MSD 6 and Stock Tach compatibility?

[FROSTBITE]

Well I just finished installing a msd 6 box and distributor in my Charger, after i got tired of the old ignition giving my fuel injection system fits. Now i got everything running great, except my tach isnt working so im wondering if our tachs can even read the signal off the msd 6 box.

 

[SwedCharger67]

If your original tach was connected to the negative side of the coil, towards the distributor, it can read the MSD signal, but it doesn't understand it!!

The voltage that it originally sees is quite ugly, and it's designed for it. My guess is that the MSD tach output signal is too pretty for your tach.

For calibrating my 67 Charger tach I had to hook up a coil with a spark plug, and a piece of home made electronics that could be driven from a pulse train generator. Nothing straight out from the pulse train generator (guess similar to an MSD output) could make the tach work, it needs the ugly signals with over- and underspikes.

There is available for purchase a small interface unit, that is supposed to scare our old tachs to work also with the pretty input signals. I'm going to look for it myself, and post the link if I find it, since nothing MegaSquirt puts out is dirty enough for my tach either! :eusa_whistle:

 

[Propwash]

Would this cure your problem:

 

[SwedCharger67]

Would this cure your problem:

The Summit box might work, but I was thinking about another interface box, that I haven't found yet.

It seems there is a problem with the RT-Engineering web site (rt-eng.com). This might have been the place I remembered, but maybe they have gone belly up?

I'll keep on searching to see if there is an alternative!

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I found this link in my bookmarks:
http://dtec.net.au/Tachometer Driver.htm

From Australia, for you guys in the US it might be more convenient to try the Summit one first.

 

[A383Wing]

I had to get the tach adapter box in order to get the tachometer working in the Daytona after I installed the MSD system in it. Cost me another $80 which I was not to happy with, but there was no way around it

Bryan

 

[FROSTBITE]

OK thanks guys you answered my question.