip enclosed with the board that said if you could not get the tach working, you could send the tach and the board to this person, and for a small amount of money, he would guarantee a working tach. Mine worked out of the box.
Team Owner
Joined: Apr 2001
Posts: 54,204
Likes: 180
From: S.W. Ohio. . . . . . NRA Life Member
Originally Posted by glen242
New tach board cleared up the problem. Installed without any additional work. From Doc Rebuild.
