RPM not working on '73 Challenger

[Loa]

Hello,

Just got a new 1973 Challenger Rallye with a dash that apparently (according to the previous owner who only had this car for 3 years) came from another car. Everything works except the RPM.

I don't really know what to look for under the hood: can anyone point me in the right direction?

Thanks.

P.S. Getting good pictures of the dash during a rainstorm isn't easy! Sorry for the crappy pics. 

[burdar]

There should be a single wire coming through the firewall below and to the left of the brake booster.(when standing at the front of the car)  The wire should be gray with a black stripe.  That wire needs to be connected to the - side of the coil.  If that's hooked up correctly, check to make sure the connecter is plugging into the back of the gauge cluster.  If that is hooked up, then your tach needs to be rebuilt. 

[Loa]

Thanks for the concise reply! I'll check it out when the rain stops!

[MEK-Dangerfield]

Your tachometer is toast.

  It's common for them to die. The needle should be at zero when the car is off.

[blown motor]

But just becase the needle goes to 0 when the car is off does that mean it's working 'properly'? Mine goes to 0 but reads about 3500 RPM at 60 mph which can't be right for a 340/904 with 3.23 gears.

[MEK-Dangerfield]

But just becase the needle goes to 0 when the car is off does that mean it's working 'properly'? Mine goes to 0 but reads about 3500 RPM at 60 mph which can't be right for a 340/904 with 3.23 gears.

You are correct. It isn't right. They tend to read high as they get old, and need to be re calibrated.

I have 3:23 gears, and read about 2600 RPM at 60 mph.

[blown motor]

Where do I send it to get it recalibrated?

[MEK-Dangerfield]

Where do I send it to get it recalibrated?

 I sent mine here. I had to get a rebuild since mine was dead. 

The website is under construction, but if you click on the "contact us" tab at the top, you can get the phone number. I believe the guy I dealt with was named David. He did fantastic work.


   http://performancecargraphics.com/

[ToxicWolf]

I sent mine here. I had to get a rebuild since mine was dead. 

The website is under construction, but if you click on the "contact us" tab at the top, you can get the phone number. I believe the guy I dealt with was named David. He did fantastic work.


   http://performancecargraphics.com/

  I got mine from Dave too. Very happy.