Barracuda Challenger Forum

Author Topic: Over charging . alternator  (Read 145 times)

Offline Dale1035

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Over charging . alternator
« on: June 03, 2017 - 07:53:24 pm »
I am having a problem with over charging. So far I have replaced the alternator, voltage regulator and engine wiring harness. Today I checked the voltage at the alternator with the ignition switch in the run position, engine not running. The blue wire checked 10.8 volts and the green wire checked 1.2 volts. I think they should read blue at 12 and green at zero. Any insight as to what is causing the problem is appreciated.

Offline 73_Cuda_4_Me

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Re: Over charging . alternator
« Reply #1 on: June 03, 2017 - 09:15:53 pm »
Double-check and clean battery connections (use dielectric grease on terminals to help prevent corrosion), engine ground from battery, and frame ground to engine at firewall...

I just changed my battery - was charging at 15-15.5 volts all the time, and it was a bad cell in maint-free battery going bad... new battery and charging 13.5-14 now...

1973 Plymouth Cuda BS23H3B567783

R11 V6X EN2
M21 M25 M31 M88 N41 N42
V1X U B41 C56 G37 J54
JY9 A6X9 0 703 501616
E55 D34 BS23 H3B 567783

Offline Chryco Psycho

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Re: Over charging . alternator
« Reply #2 on: June 05, 2017 - 06:56:07 pm »
Normal voltage should be 12.8 - 13.2 not running & up to 14.5 running

Challenger - You`ll wish You Hadn`t

Offline Dale1035

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Re: Over charging . alternator
« Reply #3 on: June 06, 2017 - 11:26:27 am »
Thanks for the replies. I have had the Alt. checked and the battery. and they are fine. I am now in the process of removing the dash harness and ignition switch to check for a burnt wire or connection. Last summer the voltage regulator went out and charged the battery to 16 volts. I had to replace 5 fuses and the radio. So I'm checking to see if anything else was damaged. I have already replaced the dash harness because of a burnt connection.

Offline 734406pk

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Re: Over charging . alternator
« Reply #4 on: June 06, 2017 - 08:25:52 pm »
If you still have an overcharging issue after replacing your dash harness, just post any questions. Here is a prior thread on an overcharging issue with some basic test points A through G listed for reference.

Good luck!
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
1995 Kawasaki ZX1100E & still alive

Offline dodj

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Re: Over charging . alternator
« Reply #5 on: June 07, 2017 - 12:25:00 pm »
Due to the numerous connectors/connections in the wiring harness, poor electrical contact on one or more is usually the cause of overcharging with these cars. Clean the valve cover connections, bulkhead connections, column connections, ammeter connections, relay connections and battery connections. Also battery to engine ground, battery to rad cradle ground, engine to firewall ground and VR case to firewall ground. If all those connections are made to be virtually 0 ohm connections, your overcharging will be a thing of the past.
1973 Challenger  440 4 spd 
2007.5 3500 6.7 Cummins Diesel, Anarchy tuned.
Good friends don't let friends do stupid things. ........alone.