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Discussion Starter #1
hi all, ive been lurking on these boards for a long time, due to my slew of mopars past and present. i love the boards and info on allpar.
let me preface by saying ive combed the internet and these forums before i took the plunge and asked here, and im stumped and in need of guidance.
the vehicle is a 93 landau, v6, 107000 miles. it was old lady owned all its life until my SIL bought it about 3 years ago with 88000 miles on it. she drove it til the driver door started falling off, and she bought a new car. it sat at my house for 4 months untouched, and i resurected it to use as work transport (read: beater) because it has a/c, where as my 01 neon did not. i fixed the door and charged the a/c, and enjoyed it for 3 weeks, until last week.
on the way home i noticed the "check gauges " light flashing, and saw the voltage had dropped below 12, swinging toward 10 at a red light. i turned off the radio (mild amp and subs, btw) and it came back up some, and when the light went green it went back above the 12 mark. i continued to drive it home, about 30 miles, thinking the battery was going bad, which seemed right, because it had sat for a 4 months and the battery was probably old anyway. went to autozone, they tested the battery and reccomended it be replaced, so i did. the new battery didnt "fix" the problem, it still flashed the check gauges light. had the counter monkey come back out with the handheld check box they use, and the new battery tested fine, but said the voltage regulator was bad. i knew from past mopar experience about the computer controlled VR, so i went home and did some checking with the volt meter. battery across terminals shows 13.4, voltage at alternator b+ shows the same, and the field wires also checked out. all grounds (that i know of) also checked out for continuity. i even tried to wire in an external VR per the many FAQs and walkthroughs on this and other forums, which also did not affect the "check gauges" warning, although it did start to overcharge for a brief second when first started it up.
so then i removed the alt. and had it bench tested, it check out as good. went back to reading about bad brushes and burned out diodes, and false "good" tests on parts store equipment... so today i bit the bullet and bought a remanufactured Denso alt and new serpentine belt, along with running a new ground from the battery to the alt, since i managed to break the lug off the factory alternator harness.( it broke off with very little force, so i though it may have been weak to begin with) i also ran a new ground wire from the firewall to the other lug on the alternator, just to be safe. both of these are 10ga wire, with soldered ring terminals. after installing all of that, i crossed my fingers and fired the car up... and found it still doing the same thing, with the "check gauges" light.
now heres the thing, the battery still shows 13.2 or so volts, even after driving it around for 20 mins with the problem. when the car is moving, it seems to be charging, even with all the accesories running (a/c on high, headlights, defroster) it stays right at 12 volts on the gauge. when i come to a stop, it dips to the 10-11 volt area and keeps going slowly down. the car however, does not seem to run differently, and the blower only slows slightly. since im doing this in daylight so far, i can not tell if the headlights/dash dims at all.
after the new parts test drive i checked the voltage again, batt is at 13.2 with car running, alt. B+ is at 13.2. the battery terminals look good, and test good with the volt meter, at the terminals and by poking the VOM leads into the wires downstream of the battery, so i dont think it could be the terminals.

i am stumped. ive been my own mechanic since i was 16 (im 37 now) and as stated before ive have a bunch of mopars and other cars and have never ran into anything like this before. very sorry for the long first post, and if i get this beast functioning properly i promise ill contribute more, im just stressed and strung out the past two weeks from trying to work a full time job (at 55 hours a week, i drive a semi for a living) and repair this car afterwards in my limited free time. thanks in advance.

cliff notes: car charging funny, replace battery and alternator and two main ground wires, still getting low voltage.

oh, btw, the amps are disconnected through all of this, and the stereo face is removed, so it shouldnt have any power except the memory circuit going to it.
 

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I wouldn't necessarily trust the gauge. Get a couple of long leads for your multimeter, put them on the battery, run them up under the hood and under the windshield wiper, and replicate the conditions. That way, you'll have actual voltage numbers instead of tick marks to to by.

By the way, welcome to the forums!
 

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Discussion Starter #3
Thanks for the welcome!
After I wrote the post last night, it had gotten darker, so I went out and ran the car to see if the dash/headlights dimmed. They did, but not much. My 01 neon has an underdrive pulley and it does about the same thing under heavy accessory load (I.e. driving to work in the predawn hours in the rain, running headlights, wipers and blower for defogger)
I will be checking driving arojnd voltage with the meter tonight, I will check back in after that.

One more thought, is it viable to drive like this? Provided its a "real" problem I haven't figured out yet and not a bad gauge? The battery seems to stay at 13.2 volts, after a weeks worth of messing with it, starting and driving around the neighborhood. The alt has to be charging some, right?
Forgot to add, there are no codes thrown either, save for the " battery has been disconnected recently" one that is stored, CEL is not on at all.
 

