The tachometer on my 82 vette is stuck on 40 - is there an easy fix for that?
This happened while i was driving it - i noticed it stopped moving and now is stuck there - even when the car is not running!

 

Check the electrical connection at the distributor. The tach is half of the connection.

 

My tach is also stuck at 35. Be interested in hearing a solution. The wire to the dizzy is OK.

 

Mine is stuck at 20,

 

ok - i will give that a try - thanks!

 

I had this problem. My tach stopped working and I replaced the Tachometer filter. Willcox sells it under part #618561F but you can find them on E-bay for half that price off a used car.

 

Thanks - I will order one asap!

 

We’ll I love selling parts, but you can test the filter before you move forward.

The filter should have an ohms reading from end to end round 500 – 590. Anything in this range will be fine.

What is easy to check is the input to the tach. If you remove the tach speedo lens from the car by taking the screws holding the lens. Then remove the three screws holding the tach in place. You can then pull the tach out of the car. Yes, you can pull it straight out!

Once the tach is out of the dash you’ll see three silver clips in the housing.

You can test each of these clips to check for Voltage, Verified ground and that is it. The lower clip is the input signal to the tach. The right hand clip is the power supply to the tach and the left hand clip is the ground.

If you have power and ground at these two points the odds are that the tach board is defective in the tach. A working tach with power and ground should go immediately to zero and be waiting for input signal. A tach that is turned off while running will usually hold the last reading until energized again. (Key turned on).

If you do not have power or a good ground to either clip you’ll need to pull the cluster out and find out why.

At this time you can also verify continuity of the wire from the tach to the distributor by testing it on the lower clip to the end of the wire before it plugs in to the tach filter.

We have good USA made and tested boards in stock. Each and every board we have is tested for accuracy before it is sent out.

You can search our tech site at this link by entering the year of the car in the left box and then searching the word TACH. http://repairs.willcoxcorvette.com/

Willcox

 

Before you start replacing parts, you might identify the part that is bad. I replaced my tach filter, circuit board three times and it wasn't until I installed another tach that it worked again. A forum member sold me a tach with original circuit board from a parts car for $30. Good luck...finding a cure isn't always easy. Replacing the wrong parts can get costly.

 

This is starting to get comlpicated. On the tach filter assembly, I noticed that one connector is not connected to anything - is this a test connector? If not, should it be connected to somehing? Where?

 

Yes this was a service port and Red is 100 percent correct!

It's to easy to test to replace things without knowing.

With the info I gave you above remove the tach and see if you have power and ground. If you do have this on the two clips then the tach should go straigth to zero when you turn on the key.

Always remember, none of them actually sit right on zero but it should be close.

If you have power and ground and the tach is not going to zero, you have found your problem is in the tach.

If the problem is the board or in the movement area is a hard thing to tell without the correct testing equipment. More times than not it is the board, however we did have a customers tach in the shop the other day that did have a bad movement.

Willcox Inc.

 

If the connector you are referring to is coming out of the firewall and white, it might be the wire coming from the tach and connects to one side of the tach filter. The filter is a silver cylinderical thingy bolted to the intake manifold on the drivers side. The other end of the filter clips to the distributor cap, next to the battery wire for the coil.

If you remove your tach, it is fairly straight forward, just be careful not to overtighten the lens screws and crack it on install. The tach will come out by pulling it straight out. There are three screws on the back that just push in for a mount connection. Handle it carefully. Look at the cuircuit board on the back for a burnt spot. If one is seen, that is a good indicator the board is bad. Try to identify the problem before simply replacing parts.