C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

Odd electrical

Thread Tools
 
Search this Thread
 
Old Jul 24, 2011 | 11:40 AM
  #1  
1tuffref's Avatar
1tuffref
Thread Starter
Advanced
 
Joined: Oct 2004
Posts: 97
Likes: 0
From: Trumbull CT
Default Odd electrical

I am dropping system voltage on short runs and the engine is dying when I let the RPMs come down. The battery also goes dead but charges back up on a charger when I get it home. I thought it was a slipping alternator belt. I tightened it up and tried again with the same results. I checked and my alternator is putting out 14.5 Volts at high idle so I replaced the battery. Same thing. I am going to replace the alternator but was wondering if it could be anything else?
Reply
Old Jul 24, 2011 | 07:40 PM
  #2  
1tuffref's Avatar
1tuffref
Thread Starter
Advanced
 
Joined: Oct 2004
Posts: 97
Likes: 0
From: Trumbull CT
Default

Originally Posted by 1tuffref
I am dropping system voltage on short runs and the engine is dying when I let the RPMs come down. The battery also goes dead but charges back up on a charger when I get it home. I thought it was a slipping alternator belt. I tightened it up and tried again with the same results. I checked and my alternator is putting out 14.5 Volts at high idle so I replaced the battery. Same thing. I am going to replace the alternator but was wondering if it could be anything else?
I changed the alternator and same thing. I could really use some advice because I have never had this kind of porblem before.
Reply
Old Jul 24, 2011 | 07:44 PM
  #3  
...Roger...'s Avatar
...Roger...
Race Director
 
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Default

What year , what voltage do you have at the battery ?
Reply
Old Jul 25, 2011 | 09:37 AM
  #4  
1tuffref's Avatar
1tuffref
Thread Starter
Advanced
 
Joined: Oct 2004
Posts: 97
Likes: 0
From: Trumbull CT
Default

Originally Posted by ...Roger...
What year , what voltage do you have at the battery ?
1977. The battery is brand new. I have to check my voltage again tonight with a digiatl meter from work. Do you know if I have an external voltage regulator? If so I would thing that is next to change.
Reply
Old Jul 25, 2011 | 01:48 PM
  #5  
1tuffref's Avatar
1tuffref
Thread Starter
Advanced
 
Joined: Oct 2004
Posts: 97
Likes: 0
From: Trumbull CT
Default

Originally Posted by ...Roger...
What year , what voltage do you have at the battery ?
Engine off 13.5. Engine running 14.2 at battery posts. 14.5 at alternator hot output. Lights on engine dropped RPMs and picked up load. Voltage at alternator 14.4.
Reply
Old Jul 25, 2011 | 03:07 PM
  #6  
...Roger...'s Avatar
...Roger...
Race Director
 
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Default

Originally Posted by 1tuffref
Engine off 13.5. Engine running 14.2 at battery posts. 14.5 at alternator hot output. Lights on engine dropped RPMs and picked up load. Voltage at alternator 14.4.
That looks good to me. New battery,new alternator,what is your dash voltmeter doing during these short runs ? Does it ever dip below 13.5 ?

It sounds as if your saying above you think the reason the car dies is because the battery voltage has dropped and the ignition system is being starved , correct ?
Reply
Old Jul 25, 2011 | 09:37 PM
  #7  
1tuffref's Avatar
1tuffref
Thread Starter
Advanced
 
Joined: Oct 2004
Posts: 97
Likes: 0
From: Trumbull CT
Default

Originally Posted by ...Roger...
That looks good to me. New battery,new alternator,what is your dash voltmeter doing during these short runs ? Does it ever dip below 13.5 ?