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I wouldn't be surprised at all if the circuit that triggers that light is bad or there's something wrong with the voltmeter. My light doesn't seem to trigger at that level. It seems to me that the alternator output voltage is toward the low side of what it should be, but it's ever so slight and shouldn't make a difference. When you mentioned the bit about the headlights, do you mean that you stopped the car and checked them?
The alternator usually can recharge a slightly-flat battery after a good bit of highway driving. At idle, current output decreases, but the fuel pump, for example, draws the exact same amount of current as it does at 60 MPH. The alternator has less spare current to charge the battery with, and so it charges much slower, if at all. As the engine RPM (i.e. vehicle speed) increases, the alternator current does as well, and the battery charges faster. Sporadic, local trips may actually break even depending on electrical use and how many times the engine is started. Since your voltage isn't dropping when the car is sitting, I think we can rule out excessive IOD or a short.
Disconnecting the battery erases any codes that may be present. They won't come back right away, in some cases. Try to avoid disconnecting the battery for a couple weeks to see if the computer finds anything wrong.
One thing that you never mentioned was if you tested the alternator field terminals. There should be a test procedure in an FSM. I doubt this is the problem, but check it anyway.
 

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i also ran a new ground wire from the firewall to the other lug on the alternator, just to be safe.
This may contribute to the issue. First, the firewall may be at a slightly different potential from the engine block or the left fenderwell, both of which have battery grounds. Second, if you left the original ground wire intact, an additional ground wire that connects to a different place will likely set up a ground loop. This means that the two wires will not be at the same potential, and a current will flow between them, and cause an offset voltage. If the original ground wire is OK, I'd remove the new one.

Good idea to check the field terminals as suggested.
 

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Discussion Starter #6
Visual inspection of the field terminals and wires checked out good, and with the new alternator the running charging voltages are within spec.

The new primary ground was ran because the ground lug on the molded plastic alternator harness snapped of. It is ran directly to the battery, the same as the original ground (which is now not grounding anything)

The difference in potential theory is a new one to me, however, the "new" ground wire I ran is tied into the engine ground strap at the firewall, I didn't tie into a different or new spot on said firewall.
 

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I would do an electrical inspection of the field terminals and harness as well. Electronics can often look fine but really have issues.
 

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Devil Anse said:
The difference in potential theory is a new one to me, however, the "new" ground wire I ran is tied into the engine ground strap at the firewall, I didn't tie into a different or new spot on said firewall.
Yes, you did. Because the alternator housing was not grounded to the firewall. Now it is. The firewall can be at a slightly different potential from the battery post, depending on the condition of the existing connections.

+1 on checking the field terminals electrically. Visual means nothing. I had intermittent field connections that LOOKED fine, but were causing low output.
 

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Discussion Starter #9
Is the alternator case not grounded by the alternator braket, which in turn is grounded to the engine, which uses the ground strap i have tied into?

Reguardless, the car is behaving the exact same as it was before and after the extra ground. I will remove it tonight and report back.
The field wires appear good both visually and with a voltmeter. I dont remember the exact readings, but when I was testing I had the numbers in front of me and they did fall within spec according to the source, I believe it was a MiniMopar page.
 

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Did you get a chance to do the test with the multimeter? I think that's where you're going to find your issue
 

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Discussion Starter #13
ImperialCrown said:
The alternator ground also relies on the bell-housing-to-battery (-) cable and the body-to-battery (-) cable for a good ground.
Hmmmm... this intrigues me. Did a search for other cars that use the same engine/ecu, and found a thread about a 93 caravan with the same issues as my lebaron, and the engine to batt (-) cable had been moved to the firewall, whereupon it rusted loose. Cable was cleaned up and returned to its proper location and the problem was resolved. I will be checking this also tonight, anyone have any pointers as to where I should look? Obviously follow the cable from the battery, but its a nest of wire loom and age, it can be difficult...
 

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The negative battery post connects to three places - the alternator, the cylinder block and the left fenderwell (the thinnest wire of the three). The left fenderwell connection might only be reached by removing the battery, as it's sort of buried near where the ECM bolts in. All of these connections should be undone and cleaned, whether or not they look OK.
 

