cb98coupe

So , I finally dialed in my cold idle speed . Took me a few tries but now it is perfect .

When I shut the car off the tach needle pinned itself at 7000 rpm and isn't moving anymore .

Any ideas out there ? I am guessing this is a common issue . Thanks in advance ...

softwarejanitor

It is a common problem. Most of the time when this happens it is the circuit board on the back of the tach that blows out. You can buy a replacement from Wilcox, etc. Cost is around $60.

https://willcoxcorvette.com/corvette...80-82-usa-made

Shark Racer

I used to have a problem w/ the tach spiking when I shut the motor off - particularly prevalent if I did this while the RPMs were up. This would cause the tach to bounce "over center" and come to rest at 7k. I'd have to get the RPM up a bit and once it hit an area near center it would spring back to functioning. Worth a try if you haven't done this yet.

cb98coupe

Thanks everyone . I will try the latter and if that doesn't work I will get the board . I looked up a thread and it looks like the board is easy to change . Willcox seems to be very helpful also when it comes to these things .

It's pretty funny , I got the car about a month ago and the tach would be a little jumpy at times .

I am hoping I can get it to reset by bringing the revs up like suggested .

Thanks for the replys , keep em comin ...

cb98coupe

Come to think of it , this is exactly what happened . I gave it a good gun right before I shut it off and it got pinned .

I am hoping to start it up after work and give it a good rev to see if it comes back to life ... Thanks ...

C3 4ME

Mine pins at 7k all the time. As soon as I drive a little it starts functioning as normal, and works fine while driving.

cb98coupe

Seems like the news is looking better for me as the day goes by . I can't wait to give it a whirl tonight .

Problem is my drivers seat bottom is being reupholstered and I really cant drive her around much .

Maybe a good rev will get er up and running again ...

Sluefoot

If yer gonna get a new circuit board 4 yer tach, I'd spend a little more & get a new filter at the same time....I changed both a couple months ago, as it was stuck on 4500 from the time I bought it in Jan. this year...been workin' GREAT since...got from Wilcox.

cb98coupe

So , I got home tonight , had my dinner and went out and gave it a whirl .

I started the car and let it sit at cold idle for about a minute and kicked it down . Once I kicked it down I gave it a few revs and the tach came back around .

So , looks like you have to shut the car down without revving it or it will get pinned .

What I do notice is the tach can be shaky at times . Sometimes I will start it and it is smooth as silk and then other times it will work but very erratically .

I am going to take everyones advice and get the new circuit board . I just got the car about a month ago and I have been fixing a few cosmetic things . The passenger t top was broken during transport so I couldn't really drive the car until I got a new set .

I am picking up my drivers seat on saturday after a refurbishing of the lower cover , then I am going to get the car out and run it for a while . It needs a good drive to blow out some of the cob webs .... I can't wait ....

Thanks for all the help ...

Shark Racer

How shaky is shaky? My tach is shaky when the car is idling cold. It stabilizes as it warms up.

The shakiness of the tach correlates to obvious engine behavior, though.

cb98coupe

It's a little wild but mostly when cold . The motor was professionally rebuilt to a 383 stroker about 15 years ago so it's got a rumble .

I am going to keep an eye on it and see how it behaves . thanks ...