1G Charging system issue!! techs only please

[kamronman]

My battery is new. My alternator easily passed the bench output test. At idle my car's battery voltage is only 11.9 instead of 14.8 like usual. My brand new headlight bulbs burnt out about a week before my car's electrical died on the freeway while driving. I called a tech at the dealer and he says the voltage regulator on my alternator must be bad...Does anyone know any more about this than I do? I've done draw tests on both my negative and positive circut from battery and then from + to the alternator, there's no connection issues, blown links/fuses, and no corrosion. Someone please help me out..

 

[black_gst]

are you saying that your Alt passed one of those tester machines at an auto parts store? if so IMO those machines are junk. i have had them test and pass alternators and starters that were in fact bad. the best way to test an Alt is with it on the car.

if it fails the "on car test" replace it.

if you raise the rpm's does the Alt start charging? but at idle your running off your battery.

if the answer to this question is "yes" then it is the regulator in the Alt that is bad

 

[GRAVEDIGGER]

Like black_gst says, if it fails the on car test it's junk. If you are only seeing 11.9 volts at idle there IS a problem and you need to get another alternator.

 

[motorswapman]

There are two wires that run to voltage regulator on the alt. (its the two wire plug plugged into the alt.) trun your ign. on and make sure you are getting + &- to the regulator. That is what makes the alt. charge if your car is not sending voltage to the regulator that might be why the alt. passed the bench test but will not charge on your car.

 

[kamronman]

There are two wires that run to voltage regulator on the alt. (its the two wire plug plugged into the alt.) trun your ign. on and make sure you are getting + &- to the regulator. That is what makes the alt. charge if your car is not sending voltage to the regulator that might be why the alt. passed the bench test but will not charge on your car.

So you want me to use my DMM and prong each of those wires with the key on? What should i be looking for? Just some sort of reading?

 

[GRAVEDIGGER]

Yeah, he means to just check the two wires going to the voltage regulator. One should have 12volts (+) while the other should be a ground (-). If you have good power and ground there then the alternator is not doing its job. If you don't have power and ground then that could be your problem. Does that make sense?

 

[motorswapman]

Its just 2 wires it plugs into the alternator just plug the + of a tester into 1 end of the plug (the wiring harness side) and the - into the other end and turn the ign. to on. It should read 12v if it does not then it is not the alternator.

 

[kamronman]

Ok im in my car right now on the laptop. Before starting my car i tested for voltage on both those wires, i found 11.9 on the left wire of the plug, and 12.3 on the right one. Also, after starting my car and my voltage stayed between 12.0 and 11.9, i revved up to 5k a few times and No voltage increased or decreased, but it's barely firing! I can feel the misfire and my afr's are full lean as my ISC is struggling to keep the car on, vacuum=-8 while this is happening. If one of you guys is really concerned and you think you can help my out over the phone give me a call! 360-250-9995 name's Kamron

Ok im in my car right now on the laptop. Before starting my car i tested for voltage on both those wires, i found 11.9 on the left wire of the plug, and 12.3 on the right one. Also, after starting my car and my voltage stayed between 12.0 and 11.9, i revved up to 5k a few times and No voltage increased or decreased, but it's barely firing! I can feel the misfire and my afr's are full lean as my ISC is struggling to keep the car on, vacuum=-8 while this is happening. If one of you guys is really concerned and you think you can help my out over the phone give me a call! 360-250-9995 name's Kamron

Oh so put both lead into the same plug! With the key off i found 12.3 volts, with the key on i found -0.8V. This is with positive on one wire, the negative in the other wire of the same plug into the alternator. (while the plug is unplugged)

 

[motorswapman]

The alternator is the charging system problem the car may be running bad because it is not charging.

 

[kamronman]

Yeah the car's running horribly because it's a steady 11.9 volts while running, then when i shut it off the voltage goes back up to 2.2-2.3! ughh. You happen to know the cheapest possible way to find a working alternator and slap it on to verify that it's only the alternator? Like the junkyard has 2 non-turbo models with alternators, they are about 20$ there..Or I can get a napa refurbished one for 100$ and give them my oem core.. And i need to be driving asap

 

[GRAVEDIGGER]

Ok Kamron, I just went out to the garage and checked my wires to see what I was getting and here's what I got.
The white wire (larger of the two) has power when the key is off as well as when key is on. The black wire (smaller of the two) has ground when the key is off, but when the key is on it has power. You should be checking one wire at a time by inserting the positive (red lead) of your meter in the connector and the negative (black lead) of your meter to any good ground. Test it that way and see what you get.

