Still have Alternator problems - suddenly I hate this car

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Q451990
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So I remote started the car to let it warm up for a few minutes... walked up to it and noticed that the licence plate lamps looked a kind of dim. Got in and noticed that the dash lamps were dim. Got out my trusty meter and found the voltage at the battery to be at about 9VDC at idle.

The battery in the car is about two years old and has about 2,700 miles in service... yeah garage queen.

While I had the alternator out of the car, I charged the battery overnight with a good battery charger and figured it was OK. It pulled several amps when I started charging it, and was down to about 1 when I took it off. When I put everything back together, the battery held at 12VDC or so during starting and then showed 14.2VDC at idle.

I took the battery out of my truck and tried it in the Q and the new alternator is toast... Idles at about 12VDC and falling. I'm pretty pissed right now.

So I guess I'll find out tomorrow if my battery is bad. I'll take it to AutoZone and see what their magical battery machine says. Maybe there's a bad cell in there that ate my new alternator. Unfortunately there's no warranty on the alternator since I bought it from a guy who bought it new for a spare four years ago, and then sold his Q before using it.

My back hurts already.

:mad: :cry: :facepalm: :mad: :cry: :facepalm:


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Q451990
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So AutoZone charged the battery and said it checks good. No bad cells - everything OK. Old alternator tests bad... their systems says it's a bad voltage regulator. For sh--ts and giggles I brought the car back with the freshly charged battery and new bad alternator and let them check it with their mobile tester, and the new alternator tests the same way... bad voltage regulator... output 12.something volts.

Anything that commonly eats voltage regulators?

Heath

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Q451990
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Well, I pulled the old alternator apart that came out of my car. It turns out that my diode assembly was bad - not the voltage regulator. I took it back to AutoZone and it passed with flying colors - which brought up the question "So if if your equipment said my alternator had a bad voltage regulator and good diodes, but it was wrong - could it have been wrong about my battery being good?" They agreed to give me a new battery - just to save me from worrying about it.

Is it possible for a battery to fail intermittently in a way that causes a cell or two to short out or put an undue load on the alternator - frying the diodes in the alternator - and then "heal" itself? Maybe when cornering or something? It's tied down properly and all of that...

Heath

qship96
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I dont know, but with a brand new battery,I would put in a brand new alternator next.....that way the whole charging/storing system is new and one potentially faulty component cant drag down the other.

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Lokim
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Remember these guys?

http://www.qualitypowerauto.com/catalog.php?item=205

They told me if I ship an old alternator to them they'll rebuild it for $195 with an upgrade to 200 amps including return shipping.

See below for the text of my emails to and from them:

The regulator has a high cutout point of 14.7 volts. This means that the highest voltage will be 14.7V. Voltage will vary in the system depending on the output ratio of the alternator. When amperage goes up, voltage goes down and vice versa. Voltage rarely remains constant when you have heavy loads such as with a stereo system. The best way to keep voltage higher is to use and alternator that is rated much higher than the load demand that you need.

Quality Power
31510 Yucaipa Blvd.
Yucaipa, CA 92399
(909) 794-1600

In a message dated 9/2/2011 7:26:29 A.M. Pacific Daylight Time, [email protected] writes:
I forgot to ask, do you guys set the voltage regulator at 14.4? Can we tweak it to 14.5?

Thanks!
-Mike
----- Original Message -----
From: [email protected]
To: [email protected]
Sent: Monday, August 22, 2011 2:21 PM
Subject: Re: 1994 Q45 alternator upgrade


If you would like to ship us your alternator we can upgrade it to 200 amp (including bearings, brushes, etc) for $195.00. You would be responsible for shipping it to us and we would include regular ground shipping back to you in the continental US. Our 200 amp alternator will provide about 110 amp at idle and should reach max output by 1600 - 1800 engine RPM. These numbers are from our testing at a 750 RPM idle with a 3:1 pulley ratio. You numbers could be slightly different depending on your idle speed and pulley ratio. We have no problems with the cooling at that amperage.

