I have 1-2-3 dizzy and a Smiths programmable tach. My tach never worked since new—the needle would bounce from peg to peg. I had no less than 3 automotive electronics shops try to get it working. They all decided the tach was faulty. One shop wanted $300 for the effort.

After poking around on the Internet, I found lots of references to tachs  not working when used in conjunction with high output coils; mine’s rated @ 40kv. All of the speed shops (Speedway, Jegs, etc.) sell a filter that eliminates this problem. 

I bought one, but before I had a chance to install it, I bought a rev limiter. The limiter has a dedicated output wire that connects directly to the tach. Problem solved.

If it turns out your tach’s not working properly once you’ve got it hooked up, contact me off-line with your mailing address and I’ll send you my unused filter.

 

Cool, thank you!   I screwed up a new combo gauge a few weeks ago so I am a little paranoid about doing this one in too!  

I have one of these installed. 

Just ignore the red/blue (per instructions) and the solid red. 

White/black to neg side of the coil (I also have a 123 distributed). 

I tied red/white together with the green so the light is always on when the power is on via the key. 

Switch 1, 2, and 8 are on - all others are off. 

Works fine for me. 

Thanks for all the answers.  I should have been clear.  The harness pigtail that comes with the gauge has all the wires listed including the red/white but also has a solid red wire which is not discussed in the instructions at all.  I suppose I can hook everything up per instructions and leave the red out of the mix.  If it works then all is good and if not, I'll go from there.   

I don't know how the Smiths works specifically, but most "points" tachs take their signal straight off the negative terminal on the coil. So it doesn't matter which type of distributor is used to collapse the field.

It says red/white illumination, I think it could be red or white easy to check though.

1) Probably the wire for the tach light bulb so wire it into the panel lights.
2) you don't have contact breaker points?

By the way, these are the instructions that came with it,  No mention of the red wire https://www.caigauge.com/documents//pdfs/pil048-iss1-flt-prsm-tacho-360.pdf

I am trying to figure out how to wire a 52mm programmable Smiths tachometer to my Mini with a 123 distributor.  The wiring on the tachometer instructions says to connect the green wire to a switched power source, the black wire to ground, the red/white wire to a 12 volt source, and the white/black to the contact breaker or ECU (or alternator for diesel only).  It also says not to use the red/blue.  

Here are my questions:
1) there is also a solid red wire that is not mentioned.  What do I do with it?  

2) What do I connect the black/white wire to since I don't have a contact breaker or ECU?  Do I connect it to the negative side of the coil?   

3) What about the switches?  

Any help would be appreciated since this little sucker was expensive and the last thing I want to do is fry it!