PDA

View Full Version : alternator wont charge battery



lexanbobby
03-13-2012, 09:56 PM
So my alternator is still not charging my battery in my 86 accord lxi. 2 new aLternators. 3 new batteries. had al wires tested n they r getting voltage. battery is good. and both alternators are good. somebody pleaseeee help me i cant afford to take in to a shop. im outta ideas......

ghettogeddy
03-13-2012, 10:03 PM
your sure its not charging and its not just draining from say the clock or something else being on?

lexanbobby
03-13-2012, 10:05 PM
Well ive had it tested while the car is running n its not charging. cables r on nice n tight everything....

A18A
03-13-2012, 10:14 PM
does the light in the dashboard turn off when you start the car? if so, check your main fuses

Hauntd ca3
03-14-2012, 12:08 AM
x2 on the main fuse

Oldblueaccord
03-14-2012, 09:56 AM
Well ive had it tested while the car is running n its not charging. cables r on nice n tight everything....

what is the voltage of the battery at rest( car off) and with it running ?

wp

Dr_Snooz
03-16-2012, 05:26 PM
What condition are your battery cables in? My guess is the cable running to your alternator is not in very good shape.

lexanbobby
03-16-2012, 08:01 PM
Well i checkd the dash lights right now n they dim but go back normal when starting. and voltage was 12 on and off.... weve checkd all the cables they look fine n fuses too

Hauntd ca3
03-17-2012, 02:50 AM
if the voltage with the motor running is 12volts. you more than likely are in need of some brushes for it.
pull the alt off, remove the rear cover and you should see the regulator and brush holder held in by bout 5 screws.
take them out and remove the brush holder. if there are only a couple mm of brush sticking out of the holder, go buy a new brush holder for bout $10 and reverse the process.

lostforawhile
03-17-2012, 05:51 AM
Is there voltage at the field terminal with the key on? Pull the plug out of the alternator turn the key on ignition. One. Of the terminals should show 12 volts between it and ground if not you have a blown fuse, if the alternator warning light doesn't come on with the key,same thing

lexanbobby
03-22-2012, 12:16 AM
Got a third altetnator this time from napa. Still no charge. Plug into alternator has voltage. There voltage at the bolt on alternator. Cables r good. Battery is good. Fuses all look good but some do not light up with the tester.... Everybody thinks I gotta go to an electrician now.... Is it really something ths difficult?

lostforawhile
03-22-2012, 04:33 AM
remind me tonight and I will look through the book, the nappa alternator is usually the good one

Dr_Snooz
03-22-2012, 08:45 PM
What is the voltage at the white wire in the fuse box that comes from the alternator and goes to the battery? If memory serves, the white wire comes directly off the alternator, goes to the screw in the fuse box and from there to the battery. (If that's wrong, someone please correct me). If you're sure the alt and battery are good, then your only possibility is a bad wire, or you hooked something up wrong. Check your ground wires too. Those often get corroded and create lots of electrical joy. If you're certain the wires are okay, just prove me wrong by running a new wire from the alt to the battery.

Pnem3
03-23-2012, 07:14 AM
The car won't even start if the 70 amp large pink fuse under the hood is blown so you can probably rule that out.

lexanbobby
03-25-2012, 07:28 AM
Ok I checked out the wires goin from alternator it goes under the battery to the fuse box and the part that goes under the battery is kinda jacked up... Its showing the white wire and yellow and green wire. On the yellow n green it has a spoy showing acttual wires inside. Soo do I tape it up or do I gotta replace it? I know those r causing problems cuz when I messed with them the car got a couple more points of voltage... Am I on the right teack?

lexanbobby
03-25-2012, 03:45 PM
Messed with the wires n now battery light went on but still no charge...

