You're having all the problems I was having, I'm a tech by trade and I never have problems with silverado alternators either, the OEM seems to very rarely fail and when they do and I slap an aftermarket one on they don't come back. Why? No idea, i'd have to find a competent rebuilder to test each failure and come up with an answer as to what keeps failing. But something is being used that's common in the aftermarket rebuilds/new alternators and I tried every flavor that NAPA offered, autozone, oreilly and two different parts suppliers and the only thing that worked was an OEM used silverado unit. I suspect an OEM camaro unit would do fine, but good luck finding one that is still good vs the millions of silverado units out there.

If you're exciter wire is acting up you'll get an L terminal code and a check engine light. I hunted that too for a while and it turned out to be the alternator every time. I even tried the big 3 and had no luck.

By the way, the ones I had fail, would test fine on a bench too. It's when they get super hot under the hood on a summer day that the voltage drops out, and you can't simulate that on a bench. I went round and round with the NAPA manager trying to explain this because they refused to give me a refund, they did eventually.

You're like me, you're checking everything testing everything and coming up with nothing, it all leads back to a crap alternator. I wen't through like 10 of them man, I was going crazy and chasing everything all the while, just **** alternators.

 

I'm leaning towards the Remy style not being compatible with the 1 wire pin. Next one I'm going with a 105 amp bosch from Silverado

I have no problem swapping them, the a.c. Delco reman is the same price as my gold, I'll try that next since it will be a free trade

It's technically not failing, and the big 3 upgrade has definitely helped my radiator fans. 30 minutes idling with a.c. on and the needle was solid at 180






Just for fun

 

Keep doing everything but putting a quality alternator on it and you'll keep putting alternators on it.

You say it's not failing, yet it's not charging. Also, your factory alternator that was a quality unit never had a problem running the fans without the big 3, yet your big truck alternator needs help. All that sounds like a big pile of fail to me.

Why do a 105 when a 145 fits and works and keeps everything happier?

You'll get tired of ******* with it eventually and bite the bullet like I did. But feel free to come back and say you've got one that works great and then in 1-2 months post again that it took a **** lol. I've been there.

 

you're correct the original never failed the alternator test, but it had wildly fluctuating voltage. The fans, I swapped the radiator for a dual core and that's when it started getting warmer than normal

Did you ever try the Delco brand reman?

 

I'm dealing with this bullshit also. During my build, I noticed the bearings on my original oem f body alternator were noisy. Deciding to be proactive, I ordered a reman delco from summit. Within the first 50 miles it took a ****. Being that it had been about 6 months since purchase, I decided to forego the hassle of dealing with summit for a refund/exchange. Whent down to autozone and picked up a lifetime warranty reman unit. It whent about 150 miles before tossing it's cookies. I spoke with Steve Williams @ tuned by frost about the issue. He didn't right out say it, but his insinuation was that reman f body alternators suck dick.
My original suspicion was that my car was the problem, as it's a swapped vehicle and i did a ton of wiring. However I began to think these alternators were the problem. With having a lifetime warranty on the autozone unit, I decided to try one more. Well f..k me, the 3rd one took a **** around the 150 mile mark, immediately following short throttle stab. I also discovered that it would charge until it started to get some heat into it. After hot it was dead, if let to cool it would charge again....

At that point, I started doing some reading. I came across this thread. Thank you to the OP for sharing your experience. I took the last alternator back to autozone and asked for a refund. The dude put it on the tester, brings it back and says "it's fine, you need to diagnose the car". After a lengthy discussion he did issue my refund.
I recently installed a 130 amp truck alternator in conjunction with Big 3. I don't have results yet but will update if it fails again. Just thought I'd add my experiences to this discussion.

 

Yeah mine has that same problem even with the truck alternator, rebuilt or brand new my auto parts store alternator fails the diode test.

So he's saying my options are junkyard oem or nothing.

 

yep. Mine is junkyard.