Quality Power
31510 Yucaipa Blvd.
Yucaipa, CA 92399
(909) 794-1600

In a message dated 8/20/2011 9:47:06 P.M. Pacific Daylight Time, [email protected] writes:
I would like to send in my factory alternator from my 94 Infiniti Q45 base model for a rebuild and amperage boost. I would like to get between 180-220 amps, and would like to know what amperages would be available at what rpms.

I would prefer ALL serviceable components replaced, including bearings. I am also concerned about adequate cooling for the assembly, so if you could detail how that would be addressed I would appreciate it.

Turnaround time is not critical, as I will be sending you a used unit that is not in the car.

Please send price and specifics as to what you can do for me.

Thanks!

-Mike

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elwesso
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qship96 wrote:I dont know, but with a brand new battery,I would put in a brand new alternator next.....that way the whole charging/storing system is new and one potentially faulty component cant drag down the other.
I tend to agree with this too.

I'm not inclined to think its a battery issue personally. So unless I'm missing something did you replace the diodes in the alternator?

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Q451990
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qship96 wrote:I dont know, but with a brand new battery,I would put in a brand new alternator next.....that way the whole charging/storing system is new and one potentially faulty component cant drag down the other.
Ideally, yes. Let's just say real estate isn't what it used to be, so I'm not sure that I'm going to put yet another new alternator in there at this point though.

I just did that with poor results and with a battery with no real evidence that it was bad. I will probably pull the harness and check it to make sure there's no corrosion or damage that I haven't found already - but everything looks good in that regard.

I found this site to be very informative, so I think I'll go through his process of looking for excessive voltage drop on the cables between the alternator and battery - although unfortunately that requires a working alternator.

http://www.aa1car.com/library/charging_checks.htm

Heath

qship96
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As a Realtor myself, I totally understand and agree with you! Not sure the market will ever be as healthy as it once was.While you certainly would need a functioning alternator to check for voltage drop through the wiring,you can measure resistance through the circuit w/o, which should indicate any wiring deficiencies.Maybe replacing the diodes on present alt will solve problems if the rest of the alt is newly rebuilt as you indicated.......they probably did not replace diodes during the rebuild if they checked out OK.....which of course,means they were old and tired, yet still functional at the time of the rebuild.....and died soon after,on you.

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Q451990
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I don't know if diodes can get "tired" or not. I guess everything has a useful life - but I don't know if it's like a board that's either broken or not - or a light bulb that has so many hours before the filament burns through...

qship96
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either way, you need a new diode pack at the minimum. Maybe a local alternator rebuilder could look it over and give it a clean bill of health before you spend the time reinstalling it.

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Skibane
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Q451990 wrote:Is it possible for a battery to fail intermittently in a way that causes a cell or two to short out or put an undue load on the alternator - frying the diodes in the alternator - and then "heal" itself?
Alternators are a lot more forgiving of massive overloads than most folks give them credit for.

By design, most alternators are self-protecting - They automatically limit their maximum output current. Producing a lot of current for a long period of time makes them run hotter (which ultimately reduces their lifespan) - but typically, they aren't "fried" by one brief overload.

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Q451990
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So do you think I just got a "dud" and I'm likely to put another alternator in and be fine?

Heath

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djwarner
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The charging system consists of a battery, regulator, alternator, and wiring. For cars our age, you can't rule out corrosion inside the wires. Usually this occurs where two different metals are in contact like steel terminals crimped onto copper wires. In particular, there is a wire running from the positive terminal of the battery to the regulator that tells the regulator exactly how much voltage is reaching the battery. A second place to look is high resistance in the ground wires anywhere in the system. The voltage drop in the ground wire adds to the voltage of the battery as it appears to the regulator. So while the correct voltage is commanded by the regulator, after the ground wire voltage drop, there's not enough to charge the battery.

When examining for corroded wires, look for wires that are stiffer than they should be indicating corrosion under the insulation. An ohmmeter should indicate less than an ohm for most wires.

Yes, you could have gotten a defective alternator from the rebuilder. A small percentage of all semiconductors are subject to what is known as "infantile death" due to contamination during the manufacturing process. In fact most warranties specify a given failure rate after a successful 100 hours of "burn in".