Dr_Snooz
03-25-2012, 04:17 PM
Replace them.

lostforawhile
03-25-2012, 04:36 PM
what you have going into the alternator plug at least on the carb alternator, is a field wire that is powered with the key on, then you have the wire for the warning light, one side of the warning light bulb is always 12 volts plus with the key on, the status of the warning light wire at the alternator changes depending on if it's charging. if it's charging, that wire is 12 volts plus, since the bulb now has 12 volts on both sides,it stays off,if the alternator stops charging, that wire changes to a negative, this allows the light to come on. the extra wire on the fuel injected alternator, allows the computer to reduce it's output when not needed, this helps fuel economy

Hondamonster
03-25-2012, 06:34 PM
grab a section of fairly thick wire. 10 gauge or so. put one end on the positive terminal on the battery and the other end on the white wire on the alternator. If that fixes it, you have a break in that wire somehow. I had that happen. Not sure how or why, but it works now. :shrug

lexanbobby
03-25-2012, 07:54 PM
will give the new wire a try tomarrow (fingers crossed) will keep posted what happens...

lostforawhile
03-25-2012, 09:32 PM
will give the new wire a try tomarrow (fingers crossed) will keep posted what happens...

if you move those damaged wires and the alternator light comes on, you need to fix those, and you will probably be fine, the alternator needs both the field voltage and on the lxi's the signal from the computer,

lexanbobby
03-27-2012, 01:43 PM
so a honda wire guy came by n said he thinks the plug goin to the back of the alternator is the problem...buty would i have votage there if that was it??? he said a wire to the battery from alternators not gna do anything. he wants us to pay him to rebuild the whole wire harnessi... so is he trippen??? cuz ill probably just end up goin to a junk yard for the harness

ecogabriel
03-27-2012, 02:37 PM
If you get the wiring diagram, you can test each wire in that connector for continuity. The only additional things you would need is a multimeter and a long piece of wire to connect to the wires' other end(s) (the wiring diagram would tell which color goes where).

Dr_Snooz
03-28-2012, 03:19 PM
so a honda wire guy came by n said he thinks the plug goin to the back of the alternator is the problem...buty would i have votage there if that was it??? he said a wire to the battery from alternators not gna do anything. he wants us to pay him to rebuild the whole wire harnessi... so is he trippen??? cuz ill probably just end up goin to a junk yard for the harness

Well, technically, you should rebuild the harness if you want it to look like the factory when you are done, or you can run your own wire for next to free.

lostforawhile
03-28-2012, 08:29 PM
look at the threegeez wiki you can download the electrical trouble shooting manual there

lexanbobby
03-30-2012, 05:19 PM
Ok my brother came by to take another look and heres what happend: he put a bolt he said was missing frm the alternator on we think its to ground it. He checked continuity from alternator to battery and fuse box... Everything was good. And I think it may have been the bolt cuz we checked voltage the whole time n after that we got up to 13.3 volts... BUT the car doesnt charge when being idled... With the car on it now charges but not driving so now what should we check? He even brought another white wire from a diff. Honda n it was doin the same as mine so mines good...

lostforawhile
03-30-2012, 07:33 PM
Ok my brother came by to take another look and heres what happend: he put a bolt he said was missing frm the alternator on we think its to ground it. He checked continuity from alternator to battery and fuse box... Everything was good. And I think it may have been the bolt cuz we checked voltage the whole time n after that we got up to 13.3 volts... BUT the car doesnt charge when being idled... With the car on it now charges but not driving so now what should we check? He even brought another white wire from a diff. Honda n it was doin the same as mine so mines good...

the alternator doesn't ground through a bolt, it grounds through the engine block it's bolted to. check the ground straps from the body to the engine

ecogabriel
03-31-2012, 12:35 AM
x2. check the grounds.... and get rid of the f...ground battery cable and install something better (I used a 4G ground wire there.... longer but way way thicker)

lostforawhile
03-31-2012, 07:13 AM
the heavy white wire goes directly to battery
white/green goes to fuse 8 in the under hood fuse box,and should be hot all the time

black/yellow should be hot with the key on, it goes to fuse 1 and the inside fuse box.

white/blue goes to the charge warning light

on the FI cars white/red goes to the ecu

I can't remember exactly how the ecu reduces charging voltage, but I know the alternator will function with the white/red disconnected, I believe the ecu sends a ground signal to the regulator to reduce charge current when not needed, this improves fuel economy. you could check all the other connections then disconnect the white/red to see if it charges at idle. It could possibly be the ecu thinking the car doesn't need to charge.

