Charging problems. Need help
04-18-10, 08:46 PM
#1
Full Member
Thread Starter
iTrader: (4)
Join Date: Mar 2010
Location: Tallahassee
Posts: 237
Likes: 0
Received 0 Likes
on
0 Posts
Charging problems. Need help
Im having problems keeping the battery voltage higher then right around 12 volts. When the car is idleing it has 11.96 volts. When i rev it up to about 4500 RPMs it gets to around 12.6 volts. When the ignition is off the battery holds 12.16 volts. The battery is brand new and the alternator has been tested and it checked ok. Some of the time when I get on the brakes and the car is idleing the voltage drops really low and it tends to cut off but if I get on the clutch or put it in neutral and rev it out the voltage goes back to around 12 on the gauge inside the car. I have the receipt from the previous owner for the alternator and it is from 4/8/05. Im not sure if the alternator is actually bad and the tester isnt testing it correct or Im having a short or drain. My brother is a certified mechanic and I had told him what was going on over the phone since he lives a few hours away and he said it sounds like the voltage regulator. It just started last week on thursday. Any help would be greatly appreciated.
Thanks in advance.
Thanks in advance.
04-18-10, 09:37 PM
#2
HAILERS
Join Date: May 2001
Location: FORT WORTH, TEXAS,USA
Posts: 20,563
Likes: 0
Received 21 Likes
on
19 Posts
You go to your series four alt and look to see if the small plug is on the back of the alternator. Two wires in that plug. White/Black and Black/White.
The BLACK/WHITE wire is switched voltage from the ignition for the regulator. The WHITE/BLACK wire has two functions, one of which is to make the Warning Light cluster lights ALL come on if the alternator isn't putting out. Such as key ON, engine OFF condition.
Black/White gets fed from the ENGINE fuse. If the engine starts, then that fuse is good.
White/Black gets fed ....more or less from the METER fuse. If the gauges work, that fuse is good.
If the car is a series five.......ya shoulda said that, 'cause it's different than the above.
The BLACK/WHITE wire is switched voltage from the ignition for the regulator. The WHITE/BLACK wire has two functions, one of which is to make the Warning Light cluster lights ALL come on if the alternator isn't putting out. Such as key ON, engine OFF condition.
Black/White gets fed from the ENGINE fuse. If the engine starts, then that fuse is good.
White/Black gets fed ....more or less from the METER fuse. If the gauges work, that fuse is good.
If the car is a series five.......ya shoulda said that, 'cause it's different than the above.
04-19-10, 06:22 AM
#4
mmm doritos
iTrader: (4)
Join Date: Apr 2006
Location: lancaster PA
Posts: 2,107
Likes: 0
Received 0 Likes
on
0 Posts
if your alternator ends up being junk i have a really nice used one that only has about 200 miles on it, it also comes with a $25 double groove pulley with the rotor design on it..ill sell cheap!
04-19-10, 07:12 AM
#5
HAILERS
Join Date: May 2001
Location: FORT WORTH, TEXAS,USA
Posts: 20,563
Likes: 0
Received 21 Likes
on
19 Posts
How about taking a look to see if the plug is on the alternator???????????????????????????????????????? ?????????????
When you turn the key to just ON, do all the warning lights in the warning light cluster come on?
Have you taken you digital meter out to the alternator when the cars running, and seen what the voltage is on the battery? Or at the large terminal of the alternator. If not, do it. Digital meters cost ten bucks at Harbour Freight.
When you turn the key to just ON, do all the warning lights in the warning light cluster come on?
Have you taken you digital meter out to the alternator when the cars running, and seen what the voltage is on the battery? Or at the large terminal of the alternator. If not, do it. Digital meters cost ten bucks at Harbour Freight.
04-19-10, 02:09 PM
#6
Full Member
Thread Starter
iTrader: (4)
Join Date: Mar 2010
Location: Tallahassee
Posts: 237
Likes: 0
Received 0 Likes
on
0 Posts
Yes the plug is in the back of the alt. When I turn the key to the on position, all the warning lights come on. I checked the power going to the battery from the back of the alt and it was the same that is on the battery. 11.96 when its idling. When I rev the car out it barely gets to 12.6 volts. how much power should be coming from the plug though? I also had let the car run without the plug and it didnt change the voltage reading..
