Over charging now, no ballast resistor

[ValiantRacing]

I have an MSD box so i did not need the ballast anymore, i bypass it connecting the wires together, i have a new and battery and voltage reg, but is overcharges so bad the belt on the alternator squeals. do i have a wire going to ballast that is don't need? My other cars i run a denso alt, so i do not have a problem.

 

[MadScientistMat]

Bypassing the ballast resistor won't have much to do with overcharging. Check for the following:

Does the alternator charge with the voltage regulator unplugged? If so, the alternator has an internal short.

Does the voltage regulator see battery voltage at its input, or is there a voltage drop? If there's a voltage drop, check for loose or corroded connections.

Does the voltage regulator have a good ground? It grounds through its mounting screws to the sheet metal. This may need cleaning. Also don't forget the ground cables from the engine to the battery and chassis.

If all that checks out, the voltage regulator is likely suspect. New is not always the same as good.

 

[67Dart273]

Have you measured the running/ charging voltage at the battery? Make CERTAIN that the VR is grounded and that it is wired correctly and getting battery voltage to the blue wire

WHAT year make and model?? More important, what kind of alternator and VR?

Stock pre 70? Stock 70/ later?

Is it possible that the battery is simply way down, or that it is defective?

 

[ValiantRacing]

Have you measured the running/ charging voltage at the battery? Make CERTAIN that the VR is grounded and that it is wired correctly and getting battery voltage to the blue wire

WHAT year make and model?? More important, what kind of alternator and VR?

Stock pre 70? Stock 70/ later?

Is it possible that the battery is simply way down, or that it is defective?

Car is a 72 Scamp, made sure battery is fully charged, i did add an extra ground wire to the VR, i will check the blue wire, i was thinking the VR is bad, but i also wanted to cover everything.

Anybody have a suggestion for a good VR? i have a Napa one now.

 

[67Dart273]

First check that the brush holders are not damaged, AKA that the VR has control. Start and run, confirm that it is overcharging. As I said check the charging/ running battery voltage

Now, pull off the VR connector. Should stop charging. if not, pull off the green wire at the alternator. Should stop charging.

Next, check for the "voltage drop" problem. Locate a voltage source in the key switched "ignition run" IGN1, dark blue line. The ballast would have been a good place. For now you can use the blue wire at the alternator field. Do NOT disconnect anythiing. Backprobe the connector. With the key in "run" and engine stopped, stab one meter probe into the top of the battery positive post, and the other on the blue wire terminal. You are hoping for a very low reading, the lower the better. Over .4V or so you need to find out. If this is causing the problem you are seeing, the reading is likely going to be 2V or more.

Make CERTAIN the VR is grounded.

Check the VR connector for corrosion in the terminals with a flashlight. "Work" the connector in/ out several times to scrub the terminals and "feel" for tightness.

"Some" .17 (Winchester or Hornandy) caliber rifle cleaning brushes will fit the female of those terminals, and of the popular flat trailer connnectors.

If those tests are OK, either the VR is not grounded, or the VR is bad.

If all this seems OK, the VR is likely bad.

 

[ValiantRacing]

First check that the brush holders are not damaged, AKA that the VR has control. Start and run, confirm that it is overcharging. As I said check the charging/ running battery voltage

Now, pull off the VR connector. Should stop charging. if not, pull off the green wire at the alternator. Should stop charging.

Next, check for the "voltage drop" problem. Locate a voltage source in the key switched "ignition run" IGN1, dark blue line. The ballast would have been a good place. For now you can use the blue wire at the alternator field. Do NOT disconnect anythiing. Backprobe the connector. With the key in "run" and engine stopped, stab one meter probe into the top of the battery positive post, and the other on the blue wire terminal. You are hoping for a very low reading, the lower the better. Over .4V or so you need to find out. If this is causing the problem you are seeing, the reading is likely going to be 2V or more.

Make CERTAIN the VR is grounded.

Check the VR connector for corrosion in the terminals with a flashlight. "Work" the connector in/ out several times to scrub the terminals and "feel" for tightness.

"Some" .177 caliber rifle cleaning brushes will fit the female of those terminals, and of the popular flat trailer connnectors.

