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toofun
08-27-2005, 03:21 AM
Think I have a problem with my Alternator. Lately I have had to jump the car to get it to start. I thought it was the battery but was told it was my alternator. I started the car after driving it a long time on the highway at night. Disconnected the battery cable with the car running and the car stayed running, BUT the minute I put my head lights on the car died flat. So I reconnected the battery cable,jumped started the car again and had a buddy of mine put a volt meter on the car. It read 12.5 volts at the battery with the car running. If you revved the motor then it would jump to 12.8 BUT NO MORE. My buddy says that the alternator is not charging the battery and since the car died with the cable disconnected when you turn the lights on.

Funny thing is that when I took the car to the local Auto Zone they SPUN it on their machine to test it. The computer report came back PASSED on all the tests run. The battery is BRAND NEW!! I noticed that I had this problem when I let the battery run completely dead one day. I jump started the car and got it running again, drove it a long long time then shut it down for five minutes and turned the key and it started. But now it is at the point where the car wont even turn over when I go out to start it. Could the battery be dead? Could the ALTERNATOR still be bad? Why isnt it charging the battery with the car running? Are there other areas I should be checking? Sorry for all the questions but I am not electrically inclined at all.

Thanks in advance

Mark
TOOFUN

toofun
08-27-2005, 03:44 AM
I believe this alternator is the 60 amp type. It is all chromed and fits well with the rest of the engine bay. I forgot to mention also that I am running a small power amp for the radio system and an electric fan as well. I also upgraded my distributer to a high powered MSD model. Both feeds for the power amp and the electric fan run directly to the battery. with a fuse link between them. Could it be possible that I dont have enough alternator to run this car?

68protouring454
08-27-2005, 03:51 AM
i would check wiring and also check voltage at back of alternator, you should have at least 13.8 volts or so, with alt usually being 14-14.5 while running, check at back of alternator that will say if alt is bad or wiring is loose or bad
jake

toofun
08-27-2005, 07:09 AM
Thanks Jake,

Will do, Someone on the other site said that it could be the voltage regulator or the terminals on the horn relay? How would I go about checking that? I guess I need a systematic approach to isolate the problem. You know like if you do this and this happens then you can eliminate that...etc...

Thanks In advance to all

Mark
TOOFUN

Sparky
08-27-2005, 11:03 AM
What year and type of vehicle do you have? This would help us better point you in a direction.
From what you have posted, it sounds like a couple things could be at fault.

As Jake mentioned, checking the wiring and output at the Alternator is a good start. You would need a Digital Voltmeter, (DVOM) like a Fluke 83 or 87. Set the meter to DC Voltage, with the vehicle running at an idle, check the output at the back of the alternator and at the battery. Like Jake said, you should be around 13 .8 at the Battery and about the same at the Alternator.
Increasing engine speed should make the voltage go up to around 14.5 volts.

You should also check the Voltage Regulator, make sure the connections are clean.

There is a full test procedure on how to check the Voltage Regulator here,
http://www.users.bigpond.com/jack_stands/automotive_advice/auto_electric/auto_elec_2.html
One of the easiest test, is to Jump Terminlals B (Battery, Red wire) & F (Field, Blue wire) at an idle.
If the the Alternator voltage goes up, then you possibly have a bad Regulator.
But you should run through the other test first and make sure you have the proper signals on the other wires.

The big wires at the horn relay are actually a junction point, for the inside car power. One of them should be Battery Power and the other runs into the car, to the Fuse Box. Check these and make sure they're not corroded, broken, etc.

The other nice advancemnt to come about is a one wire alternator. You can get these from Power Master http://www.powermastermotorsports.com/
and East Coast electric http://www.ecae.com/
A one wire alternator can make life a lot simpler with the charging system. One wire form the alternator to the battery and that's it.

On another note, reading through your post with all the accessories you have on the car, you may want to consider something over a 100 amps.

I hope this helps,
Sparky

gmachinz
08-27-2005, 11:04 AM
I would bet the alternator is bad. Autozone's newer testers like that don't give you a readout of the amperage which would be nice. Sure, it can be testing good, but at what amperage output? Also, the charging system is not designed to charge a battery, only to maintain its charge. So, if you are running your accessories directly off the battery, I suspect the alternator cannot keep the charge up. The alternator will do a better job of running your fan for example if you use your +12V buss bar on your horn relay and route that to a relay for a power supply. Really though to take full advantage of modern HO electrical components, I would recommend upgrading to a 94-140 amp CS design alt. But, this is assuming you have no other electrical problems. I'd replace the headlight switch first just as a start. There is so much voltage drop in OE wiring from those years that I'd consider totally re-wiring it anyway. -Jabin