04-19-10, 03:01 PM
#7
HAILERS
Join Date: May 2001
Location: FORT WORTH, TEXAS,USA
Posts: 20,563
Likes: 0
Received 21 Likes
on
19 Posts
Well, at say 1000rpm, the readings should be close to 14vdc. The 12vdc ain't a cutting it at all. No good.
If you pull the small plug off the alt and turn the key to ON engine OFF, both wires in the plug should read close to batt voltage.
Look especially at the BLACK/WHITE wire for batt voltage. We KNOW the WHITE/BLACK wire is good because the warning lights come on in full.
And or try this: Start the car up. Quickly rev it to say 5 grand and let off the pedal. Now see if the alternator is putting out closer to 14vdc. This will work on a regulator that isn't getting pwr from the BLACK/WHITE wire. The alt will self excite itself by the high revs and then keep on putting out power til the key is put off. Then you'd have to do this each and everytime you start the car, but it's not good because the alt isn't putting out regulated voltage.
The shop that tested it...........hmmmm.
If you pull the small plug off the alt and turn the key to ON engine OFF, both wires in the plug should read close to batt voltage.
Look especially at the BLACK/WHITE wire for batt voltage. We KNOW the WHITE/BLACK wire is good because the warning lights come on in full.
And or try this: Start the car up. Quickly rev it to say 5 grand and let off the pedal. Now see if the alternator is putting out closer to 14vdc. This will work on a regulator that isn't getting pwr from the BLACK/WHITE wire. The alt will self excite itself by the high revs and then keep on putting out power til the key is put off. Then you'd have to do this each and everytime you start the car, but it's not good because the alt isn't putting out regulated voltage.
The shop that tested it...........hmmmm.
Trending Topics
04-19-10, 05:14 PM
#8
Full Member
Thread Starter
iTrader: (4)
Join Date: Mar 2010
Location: Tallahassee
Posts: 237
Likes: 0
Received 0 Likes
on
0 Posts
Ok, I just tried that. The wire is getting nothing with key off, with the key on its getting 11.75. The battery has 12.54 once i cut the car off. not sure how that works but its gets charged back up some. Is there anyway to just make a straight wire from there to the battery or something to see if it will charge right if there is a short in the wire?
04-19-10, 05:41 PM
#10
Full Member
iTrader: (2)
Join Date: Nov 2008
Location: Maryland
Posts: 84
Likes: 0
Received 0 Likes
on
0 Posts
Well, at say 1000rpm, the readings should be close to 14vdc. The 12vdc ain't a cutting it at all. No good.
If you pull the small plug off the alt and turn the key to ON engine OFF, both wires in the plug should read close to batt voltage.
Look especially at the BLACK/WHITE wire for batt voltage. We KNOW the WHITE/BLACK wire is good because the warning lights come on in full.
And or try this: Start the car up. Quickly rev it to say 5 grand and let off the pedal. Now see if the alternator is putting out closer to 14vdc. This will work on a regulator that isn't getting pwr from the BLACK/WHITE wire. The alt will self excite itself by the high revs and then keep on putting out power til the key is put off. Then you'd have to do this each and everytime you start the car, but it's not good because the alt isn't putting out regulated voltage.
The shop that tested it...........hmmmm.
If you pull the small plug off the alt and turn the key to ON engine OFF, both wires in the plug should read close to batt voltage.
Look especially at the BLACK/WHITE wire for batt voltage. We KNOW the WHITE/BLACK wire is good because the warning lights come on in full.
And or try this: Start the car up. Quickly rev it to say 5 grand and let off the pedal. Now see if the alternator is putting out closer to 14vdc. This will work on a regulator that isn't getting pwr from the BLACK/WHITE wire. The alt will self excite itself by the high revs and then keep on putting out power til the key is put off. Then you'd have to do this each and everytime you start the car, but it's not good because the alt isn't putting out regulated voltage.
The shop that tested it...........hmmmm.
04-19-10, 05:50 PM
#11
Full Member
Thread Starter
iTrader: (4)
Join Date: Mar 2010
Location: Tallahassee
Posts: 237
Likes: 0
Received 0 Likes
on
0 Posts
When I start mine the volts drop to around 9-10 volts but once its running it jumps back up to slightly under 12 volts. I really would like to know what it is. I haev a feeling its the alternator. I have a buddy that just wrecked his s5 and is going to let me get the alt off it to try since his was fine. Im hoping thats all it is and me not have to chase wires down.
04-19-10, 06:24 PM
#12
During cranking the alternator isn't doing anything. At that point you're running straight off the battery, so on anything less than a fully charged battery a dip in voltage is likely. The starter pulls a LOT of current.
