12V switched and on start ?

[SHX669]

I've got a '76 with factory wiring and Duraspark II ignition module and dizzy.
I'm thinking about replacing the DSII dizzy with a MSD Ready to Run and it { and the coil} requires 12v at "start" and at "run". So the question is can I use the red/blue wire and the blue wire that supply the module ? If not where can i "tap in to " - or should i replace the section of ' resistor wire " with a regular wire and use that and another wire to the starter relay ?
--- And no i don't want to use a 6AL box or a Pertronix II module -- one of my Broncos already has a MSD R to R dizzy so I'm trying to keep common parts when possible --- Oh and I'm thinking of replacing the DS II dizzy because QUALITY replacement parts are getting hard to find .

 

[Broncobowsher]

You tie the "I" wire off the solenoid into the run wire to make sure you have power during start. The ignition switch having power to run while in start is questionable. Often it does it naturally, but I have been bit a few times where I would loose the run wire power while the starter was spinning away. Maybe 5% of the times I go to start the engine that happens. That is why there is an "I" wire off the solenoid, to power the ignition system during crank (and from the factory it bypasses the ballast resistor to give a little more spark)

 

[SHX669]

I'll have to look to see if the throttle solenoid wiring is still there . I've had the Bronco 16 years but who knows what the POs did the 24 years before i bought it.
I've been running the DS II on both Broncos { 68 with a 351C and the 76 with 5.0L then with a 351w } and never had any issues with either of the modules . But not to go into too much detail - I've had issues with finding a reliable magnetic pickup for the 76 with 351w and/or a decent quality DS II distributor . Earlier this year i looked into Davis Unified Ignitions they were supposed to have a better DS dizzy but I was never able to verify that.

 

[B RON CO]

Hi, I don't remember the exact years for the change but I thought the duraspark were all 12 volt without a resistor wire. I do think I remember that if the solenoid has only 1 small post the ignition always gets 12 volts, on start (cranking) and run. I would check it with a multimeter. Good luck

 

[Broncobowsher]

The DUIs are good, the clones are junk.

 

[DirtDonk]

Hi, I don't remember the exact years for the change but I thought the duraspark were all 12 volt without a resistor wire. I do think I remember that if the solenoid has only 1 small post the ignition always gets 12 volts, on start (cranking) and run. I would check it with a multimeter. Good luck

Correct as far as I know. Pretty sure that all year EB's kept the resistor wire, but it only powered the coil itself. All DS and DSII modules got a full 12v.

Correct too, on the dual post vs single post starter relays. But as far as I know, all EB's kept the old standard dual-post model with Brown "I" wire to the coil and, in some cases, the DSII module.

Paul

 

[SHX669]

Ya the '76 has the resistor wire but not sure if it ever had the carb solenoid.
Ok - How bout the the blue wire and the red/blue wire that powers the Module ? I'm clueless when it comes to auto electric but it looks to me like one wire has 12v on start and the other has 12v on run going to the module ???

 

[Steve83]

Do not join the crank signal circuit (R/Bu) to any other circuit - you'll cause a LOT of problems. Only the A terminal on the ig.sw. (Bk/Gn) turns OFF during cranking; the I terminal (Gn/R & R/Gn or Pk) stays hot, so that's the correct circuit for any ignition system. Gn/R becomes Bu at S203 and powers the factory ignition, so that's what you should use - the factory wire for its factory purpose. Click this (the page may be slow to load):



You should read some of the old threads here about MSDs catching fire.

 

[DirtDonk]

Steve's correct. Yes, your module probably uses it's own separate Red w/blue wire as one of it's start-sensing wires, but in the module it's separated from feedback. Once you try to literally tie them together, you're sending a signal back to the starter relay to try to start the engine as soon as you turn the key to RUN.

I would first try just the Blue wire at the module for your START and RUN duties. If your ignition switch is working properly, this should have power in both positions.
If it does not, and by some '76 diagrams that is questionable, you can tap into the Brown "I" wire from the starter relay to get your START signal.
Using the I circuit won't allow voltage to energize the starter relay prematurely until the unit actually fails.

Paul

 

[SHX669]

Thanx for the info guys - i think i'm making a plan - LOL
Steve I'm aware of multiple people with issues with the 6al box including melting that's one of the reasons for the "Ready to Run " - no box and a little more benign.