 

[kamronman]

Yes, I'll post up all the specific key on key off results really quick:

Key off/White wire = 12.4V
Key off/Black wire = 0.0V

Key on/White wire = 12.3V/12.4V
Key on/Black wire = 11.3V

Key on/Both plugs (+ lead to white wire/- lead to black wire) = 0.9V
Key off/Both plugs = 11.9V

 

[GRAVEDIGGER]

Cool Those results are consistant with mine so I would bet the ranch that your wiring is all ok, the bench test is lying, and you need to replace that damn alternator.

 

[kamronman]

Cool Those results are consistant with mine so I would bet the ranch that your wiring is all ok, the bench test is lying, and you need to replace that damn alternator.

Ok! Thanks bro, really. Not many people have the patience to put that kind of effort into helping a random person!!

 

[GRAVEDIGGER]

No problem my man.

 

[luv2rallye]

Here's a good test for the 1g alt on the car. Off the car the only place that does a worthwhile test is an alt/starter repair shop (see yellow pages). They also are the best place to buy an alt or have yours repaired. Auto stores are the worst place to buy an alt (terrible quality and very unreliable) and have near worthless testers. They deliberately sell very poor quality alts at cheaper prices than everyone else to make a ton of money by outselling everybody, since nearly all americans buy only on price (and they just send it back to their supplier if it doesn't work so they lose nothing, not even shipping). But what good is their lifetime warranty and cheaper price when YOU have to replace their alt over and over and over. Just search this forum for all the problems people are having with auto store alts (especially Autozone).
http://www.dsmtuners.com/forums/art.../226323-2-minute-alternator-circuit-test.html

 

[dsm8883]

Here's a good test for the 1g alt on the car. Off the car the only place that does a worthwhile test is an alt/starter repair shop (see yellow pages). They also are the best place to buy an alt or have yours repaired. Auto stores are the worst place to buy an alt (terrible quality and very unreliable) and have near worthless testers. They deliberately sell very poor quality alts at cheaper prices than everyone else to make a ton of money by outselling everybody, since nearly all americans buy only on price (and they just send it back to their supplier if it doesn't work so they lose nothing, not even shipping). But what good is their lifetime warranty and cheaper price when YOU have to replace their alt over and over and over. Just search this forum for all the problems people are having with auto store alts (especially Autozone).
http://www.dsmtuners.com/forums/art.../226323-2-minute-alternator-circuit-test.html

So true it seems like every day people come into the shop and wonder why we do not sell autozone junk. People just buy what is cheaper and pay for it in the end. We test alt's after autozone has passed them and half fail with our tester on the car with all (loads) on. I really hate to see more autozones poping up and pushing more junk.

 

[kamronman]

Here's a good test for the 1g alt on the car. Off the car the only place that does a worthwhile test is an alt/starter repair shop (see yellow pages). They also are the best place to buy an alt or have yours repaired. Auto stores are the worst place to buy an alt (terrible quality and very unreliable) and have near worthless testers. They deliberately sell very poor quality alts at cheaper prices than everyone else to make a ton of money by outselling everybody, since nearly all americans buy only on price (and they just send it back to their supplier if it doesn't work so they lose nothing, not even shipping). But what good is their lifetime warranty and cheaper price when YOU have to replace their alt over and over and over. Just search this forum for all the problems people are having with auto store alts (especially Autozone).
http://www.dsmtuners.com/forums/art.../226323-2-minute-alternator-circuit-test.html

Thanks for the input I actually just saw an alternator/starter service shop open up locally, Instead of going straight to shucks tomorrow i'll bring my alternator to them and see if they can just rebuild it for cheap, or at least get me a new one. And that two minute test was pretty clever, but I did that exact thing today, if you look at my test results posted earlier. Determined my alternator is indeed bad.

I bought a new alternator today and put it on, it seems to be charging at 13.5-13.6 volts constant. Which still isn't usual for me. I have no voltage drops on any of my connections between the battery and alternator. Should I have a ground from the case to chassis?? I don't have one if i should.

(ed- No, the alternator is grounded by the long bolt that goes through the case and mount to the engine block)