 

wph351 - I had the exact same experience. It would pass a bench test and when heat under the hood built up it would stop charging and work again after sitting over night. I had one die in literally less than 5 miles/5 minutes of putting it on. I kept checking the car, the wiring, the exciter wire, the amp draw etc etc etc. The only thing that changed between having 0 issues and having nothing but issues was I changed out my OEM alternator after my power steering pump leaked on it and I got worried it would cause it to fail, it was still working when I took it off, and then all the problems started. Logic would say it was the alternator but after 1 or 2 you start thinking it's the car, imagine my frustration and confusion after 10 of them. The junkyard alternator survived for years until the car was totaled by someone that bought the car from someone I sold it to.

Chrysler kid - I'm saying I tried everything you tried and the only thing that worked was a junkyard alternator, and in this thread you will find pages and pages of people using a junkyard alternator with zero issues. My OEM alternator did have a lot of voltage variation as well, the replacements held steady for a day or two until they bit the dust. My longest lasting alternator worked for 2 weeks then stopped charging when hot. That's the alternator that got me into an altercation with the NAPA manager when he wouldn't refund my money lol. I got the refund though.

To everyone - each unit would fail the first time I would make a pull, my rev limiter was at 6800 and not one of them took a 6800 rpm pull. The $40 junkyard alt took it EVERYDAY even with a system blaring and a/c running in 100 degree weather.

I now have a junkyard 145 amp on my truck because it came with the standard 105. I have added factory electric fans that pull around 40 amps and I have a real deal 2500 watt amp with OFC 0/1 gauge wiring pulling almost 150 amps and with all that the alternator is as happy as can be.

 

I think you are touching on something important here. The alternators i had seemed to hold up ok if i was doing a pull from a roll, however they seemed to fail within short order after a quick RPM spike. Example: The third one I fried was just after dropping off a buddy. He wanted some rubber in his driveway. So I did a quick throttle stab burnout in first. It will normally go to 6500 almost instantly in that scenario, and it did. Less than a mile up the road the needle started to flicker. TOAST. Now, I don't recall the exact circumstances leading up to the first 2 failures, but I feel comfortable saying it was shortly after beating on the car. Because I always beat on the car. This leads me to wonder if these alternators are ok at stock power levels, but maybe something about the rapid rpm increase of a modded motor makes them fail?

Nevertheless, I really appreciate you sharing your solution. I'd be ripping this car apart trying to figure this out. I just got the car back on the ground this evening after installing a 130 amp truck alternator and Big 3. Made 3 hard hits, did a few quick stab burnouts. The alternator held up fine.

 

Mine are always rpm dependent as well though I never see less than 12.6 on a hot day long drive, these are brand new out of box alternator. My theory is the new ones leak voltage and I may try running one of my old cables from the case to ground to the chassis. My theory being the bracket on the trucks is a larger ground than the fbody.

That being said will this alternator work. Trying to find a southern alternator that isn't rusted on ebay
http://m.ebay.com/itm/ALTERNATOR-FIT...257Ciid%253A11

 

I made one last a little over a week once and I took the car to the track. The alternator failed first pass. Now my car was only a bolt on car, It only ran 6.7 in the 1/8th it wasn't what most would deem fast. I drove it up to 600 miles a week so it was just a fun daily driver is all. Glad to hear it's working out and glad to help, i've been stuck many times wishing someone had the answer so I know how it feels. Did you do a junkyard alt or a new one?

12.6 is too low, should be able to maintain higher than that. You and I did the same thing... "the alternator keeps failing maybe it's this maybe it's that maybe if I try this it'll help"

You have to go back to the basics here and evaluate the total situation. For the first probably 10 years of your cars life it never had charging problems, and the ONLY THING THAT CHANGED is you put a different alternator on it. Therefore, if you put another quality alternator on it the car will go back to doing what it previously did, working properly. We get caught up in making the problem more complex than it is and end up on bunny trails. I do it at work all the time, I go for the complex and forget to bring it back to a simplistic view.

That alternator will bolt up but it's a 2 wire instead of a 4 wire so you'll need to convert to the 2 wire connector end and google how to use a 2 wire alternator on a 4 wire car. I'd just get a 4 wire from a 99-04 and keep it simple.

I get my alternators from LKQ, I put a 145 amp on my truck recently, used from LKQ it was $60 and looked like ****. I cleaned it with a wire brush and drilled holes in the rear plastic cover to help with cooling. I even painted the pulley. All of this did just made it pretty, didn't help the output, but I work the **** out of this alternator and it has help up great.