Before making the switch to a one-wire alternator, be sure to research its drawbacks (and there are several...) on www.madelectrical.com and you'll probably stay with a three-wire system for a more durable design. Focus on what the author says about voltage sensing and you'll see the one-wire's biggest drawback.

zbugger
08-28-2005, 02:53 PM
First of all, you are going to want to upgrade to an alternator of at least 105 amps. Your ignition and stereo will pull power from the charging system. Also, I'd recommend staying away from the one wire alternator. I ran one, and now I'm swapping back to a three wire. I was constantly annoyed at night when the thing would basically shut off because my idle rpm was low. I'd have to hold the rpm's up to keep it on. It sucked for me.

toofun
09-07-2005, 03:39 AM
First of all thanks to everyone on the answers they gave. I had some other issues this week to take care of and could not get to my alternator.

Anyways, I got a brand new battery from autozone(they replaced the other one reluctantly after I told them it would not hold the charge). So I started the car and checked the voltage at the battery. 13.7 volts. Then I checked the voltage at the voltage regulator. 13.4 volts I then put the head lights on in the car and with the battery connected checked the voltage at the battery and it dropped down to 7.4 volts!!!! If I take the positive cable off the car with the car running and put the negative rod on the negative side of the battery and the positive rod from the meter on the positive disconnected CABLE it reads 13.6. But the minute I turn either the electric fan OR the headlights on... the car stops dead.

So My buddy and I seem to think two things are wrong. 1. the alternator is not working to its potential under load, and 2. I dont have enough alternator to run things like my HEI, ELECTRIC FAN AND STEREO AMP in my car. What do you all think?

68protouring454
09-07-2005, 04:38 AM
sounds like somethings bad,alternator would not pull that low with just that stuff, but if you jneed a new one you might as well get at least 100 amp alt

toofun
09-07-2005, 04:59 AM
OK,

Let me ask you this. If I get a more powerful alternator, would I need to change anything in the electrical system? Would it hurt anything? Is there such a thing as having too much of an alternator? Also, I am guessing that I have a three wire setup since I have more than one wire coming out of the back of the alternator. How do you tell if you have an external regulator or internal? I am assuming that I would not have an external regulator if I had an internal? Should I switch to an internal one and if I do what would I do with the voltage regulator that is external now? I am not very electrical as I said before so any help would be appreciated.

Thanks
Mark

gmachinz
09-08-2005, 01:46 PM
Toofun, you may need to trace the wiring from your alternator to make sure it does not still run to your external reg. which is factory mounted on the driver's side radiator support. If you want to switch to an internally regulated alternator, simply loop the blue and brown wires together coming from your OE wiring harness to the regulator and then cap the white and orange. You can now remove the OE external regulator. Now, cap the white wire at the alternator loom and run a 12-gauge wire in its place coming from the alternator connector to a +12V source. you can either loop it back to the charge post or route it to a junction to act as common connection for HO electrical accessories. If you have any questions or need clarification, email me and I'll help you out. -Jabin

MarkM66
09-09-2005, 06:25 AM
FWIW, I'm having similar problems. I'm running a Power Master 1-wire 100 amp alt. Going down the road with nothing on, it runs right at or a little over 14 volts. As soon as I turn the lights on, it goes down to around 12. Lights and electric fans, below 12.

If the factory alt. could keep up just fine with everything on, this alt. should do it no sweat.

toofun
09-09-2005, 07:47 AM
Dont know if this will help but many people DONT recommend the one wire application. Too many problems and not as reliable as the three wire setup. Just what Ive heard. Do a search in this section on one wire vs three wire and you should get alot of info on this.

Mark
TOOFUN

gmachinz
09-09-2005, 01:36 PM
My experience with one-wire alternators is not favorable. I prefer my standard upgrade to a 6" CS cased 140-amp alternator. I have not had any problems or warranty issues with it and I've sold about 25 and installed maybe 15 by now-some I've built to provide 200-amps! Granted, those are mainly stereo competition vehicles but that's as high as I can go with that style of case.. -Jabin

MarkM66
09-13-2005, 07:20 AM
Yeah, I've read all about that. I would of went with a CS style, but it wouldn't of fit the look I was going for.

So far it's working fine, it charging enough to start the car. And that's all the really matters to me.

gmachinz
09-13-2005, 05:57 PM
The biggest problem with high amp alternators is the amount of heat they generate. I've worked out an arrangement with a local alternator shop to supply me with all the internals to bump the output up. I mount the additional diodes on the outside and make an aluminum cover to hide them. -Jabin