It sounds as if your saying above you think the reason the car dies is because the battery voltage has dropped and the ignition system is being starved , correct ?
Dash volt meter drops a I cruise alnong and when I get off the fuel to shift the engine starts to die. If it does the starter is always sounding weak. After charging the battery full I did a test in my garage with the motor running. I started out charging at 14.5 volts and just let it idle with the blower on full and the head lights on. After a bit I killed the blower and head lights and ran it around the block. I let it keep running and it dropped dwon to 13.8 volts at the alternator even when I brought the RPMs up. I am taking it to my mechanic tomorrow. This is beyond me although if he tells me my new "remanufactured" alternator is bad I am going to blow a fit. The crazy thing is I have a very motivated buyer for it but would never sell a car that was not sound.
Reply
Old Jul 25, 2011 | 09:45 PM
  #8  
...Roger...'s Avatar
...Roger...
Race Director
 
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Default

Does the generator or battery light come on when the key is in the On position ? Does the generator or battery light come on while your driving ?
How does the neg battery cable look where it bolts to the frame ?
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-1

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-2

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
story-3

2027 Corvette vs The World: Every C8 vs Its Closest Competitor

 Joe Kucinski
story-4

10 Most Common Corvette Problems of the Last 20 Years!

 Joe Kucinski
story-5

5 MOST and 5 LEAST Popular Corvette Model Years in History!

 Joe Kucinski
story-6

2027 Corvette Buyer's Guide: Everything You Need to Know!

 Joe Kucinski
story-7

10 Things C8 Corvette Owners Hate (But Won't Tell You)

 Joe Kucinski
story-8

10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!

 Brett Foote
story-9

Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)

 Joe Kucinski
Old Jul 25, 2011 | 11:10 PM
  #9  
wombvette's Avatar
wombvette
Le Mans Master
15 Year Member
 
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
Default

Sounds like a bad alternator or regulator, which is inside the alternator. Take it back, get another one.
Reply
Old Jul 26, 2011 | 01:52 AM
  #10  
7T1vette's Avatar
7T1vette
Team Owner
15 Year Member
Community Builder
Community Influencer
Top Answer: 5
 
Joined: Jan 2006
Posts: 37,637
Likes: 3,113
From: Crossville TN
Default

I think you may have some bad connections on some of the power wiring. If the connections (or the wire, itself) is weak/bad, the battery can't get recharged, no matter how good the battery and/or alternator is. The fact that you are constantly seeing over 14 volts from the alternator indicates that the alt is sensing that the battery is discharged. So, I think you have a wiring problem in the main power circuits and/or the sensing loop to the alternator.
Reply
Old Jul 26, 2011 | 02:39 AM
  #11  
69Vett's Avatar
69Vett
Safety Car
15 Year Member
 
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
Default

DO Not assume "NEW" .... means working correctly.
Battery or Alternator.
Reply
Old Jul 26, 2011 | 08:06 AM
  #12  
...Roger...'s Avatar
...Roger...
Race Director
 
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Default

Originally Posted by 69Vett
DO Not assume "NEW" .... means working correctly.
Battery or Alternator.

I had a customer come in with a new battery from a Shell gas station,customer said it kept going dead,I tested and determined the new battery was bad, 4 new Shell battery's later I put in one of mine and he was back on the road. The Shell station was selling stale ,poorly stored battery's.
Reply

Get notified of new replies

To Odd electrical





All times are GMT -4. The time now is 02:04 PM.

story-0
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-1
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-2
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE
story-3
2027 Corvette vs The World: Every C8 vs Its Closest Competitor

Slideshow: 2027 Corvette lineup vs the world.

By Joe Kucinski | 2026-04-24 16:12:42


VIEW MORE
story-4
10 Most Common Corvette Problems of the Last 20 Years!

Slideshow: 10 major Corvette problems from the last 20 years.

By Joe Kucinski | 2026-04-14 16:37:05


VIEW MORE
story-5
5 MOST and 5 LEAST Popular Corvette Model Years in History!

Slideshow: 5 most and least popular Corvette model years.

By Joe Kucinski | 2026-04-08 13:25:01


VIEW MORE
story-6
2027 Corvette Buyer's Guide: Everything You Need to Know!

Slideshow: 2027 Corvette buyer's guide

By Joe Kucinski | 2026-04-17 16:41:08


VIEW MORE
story-7
10 Things C8 Corvette Owners Hate (But Won't Tell You)

Slideshow: 10 things C8 Corvette owners hate, but won't tell you.

By Joe Kucinski | 2026-04-01 18:36:07


VIEW MORE
story-8
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!

Slideshow: Should you add one of these incredible Corvettes to your garage?

By Brett Foote | 2026-04-01 18:14:05


VIEW MORE
story-9
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)

Slideshow: Every Corvette Grand Sport explained

By Joe Kucinski | 2026-03-26 07:13:44


VIEW MORE