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Please explain the "start" circuit to me
https://slantsix.org/forum/viewtopic.php?t=36424		 Page 2 of 3
Author:  56 Dodge [ Sat Jul 25, 2009 4:12 am ]
Post subject: 
You clip the wire going to pin 3 on the ECU. That should be the 5 ohm side and just run the bottom side which is about 1.2 ohms stock. I rewired mine with a MSD .85 ohm resistor so I get a full 10 volts to the coil at 600 rpm. All modern ECU's just use 4 pins.

I just sent the schematic if needed. Tis another one of those items that should be a sticky. :!:[/quote]
Ted, can you post the shcematic of this change I would like to see it to go from a double to a singlballastst resistor also what part number did you use for the 85 ohm MSD resistor?
Author:  Jester [ Sat Jun 26, 2010 1:38 am ]
Post subject: 
I'm having exactly the same starting problems with my Dart. It will crank over fine, but will not fire. Not even a little. But when I release the key, it will fire for a brief moment. What's strange is I have a new MSD coil, a new ECU and run a new single ballast resistor. This stuff has about 500 miles on it.

I carry a new spare coil, ECU and ballast in the trunk... So tomorrow, I'll try jumping the starter while the ignition's in the run position, then try the ballast resistor, then the coil and the ECU.

I'll be happy to hear it start. She died as I rolled into my underground parking spot :(
Author:  Rick Covalt [ Sat Jun 26, 2010 6:42 am ]
Post subject:  Hei
HEI , HEI, to the rescue!!! :D Eliminate Mr. Ballast!

Rick
Author:  wjajr [ Sat Jun 26, 2010 8:03 am ]
Post subject: 
Jester:
Quote:
I'm having exactly the same starting problems with my Dart. It will crank over fine, but will not fire. Not even a little. But when I release the key, it will fire for a brief moment. What's strange is I have a new MSD coil, a new ECU and run a new single ballast resistor. This stuff has about 500 miles on
it.


If the resistor is bad, engine will fire while being cranked, when key is released engine dies. Resistor is by passed when starter is engaged, comes on line when key is in run position.

Have you checked resistance, and gap of the magnetic pick-up in the distributor? Should be minimum around 150 ohms, and gaped 0.007 inch.

Resistor will be 6 to 10 ohms depending on which one you have. If it reads a lot higher, the filament is broken, and no good.

Coil:
Resistance primary side between (+) & (-) terminals 0.75 to 0.81 ohms
Resistance secondary side between (+) or (-) and high voltage socket to distributor has to be 10,000 to 11,000 ohms for a stock unit. Blaster will be a bit different, but roughly same proportions.

I run a Blaster II coil, their resistor, and Mopar orange box, and the car runs fine. You have a component or two in the ignition circuit that is off spec. or not functioning, or a faulty conductor.
Author:  Aggressive Ted [ Sat Jun 26, 2010 9:15 am ]
Post subject:  MSD Resistor part number
56 Dodge,

Sure, Here are the part numbers.....the resistor number is #8214 - Coil Ballast Resistor 0.8 ohm. It comes with the Chrome Blaster 2 Coil, w/Ballast Hardware Part No. 8200.

As SL6Dan said, your getting a full 12 volts when the key is in the start position which bypasses the resistor. Once it starts, then your going through the resistor. Basically the ignition key switch is triggering the starter solenoid which then connects the battery directly to the starter. There is also a line that goes directly to the coil. That's how you hot wire a car. Short the solenoid with a screw driver and wire the coil for a full 12 volts and your off and running.........done it many times when ignition key switches have worn out. In fact, I have even installed a push button to start some of my old trucks, just like a old farm tractor.

Wjajr and I are both running the same setup.