Also I like the junkyard alternator not only because they work better, but they are only $60 and I can buy 3 for what 1 costs at autozone and they last longer. I can have a lifetime supply for $180 and if I fry one, no big deal it was $60 instead of $200 and having to exchange it all the damn time be stuck on the side of the road and argue with managers that won't warranty it because "it tested good on the bench"

 

FWIW if your using a Optima battery NEVER EVER use a battery maintainer on one, they do not like trickle charging. (The manufacturer used to say this as well. ) Optimas like to be hard charged, 12A minimum on a big one is about right.. If you have to park it, then use a battery disconnect switch.

I use a home alarm system battery to store the car to maintain the computer and electronics settings.. But disconnect the optima.. AGM batteries in general need a pulse charger on a timer more than a maintainer..

 

Bought a junkyard one off ebay for around 50 bucks. It was advertised as a kg3, however it is stamped with some random numbers that end in 130A. Im Not 100% sure what it is, but it bolted up with no issue and is working well.

 

Side note, my BMW has a very similar alternator,, and has a separate hose that runs forward, to the core support, its a CAI for the alternator.. Because on the car its buried behind a ton of stuff that blocks air flow. Wonder if a "brake duct" would help...

 

I think you hit on a major reason for the reman failures, and many other alternator failures. HEAT. Run some fresh air past them and they will live by staying cooler. If it has to live in a stagnant air zone, plus next to or below an exhaust manifold/header, it is living in hell. Electronics don't like intense heat.

 

Only caveat there is the OEM alternator lived in the same environment no problem. So there IS a problem with the aftermarket alternators and you should not have to alter your vehicle for a direct replacement part to function.



That being said, it's always a good idea to keep electronics cool and I agree especially with alternators, I drilled my rear plastic cover to allow for more cooling but I'm pushing my alternator way beyond what it should be pushed so I wanted to help it as much as possible.

There are several makes of cars with alternator cooling ducts out there, on some fords there is a duct that goes from the radiator cooling fan over and across the engine to the alternator.

But if you have a car that doesn't come with alternator cooling, the OEM alternator survived just fine and the only way an aftermarket will survive in the same environment is with cooling, then you are putting a band aid on the real problem.

 

Then there has got to be a shortcut the rebuilders are taking that compromises their alternators. Have you tracked down the EXACT component(s) that are failing?

 

I wish I could tell you why only used ones will work, but I can't

When the 140amp alternator was attached to a 6 gauge negative ground to the case things got weird, the alternator would act like it wanted to kick into high output but would harshly dim the lights and buck the motor. My best guess is the trucks have a stronger ground on the mounting bracket, and a better ground to the frame than the fbody


The same new gold alternator works flawless in my truck, and the old 105 amp from the truck works flawless in the camaro

Out with the new








In with the old








And the new one in my base.model 2500 4x4 truck with crank windows








This **** is retarded

 

IF it is just a matter of grounds, that's an easy fix! HEAVY wire WELL-CONNECTED between EVERYTHING that matters. LOL. Maybe not as easy as it sounds, but still....

 

No it's not that simple.

The parts store 140 amp max output cold peak voltage with a 6 gauge ground to the case peak output was 13.9 and dipped to 13.4 hot with a.c. on and lights on and was still dropping to 13.2. It was a .4 volt improvement from before but still a drastic drop

Truck used peak cold is 14.1 peak cold and 13.5 constant engine warm a.c. on. I'll perform an alternator test tomorrow but the used 105 amp shows no flickering check gauges light under WOT like the new one which would still show 12.9 at WOT but trigger check gauges.

A side note grounding the front bracket of the alternator triggered a much more drastic click from my relays, and a strong noise from my fuel pump and has cured my hard start issue

The old used truck alternator is more receptive to the exciter wire from the ecu. That's just how it is, not sure why

(I just swapped everything tonight and went on short drives each time, I'll test the 105amp used one from my truck tomorrow at my store to verify correct operation)


Picture of my old negative ground cable pulled when I did the big 3 upgrade, installed to the alternator bracket