Tach Issues - Kind of works...

[SwiftJonny]

Just bought the car in the fall, a 68 Charger R/T. It has the Tic Toc Tac. The tach just bounces around a bit at idle, but is not work at all while driving. Is the tach shot and needs to be rebuilt? Not sure where to start. The car also has MSD ignition if that makes a difference. Any help would be much appreciated.

 

[5.7 hemi]

Check the ground?

 

[1badgtx]

There is a special msd adapter box that needs to be wired in so your tach works correctly...I got mine from summit,it worked for my factory tach on my 67 gtx...
Petty Blue 67 gtx

 

[SUPERSTOCKRACER]

your msd ignition is causing it.You need to buy the MSD Tach adapter. Summit or Jegs sells it. Put it in and problem solved. My 6y8 Hemi RR had the same problem. I scratched my head until I found out that the MSD doesn't work with the old style tachs.

 

[ssok]

My tach worked crappily stock. It bounced around at every RPM. With the MSD+Tach adaptor, the tac works like a dream.

 

[SwiftJonny]

Thanks a lot guys! I had a feeling something was up. I'll check out MSD's website and get one ordered up from my local speed shop.

 

[SwiftJonny]

Is this the correct Tach Adapter?
http://www.summitracing.com/parts/MSD-8910/

 

[1badgtx]

Yep thats it..

 

[SwiftJonny]

I called the MSD tech line and the guy told me to get the 8920, so that's what I ordered. Will it work as well?