EFI and MSD

I have the MSD digital 6 box with the gray wire for the EFI signal. Question is can I split the gray wire to run my tack and EFI unit?

I've hooked up a few 6al boxes, but never on EFI. You could always try your
method and see what happens, or better call the MSD tech. Maybe someone
here has done this before and will answer your questions.
Good Luck

Edelbock said no MSD said yes. There has to be away

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Originally Posted by bobsundance

Edelbock said no MSD said yes. There has to be away

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On your other thread you said,

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Now Edelblock says don't use the ground off the MSD unit from a Digital 6A box to the car tach, and to call MSD; and MSD says its fine to use it for both.

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Is this gray wire a ground or the rpm pulse signal?

we obviously dont know how to help you fix this .. i doubt any one of us has experienced this .. your only hope is help from edelbrock ..quit beating us up cause we cant fix it ..

am just looking for someone who has Edelbock EFI and MSD box that runs a Tach in there car to see if the gray wire well run both or not, but I guess from what you say nobody does this and there is no help here OK thanks

Forget the tach for now, wire it per instructions and see if you can get past the air/fuel problems with Mark's help. If you get it running right, then you can try paralleling the two signals from one output to get the tach functional. Focus on the real problem first, then the secondary crap.

http://www.clubhotrod.com/engine-tun...tml#post532157

This vacuum issue might well be your problem, too, Bob. Did you tell the shop that did your engine that you were looking at running EFI? If not they may dumped in a cam with too much overlap that bleeds off your vacuum at idle & cruise. That was one of the key questions from my guy when we were discussing the needs for my engine.