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Re: Too Much Voltage [Re: dart4forte] #2715800
11/14/19 04:58 PM
11/14/19 04:58 PM
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mopars4ever Offline
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I was getting really erratic reading when i had my issue. I thought I fixed it only to find out a day later mine was overcharging again. I guess where the blue wire was grounding out it must have become ungrounded for a short period of time then regrounded itself. It drove me crazy. Best thing is to look at the wires at the base of the column and trace some of the wires back to see if you see any signs of melted wire. Also any wires in the engine compartment. It becomes pretty obvious once they start to melt.

Re: Too Much Voltage [Re: mopars4ever] #2715886
11/14/19 08:10 PM
11/14/19 08:10 PM
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Mesa, Arizona
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dart4forte Offline OP
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Checked the bulkhead connections, all are snapped in tight. Checked both + and - connections on the coil, both appear to be good. Checked connections under the dash, all seem to be secure. I had the voltmeter + wire attached to one of the ignition wire going into the ballast resistor. Since there’s two wires, top and bottom of the BR I’m not sure I have it connected correctly. The voltmeter still fluctuates like the turn signal is on.


“So if it’s on the internet it must be true”

Abe Lincoln
Re: Too Much Voltage [Re: dart4forte] #2715891
11/14/19 08:21 PM
11/14/19 08:21 PM
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BTW, I ruined a red top optima from the overcharging.

Re: Too Much Voltage [Re: dart4forte] #2715927
11/14/19 09:23 PM
11/14/19 09:23 PM
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax Offline
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Originally Posted by dart4forte
Checked the bulkhead connections, all are snapped in tight. Checked both + and - connections on the coil, both appear to be good. Checked connections under the dash, all seem to be secure. I had the voltmeter + wire attached to one of the ignition wire going into the ballast resistor. Since there’s two wires, top and bottom of the BR I’m not sure I have it connected correctly. The voltmeter still fluctuates like the turn signal is on.


Really, Andrew's methodology to troubleshooting was good advice.
The voltmeter fluctuating may or may not be a problem. If its stablizes when just above idle, certainly by 1250 rpm, then it could be normal.
But if there is a difference in the voltage between the alternator output terminal and the regulator's input, that is a big clue there is resistance in the circuitry.
If it the difference increases with lights or other accessories on, then the resistance is in the shared line. The most likely locations of the resistance are in the connectors. A hand hand voltmeter will reveal where the resistance is causing voltage to drop when current goes through them. (When no current is flowing, then the resistance is zero and there is no voltage drop.)
This same technique can also be used to identify resistance in the return (ground connections).

The fact that the plastic coveres are locked together is good, but does not guarentee the terminals inside are making good contact.
The terminals may have backed out when a connector was removed and reinstalled;
or the contact surfaces may have become oxidized, corroded, or burnt;
or the wire strands crimped to the terminal may have become broken, oxidized, corroded or worked loose from crimp.

Being a '74 truck, I would expect it to have been equiped with a dual ballast resistor. But regardless, the feed wires when running will be at, or close to the same voltage as the alternator output terminal (big stud). The coil connection while running will be something less, as will the ECU connection if its still a true 5 pin ECU.
Usually the 'run' or 'ignition 1' wires are dark blue, and dark blue with stripe.
Usually the 'start' or ignition 2 feed to the coil side of the resistor is brown.
But as the '79 truck diagram in the other thread shows, at some point the ignition wire color scheme was changed.,

Re: Too Much Voltage [Re: mopars4ever] #2715929
11/14/19 09:35 PM
11/14/19 09:35 PM
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax Offline
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Originally Posted by mopars4ever
BTW, I ruined a red top optima from the overcharging.

