Battery Wont Charge While Car Is Running Need Help Please!!!

88sbcmustang · January 31st, 2010, 03:52 AM

so i have an 88 2.3 mustang and when the car is running the alternator wont charge the battery and iv had the alternator checked it was good iv replaced the plug on the alternator cause i heard they go out and the battery is a good battery i cant find a wiring diagram anywhere i need help PLEASE!!! i just wanna drive my fox

Imran · January 31st, 2010, 05:00 AM

try out a new alternator anyways. If still it does not work, return it.

87StangGT · January 31st, 2010, 08:45 AM

Check voltage when the car isnt running should be around 12v then check it when it is running with nothing on (radio lights a/c) it should raise to about 13-14v. If it doesnt then its a bad alternator. its possible the guy at the auto parts place didnt know what he was doing and the alternator is in fact bad. has happened to me before.

Like Jakashh said go buy one you can always return it.

88sbcmustang · January 31st, 2010, 10:28 PM

it starts at 8 with nothing on and it just drops when Im driving untill the car just dies

Imran · January 31st, 2010, 10:53 PM

seems like your alternator isn't charging.

88sbcmustang · January 31st, 2010, 11:23 PM

i take it off and have my local parts store test it and it charges just fine though is there a fusible link somewhere i missed?

perry2k12 · January 31st, 2010, 11:51 PM

my buddy had the same problem and went and got his alternator tested at the parts store. they said it was ok. guess what the problem turned out to be in the end? alternator

fastback lover · February 1st, 2010, 08:00 AM

I would have to agree with the alt. When I used to work at checkers we were told to make the alt. and starter pass if it would mean a warrenty return. If you want to belive the parts guys then follow the wires and make sure they are in good shape. But take the alt. to napa. They are normally good about the test.

cusp · February 1st, 2010, 02:28 PM

Is the voltage regulator built in to the alt? If not then check that too. The VR works by regulating the field current. If there is no FC, there will be no alt output.

87StangGT · February 1st, 2010, 05:45 PM

Yep its the alternator.

88sbcmustang · February 7th, 2010, 04:59 AM

Replaced the alternator with a brand new one still aint workin is there a wiring diagram for the charging system i could get somewhere or is there just something im missing all i know is that this really sucks

87StangGT · February 7th, 2010, 09:26 AM

EDIT: Other link did not work this one should.

http://www.veryuseful.com/mustang/te...nks-ign-ac.gif

Try this...

Did you get the right alternator for your car?

Also check all you wires make sure you have nothing backwards, check the voltage at the back of the alternator. Possibly have something backwards or have a bad diode in the alternator which could also cause short in the battery somewhere. if it has a bad diode you could take it to the parts place and it will test good all day test good but don't work if one or more of the diodes inside are bad.
but try the wire diagram see if that works for you.

necro5.0 · February 7th, 2010, 04:35 PM

Originally Posted by 88sbcmustang

it starts at 8 with nothing on and it just drops when Im driving untill the car just dies

It sounds to me like your battery is bad, it should read at least 12.8 volts with the car not running, and it shouldn't drop past 12 while you're cranking the engine. If it's dropping to 8 volts then it's either bad, or about to be... also check your voltage regulator if you have one that's external of the alternator...

Iwannagofast · February 7th, 2010, 10:52 PM

bad ground maybe?

calgarynotch · February 8th, 2010, 12:07 AM

personaly if any fox mustang owner has any charging or alternator problems....do yourself a favor and do the 3g swap with a good napa premium unit and 4g wire to the solenoid. as far as i know the alternator trigger wire runs into the volt gauge. mine came loose behind the cluster and wouldn't charge either after i did my swap

88sbcmustang · February 25th, 2010, 09:37 PM

i tried and tried and finally said f*ck it and bought a 3g alternator and wiring harness fixed everything

January 31st, 2010, 03:52 AM	#1
88sbcmustang Newbie 1988 mustang hatchback Join Date: Jan 2010 Location: springfield Posts: 28 iTrader: 0 reviews	Battery Wont Charge While Car Is Running Need Help Please!!! so i have an 88 2.3 mustang and when the car is running the alternator wont charge the battery and iv had the alternator checked it was good iv replaced the plug on the alternator cause i heard they go out and the battery is a good battery i cant find a wiring diagram anywhere i need help PLEASE!!! i just wanna drive my fox

January 31st, 2010, 05:00 AM	#2
Imran :) 01 Join Date: Dec 2007 Posts: 10,795 iTrader: 1 reviews	try out a new alternator anyways. If still it does not work, return it. __________________

January 31st, 2010, 10:53 PM	#5
Imran :) 01 Join Date: Dec 2007 Posts: 10,795 iTrader: 1 reviews	seems like your alternator isn't charging. __________________

