C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

81 tachometer

Thread Tools
 
Search this Thread
 
Old Dec 2, 2015 | 07:52 PM
  #1  
81skyblue's Avatar
81skyblue
Thread Starter
4th Gear
Supporting Lifetime
 
Joined: Dec 2015
Posts: 4
Likes: 0
Default 81 tachometer

Recently purchased an 81 corvette that was in good condition before being submerged in water during a recent flood. I was given a price I couldn't refuse. We now have it running a running quite well.

We are working on the tachometer. We have located the wire underneath the distributor cap but can not find anything to plug it in to. Any help would be appreciated
Reply
Old Dec 2, 2015 | 08:53 PM
  #2  
toobroketoretire's Avatar
toobroketoretire
Melting Slicks
 
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
Default

Originally Posted by 81skyblue
Recently purchased an 81 corvette that was in good condition before being submerged in water during a recent flood. I was given a price I couldn't refuse. We now have it running a running quite well.

We are working on the tachometer. We have located the wire underneath the distributor cap but can not find anything to plug it in to. Any help would be appreciated

The tachometer wire plugs into the underside of the distributor cap where its marked "TACH".
Reply
Old Dec 2, 2015 | 09:48 PM
  #3  
Willcox Corvette's Avatar
0Willcox Corvette
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
Default

Toobroke is right.. here is a picture
Reply
Old Dec 3, 2015 | 05:26 PM
  #4  
81skyblue's Avatar
81skyblue
Thread Starter
4th Gear
Supporting Lifetime
 
Joined: Dec 2015
Posts: 4
Likes: 0
Default



It seems as though the wire is plugged in to Tach like it should be. What is the "extra" white wire?
Reply
Old Dec 3, 2015 | 07:22 PM
  #5  
havesometo's Avatar
havesometo
Drifting
10 Year Member
 
Joined: Dec 2012
Posts: 1,360
Likes: 59
From: Meldrim Georgia
Default

I'm not positive but I think it's a factory test terminal.
Reply
Old Dec 3, 2015 | 07:49 PM
  #6  
Willcox Corvette's Avatar
0Willcox Corvette
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
Default

Originally Posted by havesometo
I'm not positive but I think it's a factory test terminal.


Indeed.. the extra plug is for testing.

-Willcox
Reply
Old Dec 4, 2015 | 12:26 AM
  #7  
81skyblue's Avatar
81skyblue
Thread Starter
4th Gear
Supporting Lifetime
 
Joined: Dec 2015
Posts: 4
Likes: 0
Default

Originally Posted by Willcox Corvette


Indeed.. the extra plug is for testing.

-Willcox


Thanks. Tachometer is stuck on 20. Attempted to bypass the tach filter but no change. Using a test light, the wire is hot. Not sure where to go from here
Reply
Old Dec 5, 2015 | 02:17 PM
  #8  
Willcox Corvette's Avatar
0Willcox Corvette
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
Default

If you bypassed the filter and you still don't have a working tach, you probably have a board issue on the tach...

So.. I'd pull the tach out of the car... (it's easy) by removing the lens (5 screws), and then the gauge inner bezel which is six Allen head screws. Once you remove this bezel then remove the three tach retaining screws and the tack will pull out of the housing.

Once you get this far, with the key on test the power clip for voltage using the ground clip as your ground. If you don't have voltage showing on the power clip, then use a different ground and test again (it may be a ground issue and this will eliminate that possibility.

If you have power and ground then test the signal clip for continuity from the clip to the plug where it plugs into the tach filter. If you have continuity then you need a board for the tach. If you don't have continuity then you need to find the break in that wire.

Here are so pages from my website that will help you.
1978-1982 Corvette Tachometer Testing, Removal, Board Installation
Reply

Get notified of new replies

To 81 tachometer

Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-1

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-2

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-3

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-4

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-5

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-6

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-7

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
story-8

2027 Corvette vs The World: Every C8 vs Its Closest Competitor

 Joe Kucinski
story-9

10 Most Common Corvette Problems of the Last 20 Years!

 Joe Kucinski




All times are GMT -4. The time now is 07:33 PM.

story-0
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-1
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-2
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-3
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-4
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-5
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-6
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-7
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE
story-8
2027 Corvette vs The World: Every C8 vs Its Closest Competitor

Slideshow: 2027 Corvette lineup vs the world.

By Joe Kucinski | 2026-04-24 16:12:42


VIEW MORE
story-9
10 Most Common Corvette Problems of the Last 20 Years!

Slideshow: 10 major Corvette problems from the last 20 years.

By Joe Kucinski | 2026-04-14 16:37:05


VIEW MORE