One of the downsides of any absorbed mat type battery. frown

When I ran the battery down by leaving the parking lights on, and needed a jump start, I watched the ammeter like a hawk. I kept the rpms to a minimum and added headlights and heater fan as needed to suck off some of the power on the uphills.
Even doing that, the battery got quite hot, and I'm sure its not as good as was before.
I also think that contributed to the early death of that alternator.
About a year later the alternator wsan't producing as much power as I thought it should (noticble at low rpm).
Checking it out on the bench revealed one of the stator windings was open. frown
Broke at the Y.
While looking for a replacement stator came across this alternator tag.
https://www.forabodiesonly.com/mopar/threads/charging-battery-with-alternator-warning.424783/
work

Re: Too Much Voltage [Re: Mattax] #2715931
11/14/19 09:36 PM
11/14/19 09:36 PM
Joined: Feb 2003
Posts: 16,117
Mesa, Arizona
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dart4forte Offline OP
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Originally Posted by Mattax
Originally Posted by dart4forte
Checked the bulkhead connections, all are snapped in tight. Checked both + and - connections on the coil, both appear to be good. Checked connections under the dash, all seem to be secure. I had the voltmeter + wire attached to one of the ignition wire going into the ballast resistor. Since there’s two wires, top and bottom of the BR I’m not sure I have it connected correctly. The voltmeter still fluctuates like the turn signal is on.


Really, Andrew's methodology to troubleshooting was good advice.
The voltmeter fluctuating may or may not be a problem. If its stablizes when just above idle, certainly by 1250 rpm, then it could be normal.
But if there is a difference in the voltage between the alternator output terminal and the regulator's input, that is a big clue there is resistance in the circuitry.
If it the difference increases with lights or other accessories on, then the resistance is in the shared line. The most likely locations of the resistance are in the connectors. A hand hand voltmeter will reveal where the resistance is causing voltage to drop when current goes through them. (When no current is flowing, then the resistance is zero and there is no voltage drop.)
This same technique can also be used to identify resistance in the return (ground connections).

The fact that the plastic coveres are locked together is good, but does not guarentee the terminals inside are making good contact.
The terminals may have backed out when a connector was removed and reinstalled;
or the contact surfaces may have become oxidized, corroded, or burnt;
or the wire strands crimped to the terminal may have become broken, oxidized, corroded or worked loose from crimp.

Being a '74 truck, I would expect it to have been equiped with a dual ballast resistor. But regardless, the feed wires when running will be at, or close to the same voltage as the alternator output terminal (big stud). The coil connection while running will be something less, as will the ECU connection if its still a true 5 pin ECU.
Usually the 'run' or 'ignition 1' wires are dark blue, and dark blue with stripe.
Usually the 'start' or ignition 2 feed to the coil side of the resistor is brown.
But as the '79 truck diagram in the other thread shows, at some point the ignition wire color scheme was changed.,



The bulkhead connector was soaked in a rust dissolver, rinsed and blown dry. Same done to the engine side. If done this before. The ballast connections are two red wires on top. Verified with my voltmeter. The run side shows power an no power when the truck is shut off. The feed into the BR doesn’t show power unless the key is in the on position.


“So if it’s on the internet it must be true”

Abe Lincoln
Re: Too Much Voltage [Re: mopars4ever] #2715978
11/14/19 11:56 PM
11/14/19 11:56 PM
Joined: Mar 2006
Posts: 9,791
MI, usa
dvw Online content
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dvw  Online Content
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Joined: Mar 2006
Posts: 9,791
MI, usa
Proper way to voltage drop test. Hot side; connect the dvom to the battery positive terminal. with the engine running take the other lead and follow each positive alternator connection. Any voltage read on the meter is the amount lost at that connection/wire. Battery? You can do the same with the ground side. Negative post all the way to the alternator case.
This test can be used while varying loads, lights, heater ETC. It'll show up the weak spots quickly.
Doug

Re: Too Much Voltage [Re: dvw] #2716233
11/15/19 09:45 PM
11/15/19 09:45 PM
Joined: Feb 2003
Posts: 16,117
Mesa, Arizona
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dart4forte Offline OP
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So, now that I have the charging issue pretty much figured out the truck now dies when put in drive. Truck idles noramally however when put in drive from park or neutral it sputters then dies. Going to Good Guys tomorrow so I’ll tackle that issue next week.


“So if it’s on the internet it must be true”

Abe Lincoln
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