Alt. guage discharging all the time???

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73SlantSwinger

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73 slant six swinger, noticed over the last few days the alt. guage is always discharging. All accessories off, no lights on, etc and the damn guage is still to the left of center. If i turn the fan on with lights or turn signals, it is almost all the way left on the guage. Only started a few days ago....weird. Any idea's?
 
The very quick check is to unhook the green field wire at the alternator and ground that field terminal on the alternator. See if it charges.

If not, be sure that there is power on the blue field lead with key "in run." If so, you should be able to hook/ unhook the temporary ground on the other field terminal and see a small spark in low light.

If it won't charge, likely a bad alternator.
 
If the previous suggestions do not work, check the leads to the Ammeter gauge. The black lead goes closest to the outside of the car. Since the gauge measures current flow, it doesn't really matter to the gauge which lead is which it terms of rendering a reading. However, for the reading to correspond with the label on the gauge, in this case, it is necessary to have the correct polarity on the gauge leads. As you're looking at the gauge from the driver's seat, black wire goes on left post, red wire on right.

If the gauge should fail, the car will start but dies as soon as the key is released into the run position. If that should happen and you still need to use the car, put both wires on one of the ammeter posts, by-passing the ammeter.
 
On mopars with the direct wired ammeter a simple check is to just remove the positive battery cable from the battery while the car is running. If it dies you have a charging problem. If it doesn't your charging system is producing output.
 
Pulling and putting the positive battery cable is a very old school shade tree move.
This can kill all sorts of electronics including voltage regulators.
 
73SlantSwinger said:
ran a few tests with nothing,....
Click to expand...

What exactly did you check and what were the results?


73SlantSwinger said:
unplugged the positive side battery cable and it shut off immediately.....
Click to expand...

I WISH there was a way I could get out and kill this rumor. This so called test proves NOTHING, and as Red said, it's dangerous for modern electronics.

Here's what you need to figure out:

1--Is it the alternator

2--Is it the regulator

3--Is it a wiring problem in the field circuit

4--Is it a wiring problem in the charging path/ output circuit
 
drove the car to work yesterday with no prob. except the car's idle being a little low and the volt guage being on the discharge side the whole time. Later in the afternoon tried to start and it would just click, nada. Had someone jump me off and got it home, put it in the garage and noticed the car was running like crap, idle was barely 500rpms, revved it a few times and noticed it had a bad miss, ended up just shutting it off, then tried to re-start, dead, just clicking.
 
I'd clean the battery terminals and replace the voltage regulator, used to always drive old mopars for a daily driver back in the 1980's.

Carried a good used voltage reg in my car tool box all the time, along with a extra electronic ignition box
 
You've learned that it wont run right on low voltage.
Years ago we had a 93 Lebaron that had lost a brush in the alternator.
It would start and idle on the battery alone. Turn the headlights on and the engine would stop. I did manage to drive it home in pouring rain ( without the lights or wipers ). The brake lights alone would cause it to skip.
 
73SlantSwinger said:
........... no prob. except ..........and the volt guage being on the discharge side the whole time.......... tried to start and it would just click, the car was running like crap,..................
Click to expand...

Have you bothered to read anything posted here?

You still have not answered any questions as to what you have done or checked.

You don't have a "volt gauge." You have an AMMETER
 
ok pulled the alternator and took it down to advance auto, tested out fine on the machine, picked up a voltage reg. while i was there since it was cheap enough and mine looked pretty rough. Came home and put the alternator back on along with the new volt reg, went to fire it up and nothing but clicking. Tested the battery with the terminals off of it and it had 12.4ish volts. Kept randomly checking it over a period of about 30 min. and it was steadily discharging with no terminals hooked up. Took it up to the store and it tested bad so i replaced it. I get the new one back home, hook everything up, turn the key to the on position and same thing, moves to the left of center discharging. Car did fire right up but everytime i either depressed the brake pedal, turned lights on, etc it would discharge almost all the way to the left. Could the alternator be bad even though it was checked? it looks old, part number 7509, a reman from advance from previous owner.....
 
last thing i did was put a voltmeter on the new battery, with the car off got 12.6v. Fired it up, tested again and got 12.3v. Shouldn't my reading be in the 14.0 range if the alternator is charging properly?
 
had same problem with mine. After doing everything you did, I straight wired the amp meter ammeter?? through the firewall connection. Took my dremel and drilled a hole where the two ammeter wires went through firewall connection. Ran new wire straight through firewall and spliced into old wires with connectors. Problem solved. Just ended up being a bad connection at firewall.
Like I said, did everything you did- replaced alt, volt reg, put in extra grounds, new battery, etc etc. "Bypassed" firewall connectors and now everything works. By taking out old connectors at bulk connection and drilling through plastic, looks somewhat original and clean. Took about an hour of taking my time.
 
Sounds like you own a multimeter, so why not try the simple things that 67Dart273 suggested (our patient electrical expert)? Measure across the 2 field terminals on the alternator, with the engine running. 0 V is a command from the Vreg "give no output current" and 12 V is "give full output current". The Vreg responds to the voltage it senses, which is from its blue lead to its case (gnd), so measure what it sees. It may have a bad ground or not getting ignition power, or its output signal (green) is not getting over to the alternator.
 
I had a 65 Valiant (one of my many) that must have come from the factory screwed up. Ammeter was reversed? when charging it would show discharge and vise versa. after many days of trying to figure it out i learned to live with it. Never had charging problem but was weird when seeing the gauge read discharge all the time. I'm sure this is not your problem but just saying. Somebody at chrysler must have been having a bad day that day
 
I had the same issue on my '69 dart. It all came down to a frayed wire on the engine side of the bulkhead connector. I just resoldered the wire to the connector, plugged it back in and voila! Fully running and charging system again. Good luck.
 
Got a question?
I bypassed the ammeter and connected the alternator straight to the starter relay with a fusible link. When I check the voltage to the battery its at 16 volts. It should be at 13 to 14 I believe. How do i resolve the overcharging? (New Alternator,regulators,cleaned wires,cleaned bulk head,cleaned ammeter connection etc. still did not charge thats why I bypassed the wiring)
 
ok update: when measuring across the two field terminals we were getting only around 8.8v with the engine running.
"If not, be sure that there is power on the blue field lead with key "in run." If so, you should be able to hook/ unhook the temporary ground on the other field terminal and see a small spark in low light." Did that and saw the spark.
Went ahead and replaced the alternator today just to rule that out, went to turn the key and same thing, discharge! Fired it off and same thing, constant discharge. I guess i will start looking at electrical connections.....
 
went out searching for a frayed wire or loose connection in the engine bay and under the dash and found a wire completely frayed coming out of the tan connector behind the valve cover, the lead was inside the connector but wire was toast, curious if this has something to do with my problem......
 
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