One wire alternator problem

-
russhal

russhal

Well-Known Member
Joined
Mar 21, 2013
Messages
230
Reaction score
9
Location
Dothan Alabama
Recently I converted my car to a one wire alternator. It's a 71 swinger so it had the newer style regulator. I bought a tuff 1 one wire 100 amp Chrysler alternator from summit racing. I also bought an 8 gauge alternator wire. When I installed the alternator, I also grounded it to the chassis as per the instructions. When I removed the voltage regulator, I removed the field wires which splice into the ballast resistor. This was a good 12 volt ignition source under hood. I had my msd ignition wire spliced into the ballast resister wires. Shortly after the conversion, I started having ignition problems. The voltage at the ballast resister now fluctuates. I know the msd ignition source has to be 12 volt but why is the voltage fluctuating when the car is running? Its 12 volts key on. Then when the car starts, it jumps up as high as 16 and as low 0 which of course make the car die. The voltage at the battery is about 14 to 14.5 constant. The 8 gauge wire goes from alternator to battery.
 
My friend is having the same issue with a Powermaster 100 amp on a customers car. Started immediately after installation. He completely removed the ballast resistor, with a MSD it wasn't sopposed to be there anyway, and spliced the wires together. Problem went away, he figured it was just a bad connection or shorting ballast.
 
I would agree it was the ballast resister but I'm wired in on the bulk head side. The wire that used to attach to the alternator is not used. Power used to go through the car to the battery. Now it comes from the battery to the car. I hate wiring. I've checked every connection from the battery into the car and back out. 12 volts without the car running all the way to the ballast resister. Thanks for your in put ChrisPerry
 
Except for the alternator wire, is the car wiring pretty much factory?

You need to check the circuit path carefully from the battery all the way through the harness connections, back out to your ignition run point under the hood. In a factory stock car that path amounts to........

Battery.......starter relay "stud"..........fuse link.......bulkhead connector (RED).......to ammeter......through ammeter........(BLACK).......to main splice in black wire.........

branch off from splice.........

to hot buss in fuse panel..........

to headlight switch............

to ignition switch.........through connector.......through switch.......back through connector "blue run"........back out through bulkhead connector.........terminate at ballast connection(s)

If the battery "running" stays stable at nominal 14V then it HAS to be in that path somewhere.

You need to check this under "some load." One way to do that is to find something that operates off 12V, such as a headlight, or a stop/ tail lamp, or other 12V device that draws at least a couple and maybe 4-5 amps or so. Wire that device to the "run" point under the hood, and with the key in run, engine off, go over all the points in the circuit path

You need a good diagram, which to me means FACTORY.

You can download several years factory service manuals from MyMopar. A few of those came from the guys here at FABO

http://www.mymopar.com/index.php?pid=31

Your most likely suspects are the

bulkhead connector

Ignition switch

Switch connector

Any fuses/ fuse links in the circuit

Ammeter and connections

If you still have the ammeter wires and have bypassed them, check out the termination at the splice. Don't forget the end terminals themselves can be bad inside the wire/ insulation
 
The wiring is totally factory. I have a friend suggesting that I leave the wire direct to the battery and connect the factory alternator to the alternator. I don't feel good about that. I've checked the wiring from the battery into the car, through the amp gauge back out the ballast. I haven't checked anything else. This was with the car not running. 12 volts at every source. Thanks 67Dart273
 
Have you read the Mad article? That gives a VERY good overview into what you are up against. It takes some reading It's worth it

amp-gauges.shtml


Try wiggling the bulkhead connector parts while the engine is running/ charging and while you are monitoring the "run" wire voltage there under the hood

By the way your MSD "big red" should NOT be hooked to that, if it is so now. The "big red" should be hooked direct to a battery source such as the starter relay stud

The "small red" is a "trigger" wire and should be hooked to the old "run" wire. Now that the ignition is not running directly of the blue "run" wire, there should be very little load on that wire. There is no longer an ignition, nor an alternator field / regulator circuit.

Do you have an electric choke? Check that out for shorts, etc.

What smog equipment is still hooked up under there?

Also, while running / and monitoring the blue wire, "wiggle" the key a bit.

==========================

One last thing.............what is the routing of your cables which supply battery to the starter relay?

Your main big battery cable goes from the battery to "where?"