To the OP, keep in mind that if you want to use an S5 alternator in an S4 car, you'll have to do a little rewiring. See the FAQ: https://www.rx7club.com/showthread.p...72#post5131072. The B/W wire which normally gets switched 12V power, needs to be rerouted to a fused constant 12v source. The empty slot in the main fuse box is a good place for this.
To the OP, keep in mind that if you want to use an S5 alternator in an S4 car, you'll have to do a little rewiring. See the FAQ: https://www.rx7club.com/showthread.p...72#post5131072. The B/W wire which normally gets switched 12V power, needs to be rerouted to a fused constant 12v source. The empty slot in the main fuse box is a good place for this.
04-19-10, 06:26 PM
#13
HAILERS
Join Date: May 2001
Location: FORT WORTH, TEXAS,USA
Posts: 20,563
Likes: 0
Received 21 Likes
on
19 Posts
The regulator on a series five has power on it all the time from the EGI fuse in the engine bay and that fuse feeds one of the two wires on the small connector on the alternator.
Your alternator is SELF EXCITING but is not putting out regulated voltage.
That small wire should be the one that is W/L or white with blue stripe on it. Pull the plug off and see if it has batt voltage on it. No key required. No engine running required. Just pull off and it should have batt voltage. If it does, I'd guess the alt regulator is kaput. The regulators cost $25 bucks online and can be installed by a skilled professional .....or amateur like me if one has a soldering iron and imagination.
04-19-10, 07:19 PM
#14
Full Member
Thread Starter
iTrader: (4)
Join Date: Mar 2010
Location: Tallahassee
Posts: 237
Likes: 0
Received 0 Likes
on
0 Posts
Alright. Can someone give me a visual or more detailed information on rewiring a s5 alternator? and a s5 alt has constant power so does that mean it would be better?
04-19-10, 08:23 PM
#15
The S5 alternator is better since it's 80A (versus the 70A S4), but I don't think the way the regulator is powered is significant.
For an alternator conversion, click the FAQ link I gave you. There's a diagram of how the wires need to be routed.
Get the plug for the S5 alt. and leave a short bit of wire to splice your harness to. Cut the white 2-wire plug (w/ B/W & W/B wires) off of your S4 harness. Connect the W/B wire to the L terminal (see diagram), and cap off the B/W wire. Take a new piece of wire and connect it to the S terminal (again see diagram) on the S5 alt. Take the other end of this wire and solder a non-insulated female spade terminal onto the end. Plug this spade terminal into the bottom of the black plug that plugs into the bottom of the main fuse block (at the open slot). There will be a little tab that holds the wire in place. Take a 30A automotive fuse (about $3 at an auto parts store) and install it in the slot.
Next, take the B-post off of the S4 alt. and swap it with the S5 alt's post. The ring terminals are different size, so matching the smaller post to your smaller S4 terminal is easiest. And that's it.
For an alternator conversion, click the FAQ link I gave you. There's a diagram of how the wires need to be routed.
Get the plug for the S5 alt. and leave a short bit of wire to splice your harness to. Cut the white 2-wire plug (w/ B/W & W/B wires) off of your S4 harness. Connect the W/B wire to the L terminal (see diagram), and cap off the B/W wire. Take a new piece of wire and connect it to the S terminal (again see diagram) on the S5 alt. Take the other end of this wire and solder a non-insulated female spade terminal onto the end. Plug this spade terminal into the bottom of the black plug that plugs into the bottom of the main fuse block (at the open slot). There will be a little tab that holds the wire in place. Take a 30A automotive fuse (about $3 at an auto parts store) and install it in the slot.
Next, take the B-post off of the S4 alt. and swap it with the S5 alt's post. The ring terminals are different size, so matching the smaller post to your smaller S4 terminal is easiest. And that's it.
04-19-10, 09:03 PM
#17
HAILERS
Join Date: May 2001
Location: FORT WORTH, TEXAS,USA
Posts: 20,563
Likes: 0
Received 21 Likes
on
19 Posts
The REGULATOR of a series four has switched power going to it (turn key ON).
Series five REGULATOR has power on it 24/7. NOT switched power as on a series four.
IF the small plugs black/white wire has batt pwr when its disconnected from the alternator..........and you only get approx 12vdc out of the alternator when the engine is spinning it over (all plugs connected), then the regulator is kaput. The regulator is part of the alternators guts.
