Lights flicker and gauge jumps around???

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74dusterman

74dusterman

74dusterman
Joined
May 4, 2011
Messages
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Location
Minnesota
I am having issues with my Duster. When driving at night the lights constantly flicker lightly and the voltage gauge bounces from 14-16volts constantly. I rewired the entire engine bay with all new wiring. I have a ground from the motor to the body, from the body to the battery, and a wire from the mounting bolt on the voltage regulator to the body. Still didn't cure it. I replaced the amp gauge with a voltage gauge and removed the bulkhead connection at the firewall. I have tried a different voltage regulator. I tried switching the field wires around. I have tried every thing I could think of. I am hoping someone will have an idea that I might have missed so I can drive at night without the damn lights looking like a strobe light. Any idea is appreciated even if it sounds dumb. :banghead::banghead::banghead:
 
Please step up to a 65 amp alt and make sure to have a 10 gauge heavy wire to alt stud feed, make sure belts are tight .
 
I don't want to sound redundant, but make triple sure there isn't any high resistance(i.e bad connections or burnt or too small wire gauge) in the circuit. Next verify you have a known good voltage regulator & it's wired correctly. Also check the alternator doesn't have any open diodes in the rectifier.
You problem is on the regulator side of the system if your getting 16v. A larger alternator won't help. Also don't trust the gauge for your readings, use a meter. (Not saying you didn't, but it wasn't mentioned in the post)
When you say you "removed the bulkhead connector at the firewall" does that mean you bypassed it or removed it & checked it for poor connections? Just asking to get a better idea of what you've done already.
 
How much of your under-dash wiring is factory? This sounds a bit like a failed splice in the ammeter wire. This is the factory splice in the black ammeter wire which feeds off to the headlights, ignition switch, fuse panel, and a couple of other things depending on the year/ model

It's a few inches from the ammeter in the black wire up under the dash. Only way I know to check it is to take some measurements and try to isolate it, then tear into the dash and physically inspect it

If you have not, and sounds like you have, read the MAD article which has a good simplified diagram

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

THANK YOU!!!! for posting relevant information.
 
Thanks for the suggestions. Belts are tight. I don't have the amp meter anymore. I converted the entire dash to aftermarket mechanical gauges and installed a voltage gauge. The article in the post by 67Dart273 is exactly what I did to eliminate the amp gauge and install a volt gauge. Wire from alternator is new 10ga wire. All of the wiring in the engine bay and charging system is brand new. I will check out the alternator and try another voltage regulator.
 
I still haven't remedied the problem yet. I need to try a new alternator yet, haven't had time to work on it.
 
If you had left in the ammeter, you would have a lot more information to go on.
I can't understand why people change out factory designs then wonder why things work poorly.
 
Darthomas said:
If you had left in the ammeter, you would have a lot more information to go on.
I can't understand why people change out factory designs then wonder why things work poorly.
Click to expand...
.
I removed the ammeter because it burned out on me. I didn't feel like getting stranded again so I converted it. The factory did a lot of stupid **** and I have changed a lot of it. I don't recall anywhere in my posts that I asked for anybody's criticism about what I do with my car.
 
Darthomas said:
If you had left in the ammeter, you would have a lot more information to go on.
I can't understand why people change out factory designs then wonder why things work poorly.
Click to expand...

That's because some of the factory designs work poorly.
Especially after all these years.
 
TrailBeast said:
That's because some of the factory designs work poorly.
Especially after all these years.
Click to expand...
Do what you like, but when you do your own engineering, you're also on your own when things don't work as you expect.
Taking care of things and understanding how they are supposed to work is just too difficult, just spray a bunch of new at it, that'll fix EVERYTHING!
 
Darthomas said:
Do what you like, but when you do your own engineering, you're also on your own when things don't work as you expect.
Taking care of things and understanding how they are supposed to work is just too difficult, just spray a bunch of new at it, that'll fix EVERYTHING!
Click to expand...

My car went out of warrantee a long time ago, and believe me I can make things work how I want. :D
There isn't a damn thing difficult about understanding any of it, and that's part of the problem.
I fully understand how it was originally designed and the way it was designed falls short of what I want out of my car, so I change it.
You are just too new here to know me or my car. :D
 
Darthomas said:
Do what you like, but when you do your own engineering, you're also on your own when things don't work as you expect.
Taking care of things and understanding how they are supposed to work is just too difficult, just spray a bunch of new at it, that'll fix EVERYTHING!
Click to expand...
So are you saying that you have a bone stock all original car? You have never upgraded anything on your car? Everything is to factory specs? You must be busy on this forum if you critique every modification people make, engine builds, transmission swaps, rearend swaps, wiring, brakes, ect. People are always changing stuff to improve the reliability, performance, handling, and comfort of their cars. I swapped out the /6 for a 360, swapped the 904 auto for a 833 4 speed, swapped the 7.25 rear end for a 8.75, and rewired pretty much the entire damn car. You got anything you want to say about all of those upgrades I made?
 
I've changed some things, but even then I stick pretty much with factory parts.
I won't try to tell anyone what to do, but I've seen plenty of people who add problems seeking speed over reliability and dependability.
 
