So my car finally started, and for some reason or another, my tech is always at 7000 rpm, it moves forward after I rev it but never goes back down, and obviously my idle isn't that high. Any Ideas?

 

Try disconnecting your alternator and starting it up. It might be your volt gauge.

 

+1

 

You're probably (hopefully) not revving past 7000 all that often, either.

Does it go to zero with the key off? (If no, mechanically bugged tach)

Does it show proper battery voltage with the key on but the engine not running? (If no, electrical flaw somewhere)

If you disconnect the tach sense lead with the engine running (a plug-on connection at the lead coil - terminal) does it drop to zero, or does it stay up? (If stays up, likely a short somewhere)

Are your fuel and temp guages working OK? If not, could be a fault in the small voltage regulator on the back of the guage set. (Unlikely but possible)

Check your charging voltage with the engine running; could be your main voltage regulator is running too hot (high voltage), not allowing the tach to properly sense true RPM.

And as always, verify your grounds are good, particularly the one that grounds the instrument panel - - the ever popular X-15, up under the dash.

The tach circuit on 79's and 80's is really simple; it's basically a slow-response voltage guage connected to the negative side of the leading coil.

 

I'm guessing it's the voltage regulator, because my old one got fried, I'm putting the new one on in a few minutes and hopefully that'll fix it. All of my other instrments are working fine, except for the temp gauge and clock, but those have never worked.

 

Yeah, good chance that's it.

Worth checking your grounds, though - - all that current that fried the VR went to ground somewhere, maybe several somewheres.

Have you downloaded the 79 wiring diagram yet, from the FAQ? Real handy for problems of this type - - a roadmap to your troubles, practically.

 

Yeah I've downloaded it, I just needed to know what to look for. I put the voltage regulator in, and my tach is working fine yay!

 

Xlnt