StealthFRC

im trying to replace an alternator that i feel is on its way out.
i ordered a remanufactured unit thru auto zone. its a 110 amp unit. my car is a 99.
with the old unit i never got any codes. now with the new one i get a charge system fault on start up and it will not charge, if i rev it to 2-2.5k it will start to charge.

ive been reading on this and it seems people get this if they try and use a higher rated alternator like the 145amp or higher. seems im having the issue with a 110 unit.

i brought the new alternator to auto zone for them to test to see if it was marked wrong and it is indeed testing at 110 amp. i still had them order a new one to try but it will not be here till tomorrow.

any input from any of the electrical guys on this forum?

Pounder

You can make all the stickies in the world but if you don't read them = worthless !!!!!

73Corvette

Hope you kept your old alternator...

Macleod52

I wonder what happens to all the people who gave up their cores. Do they ever get their issue fixed or do they just keep driving around with the error message?

GCG

popshumphrey

Stealth - wondering what your resolution is? Saw the alternator at Auto Zone as well, and of course they say it will work.... So I am wondering about your resolution of your codes.

73Corvette

It WON'T work! Read the sticky POPS...save yourself some headache and get your OEM one rebuilt...

https://www.corvetteforum.com/forums...nd-issues.html

RIKKI Z-06

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StealthFRC

of course i kept mine lol. i did read that sticky, dont remember it stating that there are none that work. i also read that a member was able to get a unit from auto zone and it was plug and play.

GCG

What are the symptoms that make you think it is going bad?

StealthFRC

inconstant charging and at higher rpm. im not positive its the alternator tho. the car does have a lot of add ons like meth pump, external fuel pump, stereo, spal fans etc so it may just be to much for it to handle, id love to just get a alternator rated for more but obviously its not that easy lol.

i plan to bring my alternator with me to auto zone tomorrow and having them test it while i return the other one they gave me.

popshumphrey

I read it and not sure it's alternator anyway.

popshumphrey

Keep us, or me posted on what you do.

Macleod52

Please, read the thread that was posed a few messages up. I will make it easier and post it again below.

https://www.corvetteforum.com/forums...nd-issues.html

You state you get the charge system fault. It is your alternator. Plain and simple. No doubt about it. How do we know? Because you bought an alternator at Auto Zone and you get the charge system fault. Oh, and because this has been discussed 1000 times.

.....and because in that thread it states the following:
This sounds exactly like what you are describing. Just do yourself a favor and return the alternator back to Auto Zone. Then have your original alternator rebuilt.

GCG

Have you checked the alternator-starter-battery connection path?

Go to the starter solenoid and check the main connection for burnt, corroded or loose wires. That is where the starter, alternator and battery connect together and it is often the cause of charging issues.

zrtman1

I am having same issue.. I data log voltage and it is all over the place. Voltage seems to drop as underhood temps rise (like alt gets heat soaked). I am NOT getting any codes, but will see voltage on DIC 12.5-12.9v after heak soak at 1500-2000rpm driving down road. A few times as low as 12.3 which is about 12.6 at battery. On startup it is 13.4v ish when cold. There is roughly .3v drop between battery and DIC (using multimeter on battery).

All of my connections are clean - did engine swap and were cleaned/inspected. **My starter to alt lead had corrosion up inside factory heat shirk (looked fine until I moved it to clean it.. felt 'crunchy' and sure enough it was pretty green inside). This is on a southern car with no road salt etc. I put on a new fusible link and lug (can buy exact fusible link from summit). Eventually I plan on eliminating this lead and running heavier gauge from alt to positive common by the battery (with correct fusible link/wire or a slow blow fuse of correct amperage).

I was wondering if key switch contacts need cleaning or if it would help (Bill Curlee excellent thread).

I am not having any starting issues - but it is concerning. My F350 charges at 14.2v and will settle to 13.5 (driving down road) once warmed up/been driven awhile.

I thought the advanced auto parts alternator worked correctly as replacement?

StealthFRC

my original alternator DOES NOT GIVE ME A CODE. just the auto zone one does.
i never gave them my original for a core....

i always get a chuckle out of people like you... who the hell cares if you need to repeat yourself to help someone? people like you act like its a complete waste of your time yet you still reply.

thanks for posting the link, i already read thread before posting this thread.

StealthFRC

starter is new and all the wiring has been checked, car has twin turbos so ive had to mess with the starter quite often due to heat lol.


yea exactly, before posting i read a couple threads where people had luck with the auto zone alternators ones is labeled (tough one) but im not quite sure what store sells that one.
i honestly think my issue is to much load for the 110amp alternator to handle but im not 100% positive about it. im going to bring my original in to get tested today and see what happens.
my issues is more in the higher rpms while making a pull, i have a gauge that monitors and logs my voltage, it will go from 14v at start of pull to 11-12v.

Macleod52

I was not talking about your original alternator and I also saw that you kept your core. That is why I said have your original alternator rebuilt. What I am saying is that you bought an Autozone alternator and it throws a code. This is a known phenomenon and several people have posted the same issues you have. The C5's alternator is unique and is the reason why time, and time again, it is stated that you need to have your OEM alternator rebuilt. That thread also mentions that going from a 110amp alternator to the 145amp can also cause the charge system fault so you may be stuck with a 110amp one. You said you've read the thread yet you still are trying to troubleshoot why the Autozone alternator doesn't work right.

zrtman1

Might want to check cable better.. mine looked new ( nice and clean/no corrosion).. but moisture has got inside the end of the cable (in the sheathing for the first 1/2" and turned it green..). Probably not the case but something to look into. The starter lug being the common hot is not a good design imo (once they get some years on them).


Post up if you figure anything out. Same boat.. aux pumps pull volts down... I turn off ac, heater/blower fan and stereo/amp for play time/wot. 110amps (at best when new) is getting taxed.