HurstLightning84

Well I got another general question about my 84'. Since I'm in the process of fixing little things here and there, and since it's nice out and I have the ambition, my tach since I've owned I has read almost exactly double. Sometimes after I've ran it for a hour or so, or if it's really hot out and you flick the gauge lense, it'll start reading right?? Could this be a simple fix, or is this a huge headache that I should just leave alone.

ah64pilot

Leave it alone, shift at 11,000 RPM and tell EVERYONE about it! You have the only SBO in the World that sees over 8,000 RPM on a regular basis lmao!

Seriously, have you ever checked the wires on the back? Maybe one is loose? If not something obvious like that try hooking up a cheap tach to see if it's the car or the tach itself. Then you'll know how to go from there

ThePackRat

Common issue.

There's a lil' jumper clip (V6 vs V8) on the back of the tach that doesn't always play well.

Sometimes the clip can be removed & the metal part bent back to make better contact when re-installed.

I've done that in the past & had luck doing so.

Unfortunately ... that fix doesn't last long for most.

Most people end up soldering a small jumper wire over the back to the proper tach contacts.

Good news there is ... that pretty much fixes it permanently if done correctly.

The above fix is touched upon here :

http://tech.oldsgmail.com/ch_eint.php

And ...

http://tlentz.oldsgmail.com/howto.html