stock tach not working after MSD install

Jmood

New Member
Nov 14, 2002
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Arkansaw
I already posted in the power-adders, with no replys...... I just wired in a MSD boost retard, and the stock tach quit working, is there a way to get the stock tach to work with the boost retard? I think its the green/yellow wire on the coil, can I just splice? thanks.
 
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When I installed an HEI distributor, I took the intrument cluster out and ran a wire off the back of the tach, straight to the coil. I have since returned to using duraspark for smog reasons, but when I hooked up all the factory wiring, the tach didn't work. So I used that same wire and ran it straight to the stock coil. There should be three "prongs" on the back of the tach, and if I remember right, I hooked the wire up to "the one in the middle"
 
When I installed an HEI distributor, I took the intrument cluster out and ran a wire off the back of the tach, straight to the coil. I have since returned to using duraspark for smog reasons, but when I hooked up all the factory wiring, the tach didn't work. So I used that same wire and ran it straight to the stock coil. There should be three "prongs" on the back of the tach, and if I remember right, I hooked the wire up to "the one in the middle"


That's my problem...i stopped running a Duraspark and now my stock tach doesn't work (no idea why because i don't think the tach runs through the duraspark). I'm planning on making a whole new engine harness for mine since it's carbed and i only need a few wires for the engine.
 
If you are carbed an using a Duraspark, the tach runs off the neg coil terminal. There is a wire from the neg coil terminal to the tach signal input terminal through the harness. The connection from the dash harness to the back of the cluster is a problem on all of mine, and a problem there may be why your extra wire worked so well. You really should not need the added wire.

I have a Jacobs on one car, and needed a tach adapter.

I have an MSD Digital 6 on the 82 Mustang, and it has a tach output connection, which runs the stock tach just fine. It is connected to the original tach feed wire . That was one reason I bought it, having suffered through the Jacobs problems. Only problem now is the connection at the printed circuit board is old so the tach stops when it's cold out!
With the regular 6al, I think the MSD tach adapter is the best bet. Call MSD and ask, as there are several versions of their tach adapters.
 
i got this same problem,i think im gunna try and run that single wire from the factory tach like you did.middle wire you say?

I believe so. There are three threaded studs sticking off the back of the tach. Make a wire with a ring fitting crimped on and then find a small nut that threds on to the stud to fasten it down. Somehow I figured out which one was the right one, I think by seeing where that green wire with the yellow stripe led to. Like RD said there is like a printed circuit board on the back so follow that. I think you'll figure it out.
 
If it runs from the tach directly to the coil, then yes because it is totally independent. But I think even if there is a wire coming off your MSD box for the tach, then it should also work. I just noticed you have a 96 stang though, so I'm not sure what your tach looks like. We were discussing the 85/86 tach.