What jumpers over to the starter relay?
 
the output of the one wire alternator should go to the battery or starter relay stud..

the start and run circuits of the old wiring need to be spliced together then hooked up to the msd small red 12 volt trigger wire.

the one wire alternator has it own regulator on the alternator...your amp meter gauge will not longer work....get a volt meter gauge...
 
70aarcuda, you're talking about taking the ballast out of the loop, splicing it together. 67dart273, I always connect the msd directly to the battery. Car is efi which creates a new set of problems. The factory that connected to the alternator, it's just disconnected. I have an gauge direct to battery from alternator. Will wiggle bulk head wires tomorrow. Thanks for all the input
 
yes..you do not need or want to use the ballast restrictor with the msd box..

one side of the ballast is ignition 1..the other side is ignition 2....which are start and run...

went you hit the starter ..the coil get it 12 volts from the start side...went the key goes to run...the coil gets the voltage from the other side of the ballast which is around 9 volts to key the coil from over heating.....

you splice those to wire together...so the msd sees the 12 volts on both start and run...and then the ballast is not used..
 
70aarcuda said:
yes..you do not need or want to use the ballast restrictor with the msd box..

one side of the ballast is ignition 1..the other side is ignition 2....which are start and run...

went you hit the starter ..the coil get it 12 volts from the start side...went the key goes to run...the coil gets the voltage from the other side of the ballast which is around 9 volts to key the coil from over heating.....

you splice those to wire together...so the msd sees the 12 volts on both start and run...and then the ballast is not used..
Click to expand...

I assumed this was done, and "yes"
 
70aarcuda said:
yes..you do not need or want to use the ballast restrictor with the msd box..

one side of the ballast is ignition 1..the other side is ignition 2....which are start and run...

went you hit the starter ..the coil get it 12 volts from the start side...went the key goes to run...the coil gets the voltage from the other side of the ballast which is around 9 volts to key the coil from over heating.....

you splice those to wire together...so the msd sees the 12 volts on both start and run...and then the ballast is not used..
Click to expand...

So your saying that if i connect both wires that go into the ballast resistor together (basically bypassing the resistor) that will give me a solid switched 12v source for my MSD box?
 
charger426 said:
So your saying that if i connect both wires that go into the ballast resistor together (basically bypassing the resistor) that will give me a solid switched 12v source for my MSD box?
Click to expand...

Yes, here's the thing

The "run" wire and the brown "bypass circuit" (known as IGN1 and IGN2) come from the ignition switch.

The blue "run" wire GOES DEAD during the time the key is twisted to "start."

The brown bypass / IGN2 originally hooked to the coil side of the ballast and supplied full battery voltage to the coil during start/ cranking.
 
67Dart273 said:
Yes, here's the thing

The "run" wire and the brown "bypass circuit" (known as IGN1 and IGN2) come from the ignition switch.

The blue "run" wire GOES DEAD during the time the key is twisted to "start."

The brown bypass / IGN2 originally hooked to the coil side of the ballast and supplied full battery voltage to the coil during start/ cranking.
Click to expand...

I'll give this a shot tonight. When I went to install my MSD box I tried hooking it up to both the wires going into the ballast resistor separately. So when I cranked the voltage dropped and the MSD wouldn't start. I ended up taking the coil + and using that for my switched 12v. This of course left the ballast in line.

Just so I'm 100% clear before I do something stupid. I unplug both sides of my 2 post ballast resistor. Wire them together with the switched 12v for the MSD box. Right? I'm changing the motor out this weekend so I'm sure I'm over thinking everything at this point.
 
100 amp alternator and an 8 gauge wire?

Where is your battery located. In the engine bay or trunk?
 
Battery is in the engine bay. Tying the run start together fixed the fluctuations in voltage. Constant 12+ volts. The ignition is solid. My efi on the other hand has problems totally unrelated to a one wire alternator. Thanks for the help. When I was trouble shooting wiring, this was the only problem I could find.
 
crackedback said:
100 amp alternator and an 8 gauge wire?

Where is your battery located. In the engine bay or trunk?
Click to expand...

If it`s in the trunk, should the alt. wire be ran all the way back to the battery ? I have a chevy 1 wire, 130 amp alt. on mine w/ the ford relay on the firewall, and just ran it to there. Not proven , but seems right now that the battery slowly loses charge, even tho the handheld (fast 2.0 f.i.) says 14.2 what little time I have run it. Been in the paint shop all summer and just now starting to put trim and stuff back on.-------all comments welcome-----bob
 
You must log in or register to reply here.
-

Back
Top