The sticky for the schematic is in the HEI wiring instructions for going from a dual to a single resistor. Frequently Asked Questions - Electrical
Also the MOPAR site www.MOPARTS.com has several good photos like this one http://www.moparts.org/Tech/Archive/elec/3.html and on another site http://duster318.freeservers.com/tech/hei.html
Author:  Jester [ Sat Jun 26, 2010 12:25 pm ]
Post subject: 
I checked all my connections and then tried starting again. No fire. replaced the ballast resistor and tightened the bolts to the ecu (can't remember if the ecu needs a good ground?). To my surprise, it started right up and drove beautifully all the way to my parents house (I keep my tools there).

Turned the car off and started it fine a few times. Figured it must have been a connection I wiggled or something, so I replaced the ballast resistor with the old one and... no start. Put the new one in and it starts fine.

This basically goes against what everyone has said, although it is a Single ballast resistor in a converted EI from points ignition system. Maybe I wired something wrong?
Author:  wjajr [ Sat Jun 26, 2010 2:57 pm ]
Post subject: 
I ran a wire from the screw attaching the chassis of the ECU over to the firewall ground bolt which also has a braided grounding conductor to the head to make a good ground. Depending on a course thread bolt projecting into the wheel well dose not make for a reliable ground when everything starts to corrode, as my ECU is mounted on top of the inner fender.

Just curious, did you check the resistance of your bad resistor? I’m wondering if one of your female spade connectors is faulty that connects to the resistor, and not the resistor its self.

Anyway, glad you got it running.
Author:  Jester [ Sat Jun 26, 2010 3:20 pm ]
Post subject: 
It has infinite resistance. Strange.
Author:  wjajr [ Sat Jun 26, 2010 4:20 pm ]
Post subject: 
Jester:
Quote:
It has infinite resistance. Strange.
Ahhh good, not strange at all. That means the resistance coil inside of the ceramic has broken not unlike a filament in a light bulb will brake. In other words the circuit is broken or open, no juice will flow.
Author:  Aggressive Ted [ Sat Jun 26, 2010 6:14 pm ]
Post subject: 
Jester,

Now that you learned about resistors, the next step is to delete it.
Buy a Pertronix 3 ohm coil and wire the leads together and never use the resistor again. You can buy a normal style round 3 ohm coil or the HEI style. You will love not having to worry about the resistor again! :)

And yes the ECU has to be grounded to work properly.
Author:  Jester [ Sat Jun 26, 2010 8:45 pm ]
Post subject: 
lol, I'll just carry a spare everywhere I go for now. Still have 2 brand new coils to go through ;)
Author:  Charrlie_S [ Sun Jun 27, 2010 4:01 am ]
Post subject: 
If it will not start with a bad ballast resistor, but starts with a good one, you have the "ignition #1" and "ignition #2" circuits reversed. With a good resistor installed and the starter wire disconected from the starter, turn the key to "run" and measure the voltage at the coil + to ground, it should be someware between 6-9 volts, depending on the resistor value. Then check the coil + voltage to ground while the key is in the "start" position, should read battery voltage, about 12v.
Author:  Jester [ Sun Jun 27, 2010 12:07 pm ]
Post subject: 
I don't get how I could reverse the ignition 1 and 2 circuits? it was wired the same way when it had points, wasn't it?
Author:  Charrlie_S [ Sun Jun 27, 2010 3:26 pm ]
Post subject: 
Quote:
I don't get how I could reverse the ignition 1 and 2 circuits? it was wired the same way when it had points, wasn't it?
I don't know, how it was wired previously. After all these years, someone might have made a mistake. It is a simple thing to check it.

I am working on a 72 Dodge pick up that someone added electronic ign, and couldn't get it started. Main problem was a bad distributer pickup right out of the box. After repairing that, I started the truck by having the key on, and jumpering the starter relay. When trying to start the truck using the key, I had the same symtom, you had "no start, until releasing the key".
They didn't connect the start circuit wire to the correct terminal on the resistor.
Author:  Jester [ Sun Jun 27, 2010 4:19 pm ]
Post subject: 
there's only 4 wires going to my ballast resistor. two orange ones on one side and two brown wires on the other side. Plus the wire from the ECU.

Don't see how they could be wired any differently. It was untouched previously, stock points system.
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