ZR-1 Net Registry Forums  

Go Back   ZR-1 Net Registry Forums > C4 ZR-1 > C4 ZR-1 Technical Postings

Reply
 
Thread Tools Display Modes
Old 04-18-2014   #1
-=Jeff=-
 
-=Jeff=-'s Avatar
 
Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,169
Default Alternator going bad?

What are some of the signs?

I noticed today when I get on it at about the 5K RPM the voltage meter on the dash starts to drop (enough to see it move) not sure what voltage it drops to..

otherwise all seems fine.. Do I need to get a replacement again?
__________________
1990 Corvette ZR-1 #1051
Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback
Late Model IH - Plenum
Coilovers - 4.10s
Custom Interior
NCM Lifetime Member #978
-=Jeff=- is offline   Reply With Quote
Old 04-18-2014   #2
LGAFF
 
LGAFF's Avatar
 
Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,194
Default Re: Alternator going bad?

volts being all over is a definite sign its going, check your batter terminals first make sure its tight
__________________
LGAFF
90 #966-150K miles-sold
92 #234-sold
1987 Callaway TT #17
1991 ZR-1 #1359
LGAFF is offline   Reply With Quote
Old 04-18-2014   #3
LGAFF
 
LGAFF's Avatar
 
Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,194
Default Re: Alternator going bad?

or might be all of the high tech gadgets you are running in your car zapping the power
__________________
LGAFF
90 #966-150K miles-sold
92 #234-sold
1987 Callaway TT #17
1991 ZR-1 #1359
LGAFF is offline   Reply With Quote
Old 04-18-2014   #4
-=Jeff=-
 
-=Jeff=-'s Avatar
 
Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,169
Default Re: Alternator going bad?

Sure if it all over the place, but the Needle stay put until the RPMs climb past 4K, then the voltages fall, as soon as the RPMs drop it is fine.. I doubt the 12-5v ps I added is causing the issue.. Many people are using it.. Guess I will buy an Alternator to be safe
__________________
1990 Corvette ZR-1 #1051
Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback
Late Model IH - Plenum
Coilovers - 4.10s
Custom Interior
NCM Lifetime Member #978

Last edited by -=Jeff=-; 04-18-2014 at 04:17 PM.
-=Jeff=- is offline   Reply With Quote
Old 04-18-2014   #5
LantanaTX
 
Join Date: Mar 2014
Location: Lantana, TX
Posts: 134
Default Re: Alternator going bad?

Quote:
Originally Posted by -=Jeff=- View Post
Sure if it all over the place, but the Needle stay put until the RPMs climb past 4K, then the voltages fall, as soon as the RPMs drop it is fine.. I doubt the 12-5v ps I added is causing the issue.. Many people are using it.. Guess I will buy an Alternator to be safe
Most parts stores will check the charging system for free and put a load on it. I would do this before just throwing money at it.
__________________
[SIGPIC][/SIGPIC]1991 #0663
LantanaTX is offline   Reply With Quote
Old 04-18-2014   #6
-=Jeff=-
 
-=Jeff=-'s Avatar
 
Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,169
Default Re: Alternator going bad?

Quote:
Originally Posted by LantanaTX View Post
Most parts stores will check the charging system for free and put a load on it. I would do this before just throwing money at it.
Yeah but having a spare is always a good thing.. might buy a higher output one that was shown on here awhile back
__________________
1990 Corvette ZR-1 #1051
Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback
Late Model IH - Plenum
Coilovers - 4.10s
Custom Interior
NCM Lifetime Member #978
-=Jeff=- is offline   Reply With Quote
Old 04-18-2014   #7
Blue Flame Restorations
 
Blue Flame Restorations's Avatar
 
Join Date: Feb 2010
Location: Pendleton, IN
Posts: 3,904
Default Re: Alternator going bad?

When mine went out of my 9500, 95, the battery light came on the display eventually.

Evidently, the car had not had a battery tender on it for some time. It does now, always.
__________________
1988 KOH Prototype EX5023 sold
1990 ZR-1 #444 Convertible
1990 ZR-1 Black #966
1991 ZR-1 Quazar Blue #296
1957 Duntov SS Project
Blue Flame Restorations is offline   Reply With Quote
Old 04-18-2014   #8
WVZR-1
 
Join Date: Oct 2004
Posts: 1,890
Default Re: Alternator going bad?

Quote:
Originally Posted by -=Jeff=- View Post
What are some of the signs?

I noticed today when I get on it at about the 5K RPM the voltage meter on the dash starts to drop (enough to see it move) not sure what voltage it drops to..

otherwise all seems fine.. Do I need to get a replacement again?
You want to check the complete electrical "on the car" using a "Carbon Pile" load tester and a DMM. That's the only way to actually evaluate the system and it should be done before doing any alternator/generator OR starter replacement.
WVZR-1 is offline   Reply With Quote
Old 04-18-2014   #9
-=Jeff=-
 
-=Jeff=-'s Avatar
 
Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,169
Default Re: Alternator going bad?

OK, get down to 11 volts when at 5k rpm

Below that rpm it is high 12s, I will data log to a file next time
__________________
1990 Corvette ZR-1 #1051
Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback
Late Model IH - Plenum
Coilovers - 4.10s
Custom Interior
NCM Lifetime Member #978
-=Jeff=- is offline   Reply With Quote
Old 04-19-2014   #10
scottfab
 
scottfab's Avatar
 
Join Date: Jan 2009
Location: Portland Oregon metro area (Washington side)
Posts: 3,207
Default Re: Alternator going bad?

Quote:
Originally Posted by -=Jeff=- View Post
OK, get down to 11 volts when at 5k rpm

Below that rpm it is high 12s, I will data log to a file next time
Battery V should be at 14.5v or so at idle if alternator is doing it's thing.
__________________
Scott


Vett owner since 1979._It's about the car and the people
scottfab is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 03:07 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright ZR-1 Net Registry 2020