February 1st, 2010, 02:28 PM	#9
cusp Regular 2008 Mustang GT Join Date: Jun 2009 Location: Santa Barbara, California Posts: 114 iTrader: 0 reviews	Is the voltage regulator built in to the alt? If not then check that too. The VR works by regulating the field current. If there is no FC, there will be no alt output. __________________ 2008 manual GT with deluxe trim, FRPP CAI, FRPP GTB Mufflers & 91 All Out Tillman Tune. 3.73 gears, Coast Ultralight Drive-shaft. 18" OEM Polished Bullitts, Webelectric Sequentials, XM built into the Shaker 500. Alarm and Escort RedLine.

February 7th, 2010, 09:26 AM	#12
87StangGT Regular 1987 Mustang GT Join Date: Oct 2009 Location: Cape Coral, FL Posts: 131 iTrader: 0 reviews	EDIT: Other link did not work this one should. http://www.veryuseful.com/mustang/te...nks-ign-ac.gif Try this... Did you get the right alternator for your car? Also check all you wires make sure you have nothing backwards, check the voltage at the back of the alternator. Possibly have something backwards or have a bad diode in the alternator which could also cause short in the battery somewhere. if it has a bad diode you could take it to the parts place and it will test good all day test good but don't work if one or more of the diodes inside are bad. but try the wire diagram see if that works for you. Last edited by 87StangGT; February 7th, 2010 at 04:36 PM.

January 31st, 2010, 08:45 AM	#3
87StangGT Regular 1987 Mustang GT Join Date: Oct 2009 Location: Cape Coral, FL Posts: 131 iTrader: 0 reviews	Check voltage when the car isnt running should be around 12v then check it when it is running with nothing on (radio lights a/c) it should raise to about 13-14v. If it doesnt then its a bad alternator. its possible the guy at the auto parts place didnt know what he was doing and the alternator is in fact bad. has happened to me before. Like Jakashh said go buy one you can always return it.

January 31st, 2010, 10:28 PM	#4
88sbcmustang Newbie 1988 mustang hatchback Join Date: Jan 2010 Location: springfield Posts: 28 iTrader: 0 reviews	it starts at 8 with nothing on and it just drops when Im driving untill the car just dies

January 31st, 2010, 11:23 PM	#6
88sbcmustang Newbie 1988 mustang hatchback Join Date: Jan 2010 Location: springfield Posts: 28 iTrader: 0 reviews	i take it off and have my local parts store test it and it charges just fine though is there a fusible link somewhere i missed?

January 31st, 2010, 11:51 PM	#7
perry2k12 Newbie Join Date: Nov 2009 Posts: 27 iTrader: 0 reviews	my buddy had the same problem and went and got his alternator tested at the parts store. they said it was ok. guess what the problem turned out to be in the end? alternator

February 1st, 2010, 08:00 AM	#8
fastback lover Zip Your my Hero.... 1988 Mustang LX N/A Join Date: Sep 2007 Location: Arizona Posts: 918 iTrader: 0 reviews	I would have to agree with the alt. When I used to work at checkers we were told to make the alt. and starter pass if it would mean a warrenty return. If you want to belive the parts guys then follow the wires and make sure they are in good shape. But take the alt. to napa. They are normally good about the test.

February 1st, 2010, 05:45 PM	#10
87StangGT Regular 1987 Mustang GT Join Date: Oct 2009 Location: Cape Coral, FL Posts: 131 iTrader: 0 reviews	Yep its the alternator.

February 7th, 2010, 04:59 AM	#11
88sbcmustang Newbie 1988 mustang hatchback Join Date: Jan 2010 Location: springfield Posts: 28 iTrader: 0 reviews	Replaced the alternator with a brand new one still aint workin is there a wiring diagram for the charging system i could get somewhere or is there just something im missing all i know is that this really sucks

February 8th, 2010, 12:07 AM	#15
calgarynotch Regular 1989 LX coupe Join Date: Jul 2009 Location: calgary Posts: 79 iTrader: 0 reviews	personaly if any fox mustang owner has any charging or alternator problems....do yourself a favor and do the 3g swap with a good napa premium unit and 4g wire to the solenoid. as far as i know the alternator trigger wire runs into the volt gauge. mine came loose behind the cluster and wouldn't charge either after i did my swap

February 25th, 2010, 09:37 PM	#16
88sbcmustang Newbie 1988 mustang hatchback Join Date: Jan 2010 Location: springfield Posts: 28 iTrader: 0 reviews	i tried and tried and finally said f*ck it and bought a 3g alternator and wiring harness fixed everything

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