If those tests are OK, either the VR is not grounded, or the VR is bad.

If all this seems OK, the VR is likely bad.

Thank you i will check all of that.

 

[Oldmanmopar]

If the blue wire going to the voltage regulator shows low voltage will make it overcharge. It comes from the ignition switch to the bulk head

Then from the bulk head it goes to a soldered 4 way connection in the harness. From there it splits goes to the Alternator, voltage regulator, ballast resister, electric choke, Somewhere that wire is shorted or has a bad connection.

I usually find it is at the bulk head being dirty but there has been times I found the soldered joint at the splice is broke. I believe if you find your Alternator and voltage regulator are good it will be that wire.

Get a volt meter and check power from the ign. to the splice and out to its use under the hood to find where it is losing power from a short or broken. CHECK THE BULK HEAD CONNECTION.

 

[MadScientistMat]

Anybody have a suggestion for a good VR? i have a Napa one now.

I've seen enough complaints about different brands that I decided to make my own. It will take about a month before they're ready to ship, so if you determine your regulator is broken and need a replacement now, there are a few NOS ones out there at reasonable prices.

 

[67Dart273]

If the blue wire going to the voltage regulator shows low voltage will make it overcharge. It comes from the ignition switch to the bulk head

Then from the bulk head it goes to a soldered 4 way connection in the harness. From there it splits goes to the Alternator, voltage regulator, ballast resister, electric choke, Somewhere that wire is shorted or has a bad connection.

I usually find it is at the bulk head being dirty but there has been times I found the soldered joint at the splice is broke. I believe if you find your Alternator and voltage regulator are good it will be that wire.

Get a volt meter and check power from the ign. to the splice and out to its use under the hood to find where it is losing power from a short or broken. CHECK THE BULK HEAD CONNECTION.

Hi, Steve. I've posted this a zkillion times. It can be any terminal, crimp, connector, connecton, including the contacts in the ignition switch itself, and they add up if more than one, in the complete path from the battery to the VR IGN termnal

Generally (factory wiring) the path starts at the battery, to the starter relay "big stud," through the fuse link (LARGE RED) From then the problems can be: the LARGE RED going through the BULKHEAD CONNECTOR, to the AMMETER, including the wire end terminals, the ammeter itself, out of ammeter on the LARGE BLACK, to the WELDED SPLICE which fails rarely but can fail, to the IGNITION SWITCH CONNECTOR, through the switch itself, back out on the DARK BLUE ignition run, back out through the BULKHEAD CONNECTOR, and to the ballast and at some point a splice to split the blue off to whatever loads it feeds, including the ignition system, VR ign terminal and the blue field wire at the alternator.

 

[67Dart273]

WHY DOES THIS AFFECT MOPAR the way it does? Because Mopar is THE ONLY manufacturer who (to my immediate knowledge) who used the VR POWER terminal, connected of course to a POWER circuit (ignition run) to obtain VOLTAGE SENSING for the regulator. Both GM and Ford, and the AMC stuff that used Motorola, have a SEPARATE dedicated sense wire off the VR. There is no/ very little current in that "sense" wire circuit, so there is no or very very little voltage drop.

WHAT causes drop and WHY does it matter to the VR?

Voltage drop is caused by current flow, and generally the more current in a circuit, the more drop. For example, you might have some drop but tolerable in the tail/ stop/ turn circuit of some vehicle, but when you add a trailer with numerous clearance and tail/ turn lamps, that extra load increases the voltage drop, whatever it might be.

The drop in the ignition harness--or in some cases the VR ground circuit, makes the VR "see" lower voltage so it "thinks" the battery is low--and ramps up the output of the alternator to satisfy the "sensing" point. Even though the ign terminal of the VR is seeing 14V at that point, the battery, because of the drop, is now at 14V + whatever the amount of the drop is.

THE SIMPLE thing is, the VR MUST SEE battery voltage exactly. Both in regards to the ground circuit and the ign terminal IE the power/ sense terminal.

 

[ValiantRacing]

Thanks for all the help, looks like I have a shorted out alternator, charges with unplugged at VR and with green wire off.