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Discussion Starter #15
ok, update: i found, and cleaned both the engine block ground and the left fenderwell ground. the fenderwell ground was pretty gnarly, had to remove the bolt with vice grips from rust/corrosion. i reinstalled with a new self tapper screw and sanded both the ring terminals and the fender area down to shiny metal, did the sanding bit on the engine block ground also.
fired the car up after that, and it is still doing the gauge bounce/check gauges light. so i hooked the multimeter up to to the battery and took it for a drive. the lowest the voltage went was 12.1, sitting at a red light with the a/c running full blast, the headlights on, the radio (with subs and amp) on and turned up. the highest it went was 13.8, running all the things mentioned, cruising and the engine turning 2100 rpm or so. 13.8 is acceptable range, right? it never went over that...

so, maybe bad/sensative gauge? as i mentioned before, my 01 neon with an underdrive pulley and a legit 1200 watt stereo system (rockford fosgate power numbers, not walmart equipment "maxx powah" numbers, everything was run on 4 gauge power wire) would do the same thing with the stereo going and the lights on, and it runs/starts charges fine, and has done so for 12 years.

basically, my conclusion is this ol girl is fine to drive, and i will just keep an eye on her... whats the board opinion?

and thanks for the tip on finding the grounds, Bob Lincoln.
 

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13.8V is good; dropping that much at idle with accessories on is not. Still suggests a bad connection. Did you clean the battery posts and clamps with a wire brush? And inspect the cables where the insulation meets the clamps, for corrosion up under the insulation (if the insulation has split?)?
 

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Discussion Starter #17
Battery is brand new, terminals were cleaned when new batt was installed. The wires/insulation are not split, but they are kind of brittle at the terminals, nothing bad enough to ring an alarm bell, but possibly enough to hide something deeper. No wire is exposed at the terminal either, unless I dig at it (like I have done with the multimeter probes)
I'm going to replace the terminals in the next few days, provided I can find a local source for good terminals, not the parts store bandaid fix garbage.
 

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If the terminals check out, multimeter it and turn the accessories off one by one to see which gives you the biggest jump in voltage. The radiator fan(s) could have a motor that's drawing more current than it should. 12.1 still seems high to have that light triggering...
 

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The Imperial does almost the same thing... in my case, I've narrowed it down to the variable displacement AC compressor. The engine bogs down on a hot day when that thing is running wide open and trying to cool down the interior and I come to stop signs. But when the interior is cool, it doesn't do that. It also doesn't do it at idle.

I figure when I found that leak at the low side valve a couple years ago, it was just a hair too late for the compressor. It hasn't failed yet after two years, but is obviously no longer acting like a flawlessly working AC compressor. I've been getting by only letting it run the AC sparingly off the highway in really hot weather, but considering that it only shows the problem when the interior is hot I haven't bothered doing anything major about it. One of these days, I'll have to replace the compressor, but considering I still have more than adequate cooling performance I don't know if I really need to bother. It could last another ten years, and by that time I'll either not have the car anymore or have the money to be able to afford to fix it.

And definitely, check all the wiring between the alt and battery. The Imperial had corrosion in the PDC, as well as in the starter cable and just about all cables at the battery. It was a major difference when I fixed all that up.
 

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Discussion Starter #20
Oklahoma Wolf said:
The Imperial does almost the same thing... in my case, I've narrowed it down to the variable displacement AC compressor. The engine bogs down on a hot day when that thing is running wide open and trying to cool down the interior and I come to stop signs. But when the interior is cool, it doesn't do that. It also doesn't do it at idle.

I figure when I found that leak at the low side valve a couple years ago, it was just a hair too late for the compressor. It hasn't failed yet after two years, but is obviously no longer acting like a flawlessly working AC compressor. I've been getting by only letting it run the AC sparingly off the highway in really hot weather, but considering that it only shows the problem when the interior is hot I haven't bothered doing anything major about it. One of these days, I'll have to replace the compressor, but considering I still have more than adequate cooling performance I don't know if I really need to bother. It could last another ten years, and by that time I'll either not have the car anymore or have the money to be able to afford to fix it.

And definitely, check all the wiring between the alt and battery. The Imperial had corrosion in the PDC, as well as in the starter cable and just about all cables at the battery. It was a major difference when I fixed all that up.
This... I ran the car today with no a/c, and the voltage with the other accesories running the volt meter never dropped below 13...a/c on, dropped down to 12.2.
Also, when this car was purchased the a/c did not blow cold, and I never checked it then because it didn't bother my sister in law to not have a/c. When I took possesion of it, I used a can of that A/C Pro stuff they advertise on TV, and it worked. Now obviously it has a leak, because the compressor was not engaging at all before the A/C Pro, so it was pretty clearly dry, if not bone dry.
So, after all this, the downside is I'm out 220 bucks for a battery and alternator, but the upside is I could theoretically get another 100k miles out of the new alt, and won't need a battery for a while either...lol. hopefully I can nurse the current a/c compressor through this hot season and save up time and money to get a new compressor for next summer... fingers crossed!
Thanks for all the help everyone!
 
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