Battery not charging

Mustang_289 · 01-03-2002, 07:14 PM

Well - my son and I have made some great progress on putting our project 88GT stang back together. I got him a set of underdrive MAC pullies for x-mas and other goodies. We were having battery charging problems before prior to installing a new battery, upgraded alternator to 130amp PA-Performance.

At best I'm seeing 12.4 volts across the battery at idle - turn on a couple of accessories and drops a little below 12 volts. Not good enough to charge the battery. Is there any know issues with inline fuse links with 88GTs that could cause battery not to charge right? Any ideas on areas to troubleshoot. Man these electrical problems sometimes are tough ones! Thanx in advance for any possible help.

Fox Body · 01-03-2002, 08:33 PM

Excuse me for asking, but how do you know for sure if that is not enough to charge the battery?

Mustang_289 · 01-03-2002, 09:04 PM

Normally you should be seeing around 14.4 volts across the battery while engine is running. If you're seeing right at 12-volts it's usually battery voltage and not alternator voltage.

joegodfrey · 01-03-2002, 09:32 PM

Sounds to me like you said you had problem with an existing battery? If so:
Don't know about that particular vehicle, but same thing happened to me couple years ago. I checked everything, called a few shops, they told me to get a new battery among other things. I had a friend look at it, and he gave it back an hour later and laughed at me. It turns out the battery terminals were a little corroded or something, not even enough to see, so he cleaned them up and it was fine. This was after I spent to weeks trying to figure if I had a short or a bad alternator. I still feel stupid when I think about it.

Obviously if you have a new battery with that problem, just ignore the above, but it could be a minor connection problem.

Hope that helps.

stanger8172 · 01-03-2002, 09:45 PM

Test the battery by itself. If it reads 12.6 or lower than it needs a charge. If you always have to charge it than something is drawing from it ( racing pulley doesn't help). The battery is problably shot too.

Does the starter growl on a start-up? If so it is shot too and it might be drawing too much from the battery.

You may have a fuse that is blown and is drawing from the battery too.

Good luck

Coolbreeze · 01-04-2002, 12:24 AM

Like stated check for corred post but it sound like the ALT isn't putting out enough. Has the ALT been checked yet??????? If not try that..

2FastLX · 01-04-2002, 01:18 AM

I have the MAC under drive pulleys and the 3G. I have absolutely no charging problems whatsoever. Even with all the accessories on when I rev the engine you can't see the head lights brighten up at all. This setup is a beast of a system. You must either have a bad battery, or a bad connection. Get a volt meter and start from the alternator and work your way back.

One question... when you installed the 3G did you upgrade the alternator wire that runs back to the solenoid? If not I'd recommend stepping up to 2 or 4 gauge welding cable. Check the ground from the battery to the engine block too.

You might try throwing another battery in the car for a day or so if you have one and see how that does. I took a battery to Auto Zone and they told me it was good so I searched for the problem elsewhere replacing everything along the way. I finally found myself right back where I started and bought a new battery which solved my problem =P

Good luck.

PKRWUD · 01-04-2002, 05:17 AM

It's not the battery. It's either the alternator itself (unlikely), or too much resistance in the circuit back to the battery (more likely). The battery really is just there for starting the engine. After that, it's no longer used (while running) unless the alternator's output falls below 12.6vdc. Once the engine is started, the alternator replaces the the energy the battery spent starting the engine, which usually takes less than 30 seconds. After that, the electrical system runs off the alternator, not the battery, so a weak battery shouldn't affect the voltage reading across the posts while running. Connect a DMM at idle again, and observe it while accelerating to 2000 rpms. What happens to the DMM?

Take care,
-Chris

Mustang_289 · 01-04-2002, 07:07 AM

When I upgraded to the 3G alternator I did install the 4gauge charge wire for the increased amps. We have pretty much a brand new charging system with alt, battery and battery cables, even a new starter selenoid.

I'll test the suggestions you guys have and post the results - thanx again for the help!

01-03-2002, 07:14 PM	#1
Mustang_289 Registered Member Join Date: Sep 2001 Posts: 512	Battery not charging Well - my son and I have made some great progress on putting our project 88GT stang back together. I got him a set of underdrive MAC pullies for x-mas and other goodies. We were having battery charging problems before prior to installing a new battery, upgraded alternator to 130amp PA-Performance. At best I'm seeing 12.4 volts across the battery at idle - turn on a couple of accessories and drops a little below 12 volts. Not good enough to charge the battery. Is there any know issues with inline fuse links with 88GTs that could cause battery not to charge right? Any ideas on areas to troubleshoot. Man these electrical problems sometimes are tough ones! Thanx in advance for any possible help.

