Does anyone know a fix until I get my autometer Lunar series tach? The box is a MSD 6a.

 

From what I understand there's a filter somewhere inline on the tach wire from the coil that has to be bypassed to keep the factory tach from going screwy.

 

My fix for this was to cut the tach wire (white wire on connector with fat red wire) and run it directly off the MSD box. Works great.

 

I also have had a problem with my tachometer. I have run the car with and without the inline tach filter, and also purchased the tach filter from MSD. None of this has fixed my problem. Still wondering what I should do about it.

 

You cut the white wire only, right? Also, where did you cut it? At the coil or behind the instrument cluster? Thanks guys, keep 'em coming. All info is appreciated!

 

There is a tach filter in line. The filter is normally with in 1-11/2 feet of the coil and will look like a Small black cube. By pass this and reconnect the wire and the tach will then read correctly.

 

By bipassing the factory tach filter, will this cause damage to the factory tach and or instrument cluster? What is its function? Also, when I wire up the Autometer tach, I will run it to the box. Do I need to put a filter between the new autometer tach an the MSD box?

 

What the filter does is eliminate spikes that occur off of the factory ignition. With the box in place this no longer happens and the filter can be bypassed. The Autometer will not require it either. Regardless no damage will occur with the filter out, if you ran it on the stock ignition with out it the only thing that would happen is you would probably get some jumping out of the tach.

Thanks,

Joe

 

Thanks Joe!!