Hey guys, me again.
I finally got the rest of the wiring for my Ramcharger project. The whole truck wiring is a 1993 Magnum setup. My engine i a 1982 360 that uses the old ignition box style.
I am systematically bypassing the PCM. All of my sensors and gauges are working, I will jumper the VSS, add external VR, and manual OD shift switch.

Where I am not sure is on the ignition wiring. It uses the 4 pin connector on the ignition box with a 2 pin ballast resistor. 4 wires come off the ignition module. 2 go to the dizzy, one goes to the coil ground, and one goes to one side of the ballast resistor, which then splits off and goes to a keyed hot.
On the other side of the ballast resistor you have a wire running to coil positive, and then splits off and goes to cranking hot wire. I will attach a pic of the schematic I used.

The point of this is so that the coil sees full voltage while the engine is cranking, but gets a reduced voltage as the truck is running and the ballast resistor heats up. However, one side of the resistor is connected to the yellow wire on the starter motor relay. The other side to any keyed hot. So if I put 12 volts to the keyed hot with the engine off, then as expected, the power will travel back through the resistor, and apply a reduced voltage to the yellow wire on the starter relay, causing that relay to chatter.

Is there something I am missing? I dont think there is any other option to using the yellow wire, its the only wire that goes hot when the key is turned to start. Unless I pull power off after the relay instead? That might solve it.
As for the keyed hot wire for RUN position, is there a typical recommended wire to pull off of?

Sorry for all the words gents, just trying to get my thoughts out.

 

on the older truck starter relays there is a special terminal that feeds that yellow wire. it isn't needed. i haven't had it hooked up since i installed my power distribution center. also you should use the asd relay to power the ignition and voltage regulator/alternator.

 

Thanks for the feedback. The ASD is where I was in the process of pulling from for keyed power. There are 2 relays connected on the same bracket, when I moved that bracket up to look for a wire, one of the relays clicked on an off a bunch of times... now Im thinking there must be something goofy going on in there... Im thinking a bad wire, likely to the ASD relay. Need to trace that now, then I can splice in.

As for the yellow wire feeding the ballast resistor, which one are you suggesting I use? Does it make sense to splice off the battery side of the starter relay rather than the yellow wire? Otherwise my relay will chatter as I am driving down the road.

 

personally i would not worry about the yellow wire. don't hook it up and see what you think. even at -20*C my truck would start just like a fuel injected vehicle without that yellow wire hooked up.

you will need to ground the asd relay to make it work. the asd and fuel pump relay are wired in parallel. i would use it to power the ignition and voltage regulator so that they see little to no voltage drop. it has been a mod i have been wanting to do to my 81 but never got around to it.

 

Perfect, that makes sense. By grounded I assume you mean they need to be screwed onto the body? Mine are floating around still, so perhaps that will explain the clicking.
I will see how it does without the yellow wire connected. That would only works however if the hot wire running to the other side of the ballast resistor stays hot while in the start position. I know some wires go dead while cranking. I assume that the ASD would have to stay hot while in run or crank, so that makes sense.

Thanks

 

the asd is normally grounded by the pcm when the computer is told the engine is cranking by the sensors. you will need to add a ground to the relay to make it come on and stay on when you turn the key.

 

Right, that makes sense. Honestly I was just going to unplug the ASD relay entirely... do I really need it? I have a mechanical fuel pump, and old CDI ignition, and a thermoquad. My alternator is going to be run by an old style voltage regulator. I can make this truck run with a paper clip...
I am only using the magnum wiring because it is plug and play and it will connect up all the gauges.

 

you don't need to but i would try powering the ignition and voltage regulator with a relay. that way the ignition and especially the voltage regulator are not having to deal with any voltage loss in the cab. it should cause the alternator to put out a bit lower voltage that is more stable.

 

Aww... okay. Now we are on the same page. I hope I am getting to the end of my list of questions. Nothing about this truck seems to be easy...
I appreciate your help. My goal is to get this thing built before I have to go back to work.
Thanks.

 

No problem. sounds like you are getting pretty close if you are at the point of wiring things.