01-03-2002, 08:33 PM	#2
Fox Body Mustang Maniac Join Date: Sep 2000 Location: GA, U.S.A Posts: 2,266	Excuse me for asking, but how do you know for sure if that is not enough to charge the battery? __________________ 351W-powered 1979 Ford Mustang Ghia notchback '79 Video @ Idle Stock 5.8L under 4" cowl 'glass hood, C4 w/ Transgo shift kit, Holley 750 cfm, Edelbrock Performer RPM intake; Fluidyne Al radiator, Flexalite 175 electric fan, 1 5/8" MAC shorty headers, FRPP Al driveshaft; S&W 6-point cage; 2.5" Off road H-pipe, 2-chamber Flowmasters, 8.8" Rear w/ 3.55s; Weld wheels (15x6;15x8), Front: 225/60/15, Rear: 275/50/15 Nitto NT 555R Drag Radials; 14 x 4” K&N X-stream air filter. '92 GT (5-speed) Small In Car Video Stock 5.0L, 2-chamber Flowmasters, MAC CAI, Tri-Ax, Al pedals... "Red, thou art my companion. Hasten now your quickened metamorphosis to Green that I may conquer all who dare abide there beside me. May they be left thither behind burnt black." ---Fox Body

01-03-2002, 09:45 PM	#5
stanger8172 Registered Member Join Date: Nov 2000 Location: Milwaukee,Wisconsin Posts: 380	Test the battery by itself. If it reads 12.6 or lower than it needs a charge. If you always have to charge it than something is drawing from it ( racing pulley doesn't help). The battery is problably shot too. Does the starter growl on a start-up? If so it is shot too and it might be drawing too much from the battery. You may have a fuse that is blown and is drawing from the battery too. Good luck __________________ '91 LX convertible , T-5, Centerforce Dual Friction, MSD Blaster Coil, FR 9MM wires, 13* timing, 1.6rr, ported/polished/milled stock heads, 1.94/1.60 stainless valves, March Performance Pulleys, K&N panel, 1"spacer, BBK shorties, 2 1/2" off road H, Summit 2 1/2" catback

01-04-2002, 12:24 AM	#6
Coolbreeze Registered Member Join Date: Oct 2000 Location: ~Columbus~GA~31909~ Posts: 156	Like stated check for corred post but it sound like the ALT isn't putting out enough. Has the ALT been checked yet??????? If not try that.. __________________ Mike Blown~AOD'ed~331~ T-top~ 86GT Check out car on my page here ------ > ~~My 86GT T-top ~~

01-04-2002, 01:18 AM	#7
2FastLX The Photoshop Guru Join Date: Feb 2001 Location: Mecca, Indiana Posts: 1,419	I have the MAC under drive pulleys and the 3G. I have absolutely no charging problems whatsoever. Even with all the accessories on when I rev the engine you can't see the head lights brighten up at all. This setup is a beast of a system. You must either have a bad battery, or a bad connection. Get a volt meter and start from the alternator and work your way back. One question... when you installed the 3G did you upgrade the alternator wire that runs back to the solenoid? If not I'd recommend stepping up to 2 or 4 gauge welding cable. Check the ground from the battery to the engine block too. You might try throwing another battery in the car for a day or so if you have one and see how that does. I took a battery to Auto Zone and they told me it was good so I searched for the problem elsewhere replacing everything along the way. I finally found myself right back where I started and bought a new battery which solved my problem =P Good luck. __________________ Project: 1988 Coupe - EFI 5.8L Twin Turbo with Victor intake, Canfield heads, F303 cam, March aluminum underdrive pulleys, TKO (or T56 if funds permit), PBR twin piston calipers and 13" rotors up front, 94 Cobra rear calipers and 12" rotors on the rear, 3.73's, Griggs K-member, tubular front control arms, torque arm and panhard bar, polished 99 Cobra wheels. "The GR-40 kit installation is now complete, and the humble Fox-chassis car will now out-corner and out-stop a ZR-1 or a Viper, and support massive horsepower additions with perfect balance." Griggs Racing ICQ# 42269241

01-03-2002, 09:04 PM	#3
Mustang_289 Registered Member Join Date: Sep 2001 Posts: 512	Normally you should be seeing around 14.4 volts across the battery while engine is running. If you're seeing right at 12-volts it's usually battery voltage and not alternator voltage.

01-03-2002, 09:32 PM	#4
joegodfrey Registered Member Join Date: Dec 2001 Location: Syracuse, NY Posts: 39	Sounds to me like you said you had problem with an existing battery? If so: Don't know about that particular vehicle, but same thing happened to me couple years ago. I checked everything, called a few shops, they told me to get a new battery among other things. I had a friend look at it, and he gave it back an hour later and laughed at me. It turns out the battery terminals were a little corroded or something, not even enough to see, so he cleaned them up and it was fine. This was after I spent to weeks trying to figure if I had a short or a bad alternator. I still feel stupid when I think about it. Obviously if you have a new battery with that problem, just ignore the above, but it could be a minor connection problem. Hope that helps.

01-04-2002, 05:17 AM	#8
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	It's not the battery. It's either the alternator itself (unlikely), or too much resistance in the circuit back to the battery (more likely). The battery really is just there for starting the engine. After that, it's no longer used (while running) unless the alternator's output falls below 12.6vdc. Once the engine is started, the alternator replaces the the energy the battery spent starting the engine, which usually takes less than 30 seconds. After that, the electrical system runs off the alternator, not the battery, so a weak battery shouldn't affect the voltage reading across the posts while running. Connect a DMM at idle again, and observe it while accelerating to 2000 rpms. What happens to the DMM? Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

01-04-2002, 07:07 AM	#9
Mustang_289 Registered Member Join Date: Sep 2001 Posts: 512	When I upgraded to the 3G alternator I did install the 4gauge charge wire for the increased amps. We have pretty much a brand new charging system with alt, battery and battery cables, even a new starter selenoid. I'll test the suggestions you guys have and post the results - thanx again for the help!

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