Tach hook up

[rbbruno3]

What is the best way to hook up a factory tachometer with a MSD 6 AL box? Do I need a conversion to switch to digital ? Thanks

 

[AUSTA]

On the 6AL-2 you use the grey wire for the tacho (i put a 1k resistor in series for safety) on the 6AL you may need a filter to connect to coil .

 

[rbbruno3]

Thanks for your quick reply Austa.so I need to run the gray wire from the box to the negative side of the coil not to the tach?

 

[AUSTA]

No that would damage the box
the grey wire from the box connects to the tach wire
Orange & black wire connects to the coil on a AL6-2 there should be no other wires on the coil.
Do you have the diagram for the AL6

 

[rbbruno3]

No ,but I can find it online. it just shows the gray wire going to the tach... On my rally dash the tach has a gray with a tracer wire that pushes on a spade terminal and a dark blue wire that pushes on a threaded type terminal. So where does it hook to this?Thanks again for your help

 

[AUSTA]

The DK Blue is 12 + V input from key on.
The Grey wire with trace is signal input connect to grey tach output wire on MSD

 

[rbbruno3]

Awesome thanks

 

[quapman]

Depending on when your MSD was manufactured, you may need to get their adapter thingie for an older analog tach. If I remember, it creates a signal much like a coil would and is basically just a big electric choke.

 

[rbbruno3]

My box I bought in2013. Hooked it up like you stated no dice. Also tried an aftermarket tach hooked to the gray wire a 12 volt feed and ground . That worked fine, maybe I need the tach adapter?

 

[AUSTA]

It works on my factory rallye tacho might be a bit fussy on the signal i have a rallye dash on my other A66 with a MSD the tach doesnt work i thought the tach may have been faulty so i didnt bother .
i will have a look next week i can feed an electonic signal to see if it works if so ill let you know .

 

[quapman]

https://www.jegs.com/InstallationInstructions/100/121/121-6425.pdf

See page 7.

 

[rbbruno3]

Thanks guys I appreciate your help. I ordered a tach adapter hope this does it!!