TT32VGT

Alright so I got my car back from the mechanic after heads and clutch..

battery dies.. I replaced battery and noticed the volts were getting into low 12s at idle and service charging system light came on..

Checked the alternator at autozone and while the volts tested okay he said he thinks the clutch is slippin.. u could see some play in the pulley and it was making unusual vibrating noise when tested so I got a rebuilt one from pepboys..

I replaced the alternator this morning and its idling into the low 12s again..

ive heard some say might be regulator.. Im pulling batter out now so charge it up..

Any ideas??

Thanks!!

erikszr1

Did you have anybody other than the parts store diagnose this? I would have bought a brand new one from GM. I have seen many cheapo rebuilds not work right out of the box. I would only buy car soap or wax from places like pep boys, autozone ect., maybe if the car was a older cavalier or Taurus maybe, a C6 corvette, no way.

TT32VGT

normally im the same, but many people on this forum have had good results with pep boys rebuilt units.. looks great..

JWingo

If you have Multi Meter, verify the voltage at the main charge lug on the rear of the alternator. I suspect you have a loose connection with excess voltage drop. Test before you spend your hard earned money.

z06clif

I think there was a post in the General section of a member having low volts and it turned out to be a bad connection at the starter(after a go around with the dealership)

Clif

teking

WELCOME TO MY WORLD !!!

And after a year of pain .... RESOLVED!! Yes I too had low volts at idle. I went to the dealer .... they gave up. Actually said they couldn't fix it ... and to come get it. Replaced everything you did to no avail. Including the ECU. I'd drop into the 11s.

My mechanic in Orlando .... who knew a guy ..... had him come up from Tampa. The guy resolved the issue in 10 minutes with a laptop. Said it was a known issue that GM refuses to acknowledge.

That was 4 years ago ...... have never looked back.

TT32VGT

hmm, mine has heads, cam, intake, exhaust and a few other things.. its been tuned too..
this sucks.. ive got the battery on a charger.. going to plug it back in tomorrow..
the mechanic has a performance shop on the side and has been a gm service manager for over 30yrs so he def knows his stuff.. he said its okay for the volts to get low at idle but real test is at 2k rpms..

Im going to try and go back over everything, see if everything is tightened up..

thanks for all the posts guys, keep em comin!

teking

As has mine. All the same problems as you. dead battery, etc. Remember I replaced the ECU and it STILL was there. I have since put MY ECU back in.

TT32VGT

man.. i dunno what to do. guess im going to find a volt meter and check the back of the alternator and the wire going from ecu to alternator..

not sure what that fix is that ur talkin about teking, he didnt say what it was?

teking

He didn't tell me what it was ... but the 5V returned!!!!

TT32VGT

right.. kinda hard to tell a mechanic/tuner that.. ya know? thx for your posts though.

anyone else got any recomendations?

thanks!

teking

Tell your tuner there is a setting in the ECU that controls when the 5V cuts on. And that you've heard adjusting that fixes the problem.

TT32VGT

thanks for the post! I will def try telling him that if I cant get it fixed soon..

Thanks again.


btw, the wire/nut that has the rubber cover on it, on the back of the alternator, is that the wire that I need to test for 5v at idle?

TT32VGT

after researching threads and all of the posts here, it seems like it can be:
-starter or wire from alternator to starter

-wire from alternator to ecu(check volts at back of alt)

-ecu

-a loose fastener

-fix in the tune

anyone wanna add anymore to the list lol

the volts seem to fluctuate a lot.. in all of my other cars the volts dont fluctuate much.. i honestly havent noticed before having these low volts prob..
my car has been cammed, intake, and exhaust for over a year.. it seems like the probs started after the head and clutch install..

'06 Quicksilver Z06

If it was tuned with HPTuners, then you can compare the new file with the stock tune.

Turbosixx

What rpms is it idling at? Who's tuning your car?
Check all the grounds. I bet one is loose.

ralphsmithiii

I started having the same issues recently as well and have yet to find a solution. I've had both my battery and alternator checked (replaced battery), swapped back to stock plugs, upgraded to MSD wires and when my car warms up to operating temps, the voltage just drops below 14v sometimes down to 12-12.5 when sitting idle.

It's strange how this is happening to some and it appears to only happen when the car warms up. I don't recall this being the norm but I also can't recall when it started happening either.

TT32VGT

idle is at 900 i believe..
stanghi did the first tune after the cam, intake, and ehxaust.. been like that for a year or so, never noticed probs before but honestly didnt pay attention to the volt meter.. darren blanchard did the street tune after the head/clutch install.
id love for it to be a loose ground wire.. lol.. maybe it is since they just did the clutch/head install.. im a total noob at working on this car.. i just did the alternator this morning for the first time.. where are some of the grounds?

TT32VGT

oh geez.. another one huh.. i keep findin these stories all over the net

Turbosixx

Not blaming the tune, but I would not let either one tune my car.

Usually when troubleshooting you need to look at the last thing that was done and start from there. Heads were removed and replaced....Starter wires could have been loosened (not sure why) when the clutch was changed. A lot of stuff gets removed when the clutch gets changed.
Check the ground on the back side of the passenger side head. Could be loose.