Will Bypassing Ballast Resistor damage stock ignition module?

[TA/Z06/GSXR1100]

This article says no to the ballast resistor if you don't have points.

https://www.hotrod.com/articles/mopp-1110-ballast-resistor-guide-ballast-blast-off/

If this was true, why would the factory electronic ignition introduced in 1972 still use a ballast resistor?  If the factory used a ballast resistor with a stock style ECU, I would do the same. 

I believe the ballast was there to protect the older oil filled coils from the full 12v... they simply could not handle it.

My 74 has the single ballast and a 4-pin chrome box, using the same Petronix coil the FBO kit comes with.

Based on info above and a few wiring diagrams I've reviewed,  I believe it's safe for 4-pin ECU to bypass the ballast as long as the coil is up to it.

Happy to be the crash test dummy here... if my ECU burns up I'll be sure to report back.

Thanks for the replies and info guys!

Constant 12V is hard on coils . Issues tied to Long term reliability ....

I learned this in auto-tech class , circa 1980. Not sure if this still applies. Jut throwing it out.

[Scooter]

Quick follow up on this... looking for a more permanent ballast bypass than my jumper setup.

Think this diagram is accurate:


At startup do both the start and run circuits get 12v?

Thinking of making a permanent connection from the blue "run" circuit to the coil, but need to verify it gets power at startup as well.

[Burdar]

The brown wire gets power from the ignition switch in "start".  The blue wire does NOT.  Once you let off the key, power drops off the brown wire and goes to the blue.

[Bullitt-]

 :that diagram is not accurate IMO..
   Confusing at best

[mopar jack]

The ballast resistor also compensates for temperature and rpms. This  link gives a good explanation for the original use of a ballast. http://blog.simonbbc.com/ballast-resistors-resistance-and-coils/

[Scooter]

The brown wire gets power from the ignition switch in "start".  The blue wire does NOT.  Once you let off the key, power drops off the brown wire and goes to the blue.

So the 2 wires from the ignition switch are brown and blue. Guess I need to locate a better diagram.

If that's accurate it sounds like simply tying the brown and blue together prior to the coil and bypassing the ballast would do the trick yes? 

[Shane Kelley]

My experience with running a full 12 volts+ all the time to the coil will result in coil failure. I had many people try to tell but I kept reading this article here and there how it would work just fine. I was bullheaded and couldn't see any reason why it shouldn't. After breaking down a half dozen times do to coil failure I went back to running a ballast resistor. I probably tried 4 different brand coils and it didn't matter. Haven't had one issue since going with the ballast for the last 2 years. 

[Burdar]

My experience with running a full 12 volts+ all the time to the coil will result in coil failure. I had many people try to tell but I kept reading this article here and there how it would work just fine. I was bullheaded and couldn't see any reason why it shouldn't. After breaking down a half dozen times do to coil failure I went back to running a ballast resistor. I probably tried 4 different brand coils and it didn't matter. Haven't had one issue since going with the ballast for the last 2 years.

The coil has to be designed to run without a ballast.  Most coils are not.  Pertronix sells two coils.  One is oil filled and the other is epoxy filled.  Both are designed to run on 12v.

[Shane Kelley]

That's what I was thinking as well. I actually tried their oil filled one. It died as well after about a month. 

[dodj]

The brown wire gets power from the ignition switch in "start".  The blue wire does NOT.  Once you let off the key, power drops off the brown wire and goes to the blue.

So the 2 wires from the ignition switch are brown and blue. Guess I need to locate a better diagram.

If that's accurate it sounds like simply tying the brown and blue together prior to the coil and bypassing the ballast would do the trick yes?

That is what is normally done when changing to an MSD Ignition that was designed with no ballast

[Scooter]

The brown wire gets power from the ignition switch in "start".  The blue wire does NOT.  Once you let off the key, power drops off the brown wire and goes to the blue.

So the 2 wires from the ignition switch are brown and blue. Guess I need to locate a better diagram.

If that's accurate it sounds like simply tying the brown and blue together prior to the coil and bypassing the ballast would do the trick yes?

That is what is normally done when changing to an MSD Ignition that was designed with no ballast

Had to do the same bypass on my Ford when I installed the MSD dizzy and 6AL box. Except Ford uses a "pink" resistance wire instead of a ballast resistor.

Found another diagram for the earlier 5 pin ECU unit that states the run position has power at all times:



Cant imagine the ignition changed for the "73-74" 4 pin ECU with single ballast.

This would make life a bit easier as I could just terminate the start leg and wire the run leg right to the coil.

Would it make any sense to not have the run leg have power at startup and for the ignition circuit to actually have to transition from start to run with a complete dropout of volts between the two ignition positions? 

On the coil issue, Petronix says full 12v for this application:



Gotta hope they know their own coils... lol.

[Burdar]

Found another diagram for the earlier 5 pin ECU unit that states both the run and start positions have power at all times:

Test it and report back.  Disconnect the ignition switch connector at the base of the steering column and test both the blue and brown wires.  With the connector disconnected, you won't be getting any feedback from the brown wire since it's spliced to the blue at the ballast.  You'll be testing just the ignition switch to see how it distributes power.

[Scooter]

Found another diagram for the earlier 5 pin ECU unit that states both the run and start positions have power at all times:

Test it and report back.  Disconnect the ignition switch connector at the base of the steering column and test both the blue and brown wires.  With the connector disconnected, you won't be getting any feedback from the brown wire since it's spliced to the blue at the ballast.  You'll be testing just the ignition switch to see how it distributes power.

Looks like I'm going to have to crawl up under there.

Modified the above post to reflect actual thought...lol

"Found another diagram for the earlier 5 pin ECU unit that states the run position has power at all times"

need more coffee.

[Burdar]

I knew what you meant. Would be interested to see if the blue wire still has power during "start" though.