Dart regulating issues

[NoahSewal]

Im having an issue with my 74 dart 318/904 where my alternator will be regulated up until about 2000 rpm. when revved higher it will stop regulating my power and lights will get brighter, the gauge goes up, and everything else is probably getting more power too. I have no clue what it can be because i've changed the regulator twice, regrounded the regulator, messed with the field wires and plugs. it has a 2 field wire alternator with the external regulator. The alternator was bought maybe 8 months ago but wasn't driven all winter. I don't want to drop 50 bucks on an alternator if it's not the issue. anyone have any tests i could do to maybe see if it's a wiring issue or any adjustments that may need to be made to the alternator? TIA

 

[Murray]

This should be a "round back" alternator. Measure voltage across battery while running. Then bypass regulator with a jumper wire, directly connecting its two wires. Voltage should be over 15v. If it is, then your problem is in the regulator.

 

[Joey4speed]

There's quite a few tests that can be performed, there are many threads here handling this issue, just type in "overcharging" in the search bar.
It may help if you let us know the year and model you have, plus if the ignition is points or electronic.
Were there any modifications?

 

[Tooljunkie]

Check body ground to engine as well.
Unless something in alt is grounding regulator side of field. Continuity test of terminal to ground and rev it up.

 

[Dana67Dart]

Im having an issue where my alternator will be regulated up until about 2000 rpm. when revved higher it will stop regulating

Always start help posts with

1. Year
2. Car
3. Engine
4. Trans
5. Modifications
6. Last work done
7. And in this case what alternator (round back, square back 1 field wire or 2)
8. What regulator you have (small with one screw on and one press on connection or larger with triangular connector)

How do you know it is no longer regulating?

Most alternators have more charging ABILITY at higher RPM.

I capitalized ABILITY because like the wires in your house, if you plug in a 25w lamp it works if you plug in a 100w lamp it works, the power company is not over charging your house. They are providing enough power for your needs as needed.

Your alternator and regulator will not over power anything. The voltage might go up higher due to a bad regulator or wiring.

the gauge goes up,

What guage?

If the Ammeter is going from center to the right then you have a lot of electrical load being PULLED by devices or battery

and everything else is probably getting more power too

See above. Power is what a device PULLS not is supplied.

I have no clue what it can be because i've changed the regulator twice, regrounded the regulator, messed with the field wires and plugs

Because you said "wireS" I assume you have an electronic voltage regulator ( larger rectangular box with a triangular connector.)

That also suggests you have a (most likely) square back alternator with 2 field wires (Isolated field)

If your car did not origionally come with this alternator and regulator setup you may have gotten the wrong alternator from the parts store.

Again a lot of guessing because from your first post you could be working on a 65 mustang.

The alternator was bought maybe 8 months ago but wasn't driven all winter. I don't want to drop 50 bucks on an alternator if it's not the issue

Worst case is you pull the alternator (2 bolts and some wires) and bring it to your local parts store and have it tested.

Also most parts stores have testers they can put on your car when it is running.



After you give us the details of your setup we all can be more helpful.

 

[67Dart273]

This should be a "round back" alternator. Measure voltage across battery while running. Then bypass regulator with a jumper wire, directly connecting its two wires. Voltage should be over 15v. If it is, then your problem is in the regulator.

It is not that simple

 

[67Dart273]

You need to check IF the VR is ACTUALLY (electrically) grounded TO THE BATTERY and IF the VR "IGN" terminal is actually at the very same voltage as the battery

And, you need to check this when the problem is occurring IE "rev" the engine up to see if this is so. There are several things you need to check and IN A SPECIFIC WAY

Make these checks with engine warmed up and battery charged as "normal" as it normally runs. VR is temperature sensitive.

1....Ground circuit. Run engine at fast idle, and make this check both with all accessories "off" and again with lights, heater, etc running.
.....Stab one meter probe of your multimeter into the top of the battery NEG post and the other into the mounting flange of the VR. Make sure to stab HARD to get through pain, rust, chrome, etc. You are hoping for a very low reading, the lower the better, and zero is perfect
2.....VR IGN terminal and wiring harness Connect meter as close as you can to VR IGN terminal. This is likely at the ballast resistor, and connect remaining probe to the battery POS terminal. With key in "run" and engine stopped, you are hoping for a very low reading. Over a few tenths of a volt investigate that circuit
3....Since you are having hi RPM problems, "it might be" that if the above (2) is a problem, it may be getting worse, due to a bad connection, at higher RPM. THIS test you will have to do differently.
A......With probes connected as in (2), remeasure with engine running at just above idle or at fast idle. Measure again at "low cruise" AKA simulate running 25-30mph in high gear. Then again with engine revved up above 2K Does this reading change substantially?
B.......With one probe grounded to battery, connect other probe to 12V at ballast. "Key" side, not the coil side. With engine running just above idle, THIS SHOULD show right around 14V if VR is correct, REGARDLESS of battery reading. Now again rev engine up above 2K and see if the reading changes substantially.

What you are trying to do here, is determine
1....If there is voltage drop in the harness at all times
2....If there is substantially more drop at high RPM
3.....If the VR is for some reason acting up at high RPM

 

[67Dart273]

WHAT YEAR IS THE CAR AND WHAT TYPE REGULATOR ARE YOU USING

 

[Dana67Dart]

WHAT YEAR IS THE CAR AND WHAT TYPE REGULATOR ARE YOU USING

That's what I and a couple others have asked.

OP might be working on a 65 mustang for all we know!