Darthomas said:
I've changed some things, but even then I stick pretty much with factory parts.
I won't try to tell anyone what to do, but I've seen plenty of people who add problems seeking speed over reliability and dependability.
Click to expand...
The symptom you describe is very common with mechanical voltage regulators, even new ones, because setting the charge/discharge contacts, spring tension, and gap between the armature pole piece is really tough to get right, and when wrong that's exactly what they do.
I expected your Duster would have an electronic regulator, and I haven't encountered that with the electronic type.
Let's move forward and figure this out.
 
Darthomas said:
The symptom you describe is very common with mechanical voltage regulators, even new ones, because setting the charge/discharge contacts, spring tension, and gap between the armature pole piece is really tough to get right, and when wrong that's exactly what they do.
I expected your Duster would have an electronic regulator, and I haven't encountered that with the electronic type.
Let's move forward and figure this out.
Click to expand...
It is an electronic regulator, standard alternator with 2 field wires, MSD 6al ignition (not sure if that matters) and I completely rewired the engine bay. I haven't had time to try a new alternator or regulator yet, 2 jobs and more important life issues come first.
 
Does it change at all regarding rpm,
or is the variation constant?
Does it change with load on the electrical system, better or worse with headlights, or ni diff?
 
Darthomas said:
Does it change at all regarding rpm,
or is the variation constant?
Does it change with load on the electrical system, better or worse with headlights, or ni diff?
Click to expand...
At idle it is the same both under a load and not. Cruising down the road it does it under a load (headlights on or turn signal on) but when not under a load the gauge sits steady at 14v.
 
Just for yucks, loosen one bolt on that regulator and wrap a wire around the bolt.
Tighten it back down, then put the other end directly to negative post of the battery.
This will take poor grounding out of the list of possible things.
 
How do I check for open diodes in the rectifier? I'm sure I need to take the alternator apart but will it show when tested? I'm having the same issue. I have a new Ron Francis Express fuse box/wiring harness, 1 gauge battery cables, 6 gauge ground from battery to body in 2 places. The fuse box, Ron Francis voltage regulator, are all grounded. Alternator reads 14V and above at idle. At higher rpm it reads 15V. I have checked voltage with a fluke multimeter and have very minuscule voltage drop. For example, at 2500 rpm, I get 15V at the battery terminals and 14.91V using the master cylinder, alternator body or intake manifold as a ground. I'm thinking alternator even though it's new.
 
I am fighting the same thing. Converted to 2 field alternator, electronic regulator and ran a 10 gauge wire to the alternator from the starter relay (battery is in the trunk). I removed the wire from one side of the factory amp gauge and put it on the other terminal effectively using it as a tie point. My voltage is over 15 volts at the alternator. I measured the ground potential difference at the regulator at 0.165 volts. I am suspecting that I may have a leaky or shorted diode in my nice chrome Voltmaster alternator. I will try swapping my factory alternator in when I get back home on Thursday, I will let you know what I find, it might help you.
 
srduster340 said:
How do I check for open diodes in the rectifier? I'm sure I need to take the alternator apart but will it show when tested? I'm having the same issue. I have a new Ron Francis Express fuse box/wiring harness, 1 gauge battery cables, 6 gauge ground from battery to body in 2 places. The fuse box, Ron Francis voltage regulator, are all grounded. Alternator reads 14V and above at idle. At higher rpm it reads 15V. I have checked voltage with a fluke multimeter and have very minuscule voltage drop. For example, at 2500 rpm, I get 15V at the battery terminals and 14.91V using the master cylinder, alternator body or intake manifold as a ground. I'm thinking alternator even though it's new.
Click to expand...
Diodes are easily checkex with a ohmmeter.
There should be a large difference in ohms between the test leads placed one way vs the other. An open diode reads more or less infinite resistance.
For me, the easiest way is just listening to the alternator. If all the diodes are good, there's no humming-whirring sound, because there's very little AC ripple in the three phase after summing into DC.
If one diode is out, you'll start to hear the whirring sound, if two diodes are out, the whirring is unmistakable, and you'll notice the ammeter never goes way over into charge like it should, say like if you left the headlights on for 10 minutes with the engine off, and then went for a drive. Three diodes out, and you'll notice the ammeter hardly goes over into charge at all, and can't even accomodate the headlights at idle in neutral. It will go into the discharge immediately. This is why I love ammeters, for the additional information they provide.
Now, this whirring is not high pitched at idle speeds, it's more like like a hum, about the pitch of the first note in "Happy Birthday to you". It can be heard just as easily in the car as standing in front of the alternator, maybe better. If you have a factory radio, the hum will be quite clear as soon as the radio is turned on with the volume down all the way, and it doesn't get louder with turning the volume up. The hum is AC ripple superimposed on top of the DC level.
If you have an oscilliscope, it sticks out like a sore thumb, you'll see the ripple where the dead diodes didn't fill in the output, and that's the ripple that makes it audible both physically and in the radio's output stage.
 
If no whirring, there's always modern cost cutting stator winding methods, which are called high current, because no one would buy alternators honestly marketed as
"Low Voltage at Idle Speed".
Proper Stator windings have 12-13 winding loops in each pole, and can be estimated quickly looking at the windings through the slots in the case. If yours has only 6-7 loops per pole, the voltage regulator can send the full voltage to the rotor trying to maximize current flow in the rotor to increase output, and still not create enough to charge at idle rpms.
 
Any shorted diode, and you'll have a dead battery overnight. This doesn't happen often.
 
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