Hauntd ca3
03-31-2012, 02:00 PM
is it only giving that 13.3 volts when you give the car a rev, but just back to battery voltage when idling?
to me that sounds like the rectifier has a diode out or the brushes are fucked.

lostforawhile
03-31-2012, 06:12 PM
is it only giving that 13.3 volts when you give the car a rev, but just back to battery voltage when idling?
to me that sounds like the rectifier has a diode out or the brushes are fucked.
well the alternator light stays on even with the alternator unplugged and goes out when you unplug the choke, there should be enough resistance in the choke heater coil to keep the light from coming on by it grounding through the coil. I'm sending him a good choke coil out of my junk, since the alternator changes the status of the blue/white wire to positive when charging, to turn off the charge warning light and power the choke, it seems that that voltage is finding it's way right to ground through the choke coil

lexanbobby
04-01-2012, 10:35 AM
I think I said it wrong it charges at idle but not when getting gas.... When we rev it the charge drops way down.

Dr_Snooz
04-01-2012, 11:28 AM
Ok I checked out the wires goin from alternator it goes under the battery to the fuse box and the part that goes under the battery is kinda jacked up... Its showing the white wire and yellow and green wire. On the yellow n green it has a spoy showing acttual wires inside. Soo do I tape it up or do I gotta replace it? I know those r causing problems cuz when I messed with them the car got a couple more points of voltage... Am I on the right teack?

Have you fixed this problem yet or are you still trying to charge with exposed wires that are likely grounding out on things?

lexanbobby
08-14-2012, 07:15 AM
Sorry people mived a couple times and had no phone to log on with... Welll still having the issues. Car no longer charges while on at all. Battery starting to take forever to charge- got a hone charger to help till we get the funds to fix it... Dash lights not lighting up, tail lights have gone out, more than half of the fuses in under dash fuse box dont light up- but have been checked and r good, did replace a few to c if it helps, oh and speedometer acting up...works when it wants to basically, and drivers front power window wont roll up anymore, and off the subject- motor mount keeps losing a bolt...so theres a fun update for eveyone lol

POS carb
08-14-2012, 02:53 PM
PM me

Dr_Snooz
08-14-2012, 06:41 PM
The gods are angry with you. :(

deathblood6
12-05-2014, 12:02 PM
Am experiencing the same exact problem- so far I ruled out the alternator being bad and the battery- (they are brand new) I did a continuity test by disconnecting the battery negative cable and connecting an old school volt meter - lit up like a Christmas tree! I started pulling fuses one by one (engine bay main fuse box) - I was getting constant power through the negative battery cable to my battery - when I pulled the clock fuse the voltmeter light immediately turned off! That didn't fix the problem when I pulled it but its a starting point to diagnosing the issue. Hopefully I can solve this issue but it's most differently a ground issue and some sort of breakage somewhere in the charging system :( if anyone can help! Chime in please!


New Battery not charging / alternator not reading 14v - ground issue ? Wiring issue? All the symtoms of a bad alternator but simply not the case -:(

deathblood6
12-07-2014, 04:18 PM
Ok- I found out my issue - bad new factory parts! replaced the alternator for a third time and BAME! Power to the alternator ! - I did some serious testing to be sure that my wiring harnesses from the voltage regulator wasn't the culprite / I have some suggestions for the individual still struggling with the no charge alternator issue - test all ports at the voltage regulator harness plug for power on all four wires /be sure your car is in start mode (key in ignition turned /not started) you should have power from all four connections/ voltage reading should be in the 12.0 range for three of the four connections and one should read about 4.57 or 5.0 (that's the wire to the ecu) if you aren't getting power through anyone of those connections--you can bet it's a broken wire or bad connection - otherwise -test your new parts to be sure they aren't faulty :) hope this helps

