12v Ignition Wiring Help

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BSki
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12v Ignition Wiring Help

Post by BSki » Tue Jul 29, 2014 5:54 pm

Hi all, close to actually driving her, but over my head on the ignition wiring. New wiring harness from Ron, all new and/or rebuilt components. Just don't have the same options as provided on the G503 wiring diagram. Have a ballast resistor, voltage regulator does not have the same connections, etc... Here is a rough picture of the components, any help would be appreciated.

Image

I think I got that picture link thing right.....

Brian


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Re: 12v Ignition Wiring Help

Post by Phil Pizzi » Tue Jul 29, 2014 6:26 pm

It's pretty much the same as standard except the wiring from the voltage reg to the alt.
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Re: 12v Ignition Wiring Help

Post by BSki » Tue Jul 29, 2014 8:18 pm

Where / how do I wire the ballast resistor?

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Re: 12v Ignition Wiring Help

Post by artificer » Tue Jul 29, 2014 10:21 pm

If you are running a 6V coil the ballast resistor is in the normal running ignition circuit....always.
If you are running a 6V coil but have a keyed ignition switch there should be 12V to the coil in the starting position then 12V reduced to 6V through the ballast resistor in the normal running, non starting ignition position.

Image
Just ignore the electronic ignition module section of the diagram.
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Re: 12v Ignition Wiring Help

Post by Wolfman » Wed Jul 30, 2014 5:43 am

The ballast resistor is installed in the wire going from the ignition switch to the coil secondary positive post.
I usually put it just behind the coil and mount it to the coil mount stud.
Connected in series. Wire from the ign. switch to one end of the resistor and a wire from the other end of the resistor to the coil + post. It gets hot with the key on. Keep that in mind.
No ignition by pass on an old jeep.
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Re: 12v Ignition Wiring Help

Post by BSki » Wed Jul 30, 2014 8:02 am

Thank you, I have two connections that I am still unsure of.

From the Voltage Regulator is a post / wire labeled "ign", I think this would go to the two post junction block left side finding its way eventually to the ignition side of the ammeter?

The other is the wire coming off the "bat" post on the alternator. Was initially going to just connect this directly to the positive terminal on the battery but my neighbor suggeted the foot starter switch instead using the same post and the primary postive battery connection. I do not see a difference?

Brian

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Re: 12v Ignition Wiring Help

Post by W. Winget » Wed Jul 30, 2014 9:30 am

If it's a GM altenator, the "bat" should be connected to the battery post, but your friend is correct, if you want to hide it a little, you could wire it to the HOT side of the foot starter switch. Just harder to get to in the future.
From memory (and mine) you have to rev the engine to above 1200 or so RPM for a second for the internal regulator to sense a charge requirement, then the altenator will kick in. It will not charge at idle if merely started and not tweaked into the RPM range for a short second.
1200 is not very high either, but it's something I've always done to ensure the alt does kick in, unlike my other vehicles.
V/R W Winget

PS: if the ign wire is coming off the altenator, it may be the one for the modern idiot light, this can be eliminated, or back fed to complete the circuit if desired. WAW

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Re: 12v Ignition Wiring Help

Post by omtay77 » Wed Jul 30, 2014 10:21 am

If you are running a 6V coil the ballast resistor is in the normal running ignition circuit....always.
If you are running a 6V coil but have a keyed ignition switch there should be 12V to the coil in the starting position then 12V reduced to 6V through the ballast resistor in the normal running, non starting ignition position.
At the risk of hijacking the thread....Artificer, you mentioned 6V coil...what is the difference if one is running a 12V coil (in a 12V keyed ignition system)?...is a resistor still used somewhere in the circuit?

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Re: 12v Ignition Wiring Help

Post by Marty, SoCal » Wed Jul 30, 2014 12:02 pm

You can buy a universal 12V coil with the resistor built in. Standard part number UC15 or UC15T will work fine without an external resistor and should fit the stock bracket. A 12V coil that will work should have about 3 Ohms resistance across the primary circuits. Stock 6 V coils are usually around 1.5 ohms.

