Recalibrating 77 Tach
Thread Starter
Instructor
Joined: Nov 2006
Posts: 178
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From: Litchfield NH
Recalibrating 77 Tach
Is there a way to recalibrate the tach on the 77. I have all gages out and tach still reads 1800 RPMs. When it was in the car it would reset to 500RPMs with car idling. After I would shut it off it would read 1800 hmmm. Any ideas?
Team Owner
Joined: Aug 2006
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From: Columbia Missouri
May be a bad tach board, and it may be a bad filter at the distributor.
Race Director
Joined: Sep 2001
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From: Wellington, FL
St. Jude Donor '11 thru '25
These tachs will not read zero with the ignition off. My '76 shows around 700. Once the ignition is turned on, it should go to zero and, of course after starting the engine, it should show the proper RPM.
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
My '77 tach reads zero with the ignition off. It'll jump when I start it, but it's zeroed every other time.
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Well, I guess I've never seen one of these '75-'77 electronic tachs that zeroed out with the ignition off. Even the repair article I referred to above indicates one of the signs of trouble with these tachs is when they don't return to zero when the ignition is turned on. Anyway, I guess there's a first time for everything.
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Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Well, I guess I've never seen one of these '75-'77 electronic tachs that zeroed out with the ignition off. Even the repair article I referred to above indicates one of the signs of trouble with these tachs is when they don't return to zero when the ignition is turned on. Anyway, I guess there's a first time for everything.
Maybe mine's odd. Now, my red '77 had a tach needle that was usually near 4000 when it was off, but my blue '77 zeroed too.
Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
St. Jude Donor '11 thru '25
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
It'll be fine as soon as I make the spacer. I've tried wood, and they crack to easy. I tried a plastic cutting board, but it melts badly and any saw blade gets stuck. It would have taken forever. I'm looking for a new material now.
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
