MSD

[Ahoey]

I have an MSD streetfire ignition. In the instructions it tells you to hook the heavy red wire directly to the battery, heavy black to ground or negative post. The ignition works fine but the unit draws power with the key in the off position. Question 1, is this normal? checked wiring against instructions several times, positive it’s correct. Question 2, can I wire a relay to shut power off to MSD box when key is off? Any help is appreciated.

 

[mopowers]

If it's anything like a 6AL-2, there should be a thinner red wire that connects to a switched 12v that triggers an internal relay that closes the circuit for the heavy red wire. Is that not the case?

 

[Ahoey]

If it's anything like a 6AL-2, there should be a thinner red wire that connects to a switched 12v that triggers an internal relay that closes the circuit for the heavy red wire. Is that not the case?

This is the wiring diagram I used from the msd installation Manual. Using the stock electronic distributor. It seems to be a plug and play package.

 

[mopowers]

Is this small red wire connected to a switched 12v source? If so, my understanding is that no current should be drawn from the large red battery wire until 12v is applied to that small red wire. No additional relays should be necessary. If that small red wire has constant power, then that may be why there's a constant draw.

 

[jimjimjimmy]

there is a small wire that goes to switched power .

 

[Ahoey]

Is this small red wire connected to a switched 12v source? If so, my understanding is that no current should be drawn from the large red battery wire until 12v is applied to that small red wire. No additional relays should be necessary. If that small red wire has constant power, then that may be why there's a constant draw.

View attachment 1716311883

Wouldn’t the +original coil wire be on switched power?

 

[Ahoey]

Wouldn’t the +original coil wire be on switched power?

Thanks guys, you’ve given me a good clue on where to look. That will be tonights job keep you posted

 

[jimjimjimmy]

As said in post 4 hook that small red wire to switched power and all will be good . Good luck .

 

[Ahoey]

As said in post 4 hook that small red wire to switched power and all will be good . Good luck .

Yes that problem will be solved, however why is the existing positive coil wire powered when key is off?

 

[jimjimjimmy]

my guess would be because the small red wire is getting power when the key is off

 

[67Dart273]

And just how much power is being drawn? You should be able to not modify the factory wiring, and disconnect the original coil + wire, connect that wire ONLY to the small red

Also be absolutely CERTAIN you have NOTHING connected to the coil EXCEPT the two wires from the MSD. If you have a tach, use MSD destructions, and you may need a tach adapter. DO NOT connect your tach to the coil at all

 

[Ahoey]

And just how much power is being drawn? You should be able to not modify the factory wiring, and disconnect the original coil + wire, connect that wire ONLY to the small red

Also be absolutely CERTAIN you have NOTHING connected to the coil EXCEPT the two wires from the MSD. If you have a tach, use MSD destructions, and you may need a tach adapter. DO NOT connect your tach to the coil at all

Haven’t tested it yet but have a suspicion about the ignition switch. Thanks