I found this web post searching for a good picture of the circuit for a 3 wire GM alt:
http://www.homesteadingtoday.com/5407847-post5.html

If you hook up a three wire GM alternator and you do not run a indicator lamp, the ignition sense wire will need either a resistor or a 1 amp diode in line with the stripe to the alternator to keep the power from feeding back into the ignition system which will keep the engine running when you shut the key off. The #2 wire is best connected as close to the battery as possible which will be either at the battery or at the stud for the floor switch. The main battery post on the alternator will be feeding through the ammeter or your ammeter will never show a positive charge. The 3 wire alt will control the voltage better than a 1 wire, when you are using an ammeter or have multiple connections between the alt and the battery, the sense wire #2 right at the battery will read the true battery voltage, not what the voltage is after going through all the connections which unavoidably will drop voltage causing an overcharge and shorter battery life.
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Re: 12v Ignition Wiring Help

Post by artificer » Wed Jul 30, 2014 12:43 pm

Tom wrote: You mentioned 6V coil...what is the difference if one is running a 12V coil (in a 12V keyed ignition system)?...is a resistor still used somewhere in the circuit?
The type of resistor referred to in this thread is not needed in that case. The ballast resistor is primarily used the give extra oomph for starting.
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Re: 12v Ignition Wiring Help

Post by Wolfman » Thu Jul 31, 2014 5:02 am

Confusion is running rampant, again.
To start with, Brian, What make alternator are you installing. General opinion is, it is a Delco Remy with an internal regulator. ????
As far as I know, on todays market, there are 3 versions of this type available.
1. The orignal. Big Battery post on the rear. Two flat spade connections on the side marked 1 and 2. #1 connected to the ignition, usually through the idiot light on the dash. Switched on and off with the ignition switch. Needed to be wired as Marty described or you would not be able to shut the engine down, as Marty said. #2 was connected to battery Positive and is hot all the time. Closer to the battery ( as Marty said ) would be better but GM wired there larger trucks by connecting the #2 wire directly to the Big battery post on the rear of the alternator with just a short jumper. Gonna argue with the GM enginneers ?? Good luck arguing with any enginneer ! :lol:
2. Second version had the big Battery connection on the rear but only one wire coming off the side, flat plug. It connected to the ign. A diode was built in to the connector so this wire could be connected to the coil + side with no ill side effects.
3. Third version was the one wire. Only connection on the alternator was the big battery terminal on the rear of the alternator. No side connection. Connect the big battery wire and go.
All three has a ground connection on the rear of the alternator case.
If you are installing something beside a GM internal reg. alternator, we need to start over.
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Re: 12v Ignition Wiring Help

Post by BSki » Thu Jul 31, 2014 10:51 am

Thank you everyone. I was told it is an older Mopar (Dodge) alternator. It has three wire connections on the back; ground, field and battery. The voltage regulator that came with it has only three connections as well; field, ign and ground.

I was able ot fire up the jeep last night and it seemed to run well. I just can't tell if the alternator is charging as the ammeter is not reading.

My coil says 12v on it, but came with an external resistor of some sort. It seemed to work last night. When I held the test light to the battery side of the resistor is shone brightly, noticably less so on the coil side post.

Brian

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Re: 12v Ignition Wiring Help

Post by Marty, SoCal » Thu Jul 31, 2014 11:26 am

Do you have a volt meter? Check the battery voltage, engine off, should be somewhere around 12.4 if the battery is charged. Start the engine, the voltage should climb to around 14.2 volts.

Don't have a voltmeter?
Take a screwdriver and with the engine running, se if the screwdriver blade will be magnetically attracted to the rear case of the alternator, at the shaft bearing. If the alternator is charging, the screwdriver will be attracted to the shaft's magnetism.

Another quick check, is to turn on the headlights, then start the engine, the lights should brighten noticeably.

If you have the ammeter in the dash, and the alternator is charging, but the ammeter won't read the charge, make sure you have the alternator power stud feeding power to the back of the ammeter in the same path that the stock G503 generator was originally wired, not the starter switch stud.

Two basic types of old Mopar alternators, one has an isolated field, with two brush connections, the other type has one brush connected to the case (ground) and the other connected to the field. Two types of regulators,and one type for the grounded field alternator, (usually a points type regulator with screw terminals, but there is a solid state replacement available) , one for the isolated field, with a solid state regulator that has a rubber plug connection.

Down at the bottom of this webpage is a simple wiring diagram for both types:
http://www.allpar.com/history/mopar/electrical.html
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