Shane86
05-19-2016, 02:36 PM
Replace your starter what happened to mind my starter worked fine had it tested tested fine was losing power to my starter

mikeharriswho
10-02-2016, 02:59 PM
Ok- I found out my issue - bad new factory parts! replaced the alternator for a third time and BAME! Power to the alternator ! - I did some serious testing to be sure that my wiring harnesses from the voltage regulator wasn't the culprite / I have some suggestions for the individual still struggling with the no charge alternator issue - test all ports at the voltage regulator harness plug for power on all four wires /be sure your car is in start mode (key in ignition turned /not started) you should have power from all four connections/ voltage reading should be in the 12.0 range for three of the four connections and one should read about 4.57 or 5.0 (that's the wire to the ecu) if you aren't getting power through anyone of those connections--you can bet it's a broken wire or bad connection - otherwise -test your new parts to be sure they aren't faulty :) hope this helps

So I tested the connections like you said and found that one wire is not getting voltage. It's the white/green wire which is the one going to fuse no. 8, as I understand it, which is for the voltage regulator. Any suggestions on how to replace that wire?

Oldblueaccord
10-02-2016, 11:09 PM
So I tested the connections like you said and found that one wire is not getting voltage. It's the white/green wire which is the one going to fuse no. 8, as I understand it, which is for the voltage regulator. Any suggestions on how to replace that wire?

But the fuse is good correct?

mikeharriswho
10-04-2016, 07:16 AM
The fuse was good. So here's an update. I replaced the wire going from the voltage regulator to fuse no 8. I'm getting a charge but I'm only getting 11v

Oldblueaccord
10-04-2016, 01:32 PM
If you look in to book there is a way to make the alt go full field for a test. I am not sure how to do it. And make sure your alt is for a fuel injected car.

Good chance the alt is just bad.

mikeharriswho
10-18-2016, 06:24 AM
Thanks for the info. The alternator was definitely for the fuel injected car. Here's the update: Ive gone through 5 alternators, all of them remanufactured. I have tested all the contacts in the 4 pin connector and all of them are receiving voltage from the battery. I took the car to an automotive electrician. He said everything is fine but the alternator. I was told that I need to buy a Denso alternator for the car but cant seem to find a new one. They are all remanufactured. I will have to take a chance at it and buy a reman Denso alternator I guess. Any input guys?

Dr_Snooz
10-18-2016, 07:19 PM
I'd take a flier on a reman Denso. I wouldn't on a non-OEM rebuilder though.

mikeharriswho
10-20-2016, 07:29 AM
I'd take a flier on a reman Denso. I wouldn't on a non-OEM rebuilder though.

I ordered it. Hope it works. I'll keep you updated!

mikeharriswho
10-27-2016, 03:24 PM
So I got the denso today, installed it. Still same issue. Only charging at 12v. Can't figure out what the problem is...

Dr_Snooz
10-27-2016, 06:59 PM
What is the resistance in the white wire that goes from the alternator to the underhood fuse block? Check that all very carefully. Look for damage to the wire, corrosion on the connectors, melted plastic, etc. Better yet, take all the connections apart, wire brush, then coat with silicone grease and re-assemble.

Are you having any other electrical issues?

Edit: also check your engine grounds.

More edit: how old/sulfated is your battery?

Oldblueaccord
10-28-2016, 08:15 PM
So I got the denso today, installed it. Still same issue. Only charging at 12v. Can't figure out what the problem is...

have your electrical buddy check that alt again or better yet have him rebuild it so you know it works.

Revving it to 2000 rpms you get the same 12v? They wont charge much at idle sometimes.

mikeharriswho
10-30-2016, 12:02 PM
I don't see the white wire going to the fuse block. I'm not having any electrical issues. The battery is new and the engine grounds are good.

mikeharriswho
10-30-2016, 12:09 PM
Tried holding at 2000 rpm, no fluctuation in charge

mikeharriswho
10-30-2016, 12:10 PM
Also guys, the battery light is not on!

mikeharriswho
10-30-2016, 04:24 PM
Okay changed bulb. Battery light back on and is staying on

Oldblueaccord
10-30-2016, 09:34 PM
Okay changed bulb. Battery light back on and is staying on

Where are you testing the 12v at?

Im thinking check it right at the alt itself. main lug.

Please tell me you are NOT lifting the positive terminal on and off with the car running to check for charging,that will kill and alt quick.

mikeharriswho
10-31-2016, 05:34 AM
No I'm not doing that lol. I'm checking the voltage at the post on the alternator. It seems to match the battery voltage everytime.