View Full Version : Digital 6 plus problems

08-25-2003, 10:27 PM
Had a problem on the highway when my 72 NOVA just died. Turned out to be the 4 pin module died and my Accell super HEI coil cracked. I had my MSD Digital 6 plus in this setup and now the car will not run if the MSD box in in the circuit. I have the Orange to B+ Ground to Ground and Black to B-, I have my tac hooked to the MSD box and 1 red to the Battery and the other to the pink wire of the distributor. The 1 White wire goes to the brown of the distributor and nothing to the center black wire from the distributor. The power comes directly from the battery. If I start the car it will run as long as a keep the rev's above 800 if I stop it will go as low as 600 then just die... I have played with the timing but I think it may have just died. Is there a way to test. It was running fine for 3 months prior to my holidays. It is out of factory warranty but I purchased a 2 year after-market warranty and I think it's time to use it....

Thanks :(

08-25-2003, 11:40 PM
I appears that you have a few wires mixed up and you are missing the ground wire from the center terminal in your cap that needs to be connected to ground. Here is how it should be hooked up.

1. MSD Orange to coil (+) terminal on cap.
2. MSD Black (18ga) to coil (-) terminal on cap.
3. GND terminal on cap to engine ground.
4. MSD Red to heavy Pink or Red wire from factory harness. This is the switched 12 volt wire from your ignition key. You should have 12 volts on this wire when starting the engine and when the key is in the run position.
5. MSD White to Brown wire that is in the harness from the distributor.
6. MSD Red (12ga) wire to battery positive (+).
7. MSD Black (12ga) wire to battery negative (-).
8. MSD Violet/Green is not used.

Please note that if you are using a 5 Pin HEI Module you may need a diode assembly to prevent hesitation or stall on deceleration. Contact the MSD Customer Service Department at (915) 855-7123 if you are using a 5 Pin Module. Here is a wiring diagram for the installation described above.


MSD Tech1

08-26-2003, 08:31 PM
Thanks for the help but it is still dead. When I said ground to ground I met the ground of the coil to engin ground. I took the cap off to make sure of the wires but it still dies whn the RPM's drop. The MSD box is not flashing any errors or anything weird, but will not work. I'm running a 4 pin HEI Module and the car runs fine without the MSD.

Any other ideas.

Thanks for the help.

08-26-2003, 11:06 PM
Some four pin HEI modules do not trigger the MSD correctly. Try installing the unit using the direct magnetic trigger method. That should clear up your problem. The below link will show you how to do the install.


MSD Tech1

09-08-2003, 10:11 PM
Haven't tried the part you suggested but did purchase a new Mallory HEI and the problems I have now are the red light is on on the Digital 6 and when I start the car it goes out and the car will not stay running, when the engine dies the red light comes back on. I have wired it up the way you said with no luck. The weird thing is that I had it running before with a 4 pin module wired the way of a 5 or 7 pin module and there is no instructions on the 4 pin module except for replacing the module with the MSD part and using the crank trigger wiring as far as I can see Now tried a new module and a new distributor with no luck. Think it still may be a 4 pin module or the unit is dead?

09-09-2003, 12:03 AM
There are a variety of different 4 pin HEI modules available on the marketplace. Some, like the GM original equipment module produce a very clean signal output that can trigger the MSD without any issues, but there are many others that cannot. I suggest using the direct magnetic triggering method to eliminate the problems you are experiencing.

MSD Tech1

Bob Gumm
09-14-2008, 12:18 PM
Sounds to me like the tech is trying to tell you to ditch the module and run directly off of the magnetic trigger. That's what I did on mine and it worked fine. I think you just have to use the magnetic trigger wires on the MSD unit.

Good Luck