Series five REGULATOR has power on it 24/7. NOT switched power as on a series four.
IF the small plugs black/white wire has batt pwr when its disconnected from the alternator..........and you only get approx 12vdc out of the alternator when the engine is spinning it over (all plugs connected), then the regulator is kaput. The regulator is part of the alternators guts.
04-20-10, 05:15 PM
#19
Full Member
Thread Starter
iTrader: (4)
Join Date: Mar 2010
Location: Tallahassee
Posts: 237
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for all the help guys. I put the s5 alt in and battery holds charge at 14.4 volts. The only thing thats off is that when the key is to the on position all the warning lights arent on. I followed the diagram. I think I did something wrong somewhere. The only lights that come on are the washer fluid and the belts.
04-20-10, 07:37 PM
#20
HAILERS
Join Date: May 2001
Location: FORT WORTH, TEXAS,USA
Posts: 20,563
Likes: 0
Received 21 Likes
on
19 Posts
Sounds like you put the WHITE/black wire on the wrong terminal of the alternator.
You look into the jack on the alternator with the keyway on the top as you look at it. The WHITE/black wire goes on your right as you look into the alts elect jack.
You look into the jack on the alternator with the keyway on the top as you look at it. The WHITE/black wire goes on your right as you look into the alts elect jack.
04-21-10, 02:19 PM
#21
Full Member
Thread Starter
iTrader: (4)
Join Date: Mar 2010
Location: Tallahassee
Posts: 237
Likes: 0
Received 0 Likes
on
0 Posts
I switched the wires and still no lights. I have the white with blue stripe from back of alt to the white with black stripe wire into the harness. The lights still do not come on, onlys are the belts and the washer fluid and ebrake if I have it on. They were all coming on before I rewired. But im not sure if the cluster itself has gon bad since the clock isnt working.
04-21-10, 04:27 PM
#22
HAILERS
Join Date: May 2001
Location: FORT WORTH, TEXAS,USA
Posts: 20,563
Likes: 0
Received 21 Likes
on
19 Posts
It's like this. Take the plug/wires off the alt. Turn the key to ON. Put the WHITE/BLACK wire to ground. The warning lights will all come on.
Put the key to OFF and put the plug back on the alt. Turn the key to ON. Warning lights should all come on BECAUSE they should be getting a GROUND from the internals of the alts regulator.
So if the first step above worked and the second part did not...................part of the alt regulator circuit is toast.
Engine NOT running during the above steps.
To prove it, with the plug on the alt, backprobe the WHITE/BLACK wire with a meter. It should read approx 3vdc. If it reads more, like batt voltage......the regulator is toast ........well partially toast. Use as it and just forget all the warning lights ever coming on in the future.
Engine NOT running in the above check.
Put the key to OFF and put the plug back on the alt. Turn the key to ON. Warning lights should all come on BECAUSE they should be getting a GROUND from the internals of the alts regulator.
So if the first step above worked and the second part did not...................part of the alt regulator circuit is toast.
Engine NOT running during the above steps.
To prove it, with the plug on the alt, backprobe the WHITE/BLACK wire with a meter. It should read approx 3vdc. If it reads more, like batt voltage......the regulator is toast ........well partially toast. Use as it and just forget all the warning lights ever coming on in the future.
Engine NOT running in the above check.
04-21-10, 04:54 PM
#23
This is backwards. The W/B S4 wire connects to the W/B wire from the S5 plug. The W/L wire from the S5 plug connects to the new wire you ran to a 12V source. It should have worked with it the other way around, but now you may have damaged something.
04-21-10, 09:31 PM
#24
Full Member
Thread Starter
iTrader: (4)
Join Date: Mar 2010
Location: Tallahassee
Posts: 237
Likes: 0
Received 0 Likes
on
0 Posts
So, I shouldve taken the White with black stripe to L terminal, and caped off the Black with white stripe. Then took a wire to the S terminal wire on the s5 alternator and ran that to the main fuse block to a 30 amp fuse?
Im confused now. The battery is charging fine and by the time i got on to check the replies it waws too dark to try the troubleshooting for the lights to come on. Nothing is messed up from what I can tell, the battery is still holding over 14volts when running.
Im confused now. The battery is charging fine and by the time i got on to check the replies it waws too dark to try the troubleshooting for the lights to come on. Nothing is messed up from what I can tell, the battery is still holding over 14volts when running.