When I was an airborne electronics technician in the Air Force, getting a defective part from the repair depot always lead to weeping and gnashing of teeth - especially when the replacement failed in exactly the same way as the original failed component.

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Q451990 wrote:So do you think I just got a "dud" and I'm likely to put another alternator in and be fine?
Well, now - I wouldn't go THAT far... :biggrin:

I just think that an intermittently-shorted battery probably isn't the culprit.

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Q451990 wrote:So do you think I just got a "dud" and I'm likely to put another alternator in and be fine?

Heath
You know, I had the exact same problem when I changed my alt. out., I went ahead and got a new battery when I re-did the alt., I also rechecked all my grounds, cleaned them up,etc.; then everything was fine. I was hating my car at the time as well, but this too will pass...

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Q451990
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Good to know. I'm thinking I'll pull the positive and negative harnesses and check them out really good. Really go over everything closely. There's always the possibility that I just got a dud for my replacement alternator.

It's one of those things that I think I'm best off cooling down for another week or so before I tear into it.

Heath

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i would change out the batt cables while your in there. They don't last forever, I replaced my 84' Z's cables in 1995 and they need to be replaced again....if your keeping the car for a lot longer time it is a good investment.

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BadQ45t wrote:i would change out the batt cables while your in there. They don't last forever, I replaced my 84' Z's cables in 1995 and they need to be replaced again....if your keeping the car for a lot longer time it is a good investment.
Another good idea. I changed mine out a few years back, but I notice it seems to help, cleaning your grounds every so often. Changed out the cheesy battery connections as well.

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Q451990
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Update on this a mere 5 months later. I finally swapped in my old alternator with a working diode pack and new bearings. I checked the cables, and they ohmed out at something like .01 or .02 ohms. I don't know how else to check them except visually, and they seem to be fine from that standpoint. There's no way to get a meter probe on the positive connection with the car assembled... I was going to do this guy's voltage drop test - but it's just not possible on the positive side.

http://www.aa1car.com/library/charging_checks.htm

I did check it between the fuse block (where the cable comes in from the alternator) and the battery, and from the alternator case to the negative terminal for the negative side. Everything checked out nicely.

For those of you who have been following along from the beginning, I pulled my "Genuine Hitachi made in Japan" alternator apart, and I'm fairly certain I got hosed on that deal. Several parts in there are marked "TRANSCO-CN" which appears to be an aftermarket parts supplier producing "oem equivalent" parts out of China. There are two wires that go between the rotor and one of the brushes that apparently didn't get tucked in and were rubbed between the stator and rotor, causing it's failure in 3 days. Cheap Chinese crap that I think got sold to a former NICO member by a parts supplier in a Hitachi box. Either way I feel more confident that the alternator didn't fail because of something else in my electrical system.

I'll post pictures later.

AutoZone reluctantly swapped out my "checks good" battery for a new one. I also replaced the lines to my external transmission cooler, put in new low pressure p/s lines (the two from the reservoir), and changed the oil.

It's still on jack stands... next projects are a differential oil change and hopefully installing the active suspension front and rear bars!

Heath

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You will be rewarded. Keep going and drive it a little more often.

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Q451990
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Yeah really... I'm looking forward to it. Just washed up after today's fun of installing the active bars on the front and back, and changing the differential oil.

Now all I need to do is retorque the sway bar hardware on the ground, top off fluids, etc. I'm going to make a point to drive it enough to at least justify changing the oil by mileage... :D

Heath

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Congratulations! Good to know you are back on the road.

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Q451990
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Wish I had done the A bars years ago. It's weird... you feel the back of the car shift just a little, then the bar tips in. I felt the front get a little squirmy when I got too aggressive on a curvy on ramp last night. It's going to take a while to relearn the car. Not to mention essentially 8 months that I didn't drive it isn't helping much.

Heath

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That is like mine not being driven for an extended period of time. I really didn't start driving it until long after I had replaced struts, bushings, and anti-sway bar upgrade along with with 18" wheels. I can't remember what it was like before those upgrades.


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