GM 1 wire alternator not charging battery - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

 
LinkBack Thread Tools Display Modes
post #1 of 13 (permalink) Old Jan 31st, 13, 09:41 AM Thread Starter
Matt
 
Join Date: Jan 2013
Location: North Carolina
Posts: 5
GM 1 wire alternator not charging battery

Hey, I have a 68 Camaro with a 400 small block. I just replaced the alternator which is a GM 1 wire alternator. A while back I had a headlight switch short out and fry my electrical system so I had the entire wiring harness replaced. Car was running fine until a few days ago. My starter went out so I replaced it and once again running fine. Today I find that my battery is dead and after jumping it the alternator light was on and not charging battery. Had the old one tested and it was bad, but the new one tested good at 3 different shops and is still not putting out any voltage. Is it possible that the solenoid on the starter is bad? The battery will hold a full charge and car starts and runs fine but there's no voltage coming off the alternator. I'm at a loss here.
Reaper138 is offline  
Sponsored Links
Advertisement
 
post #2 of 13 (permalink) Old Jan 31st, 13, 10:28 AM
Gold Lifetime Member
John
 
Vintage 68's Avatar
 
Join Date: Mar 2002
Location: Moraga,Ca.,USA
Posts: 13,705
Wink Re: GM 1 wire alternator not charging battery

You may want to spend a little time reading through - http://www.madelectrical.com/electri...hreewire.shtml

1968 Convertible
Some trucks
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Other V8 things - some of which float
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Other V6 things - none of which float
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Oh yeah, and 1 "Straight-Six" ...
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


If a man says something in the garage - and his wife can't hear him - is he still wrong !!!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Vintage 68 is offline  
post #3 of 13 (permalink) Old Jan 31st, 13, 12:03 PM Thread Starter
Matt
 
Join Date: Jan 2013
Location: North Carolina
Posts: 5
Re: GM 1 wire alternator not charging battery



Ignore the arrows in the picture, it was the best pic i could find.

This is what the old one looked like and it's also what the new one looked like. I took the old one to autozone and because it's not the stock engine in the car they were running around with their heads off because they couldn't use the computer to solve this problem. The guy ended up bringing the new one out and the box said GM 1 wire on it. The part number was DL7140M. I don't have the old one anymore but at this point I'm wondering if maybe I need a 3 wire with internal voltage regulator like in this picture? how do I tell the difference, they look identical. If it helps, i do have the GEN light in the dash and from what I read since that's lighting up I would think that I need a 3 wire but I have no idea.
Reaper138 is offline  
 
post #4 of 13 (permalink) Old Jan 31st, 13, 01:33 PM
Allen
 
Join Date: Oct 2012
Location: Upland, CA
Posts: 23
Re: GM 1 wire alternator not charging battery

I agree with Vintage '68 and bone up on the one wire alternators.

When I had my '71, I went to the one wire alternator and did not like it. The one wire setup would only charge the battery, under load. It was particularly noticeable at night when the lights were on. It was very annoying to have the lights dim, when your're stopped sitting at a light. As soon as the RPM's picked up, the lights would get brighter.

If you can, go back to the three wire setup.

Just my 02 cents.

A
Kunihiro is offline  
post #5 of 13 (permalink) Old Jan 31st, 13, 02:32 PM Thread Starter
Matt
 
Join Date: Jan 2013
Location: North Carolina
Posts: 5
Re: GM 1 wire alternator not charging battery

Massive Face Palm. Alternator wire was bolted to the wrong side of the starter solenoid. Turns out the alternator is also a 1 or 3 wire hook up.
Reaper138 is offline  
post #6 of 13 (permalink) Old Jan 31st, 13, 03:13 PM
Senior Tech
kevin
 
Join Date: Mar 2012
Location: virginia
Posts: 3,509
Re: GM 1 wire alternator not charging battery

Quote:
Originally Posted by Kunihiro View Post
I agree with Vintage '68 and bone up on the one wire alternators.

When I had my '71, I went to the one wire alternator and did not like it. The one wire setup would only charge the battery, under load. It was particularly noticeable at night when the lights were on. It was very annoying to have the lights dim, when your're stopped sitting at a light. As soon as the RPM's picked up, the lights would get brighter.

If you can, go back to the three wire setup.

Just my 02 cents.

A
not a problem with my one wire altenator, but i did have it built to 130 amps.
you can always go to a smaller pully on the altenator. that will speed it up and still maintain your rpm setting at idle
flat tire is online now  
post #7 of 13 (permalink) Old Jan 31st, 13, 03:28 PM
Gold Lifetime Member
John
 
Vintage 68's Avatar
 
Join Date: Mar 2002
Location: Moraga,Ca.,USA
Posts: 13,705
Wink Re: GM 1 wire alternator not charging battery

Quote:
Originally Posted by flat tire View Post
... can always go to a smaller pully on the altenator. that will speed it up and still maintain your rpm setting at idle
That would be a 'Larger' diameter Pulley - "to speed it up"

You do realize that an 'alternator' usually operates at @3 times faster than the crank speed of the engine - right ???

GM/Delco alternators are spec.d at;
@10k rpm for Continuous Duty shaft speed
@12K rpm for transient Intermittent shaft speed
@18K rpm as the Maximum shaft speed

So 'speeding it up' to much will have it throwing windings off the armature in a very short time.
Seen it happen and it's NOT a pretty sight

Designing and installing a fully functional charging system that operates under ALL conditions isn't Rocket-Surgery.
Lots of good posts/threads on this site with great info on how to do it ...

1968 Convertible
Some trucks
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Other V8 things - some of which float
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Other V6 things - none of which float
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Oh yeah, and 1 "Straight-Six" ...
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


If a man says something in the garage - and his wife can't hear him - is he still wrong !!!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Vintage 68 is offline  
post #8 of 13 (permalink) Old Jan 31st, 13, 07:45 PM
Senior Tech
mike
 
Join Date: Jan 2011
Location: east coast
Posts: 2,288
Re: GM 1 wire alternator not charging battery

He said a larger pulley on the alternator. That would indeed speed it up. Think of it this way if he had a pulley the size of a bike tire it would barely spin fast at all, if he had one the size of a pea it would spin insanely fast. I have read tons of posts 3 wire vs 1 wire and can get a million opinions on what is best. I just think it is what is available and what you like. However it is important to get enough amperage to suit your needs. The o.p. I think if the stores say the alternator is good and the gen light is on he made a mistake with the wiring he needs to figure out.
bigblockragtop is offline  
post #9 of 13 (permalink) Old Jan 31st, 13, 09:47 PM
Senior Tech
Al
 
Join Date: Nov 2002
Location: Vancouver, USA
Posts: 10,508
Re: GM 1 wire alternator not charging battery

Did you replace a 1 wire with another 1 wire? Hard to tell from your post. A 1 wire won't allow the factory gen light to work, hence the confusion.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
BPOS is offline  
post #10 of 13 (permalink) Old Feb 1st, 13, 11:37 AM Thread Starter
Matt
 
Join Date: Jan 2013
Location: North Carolina
Posts: 5
Re: GM 1 wire alternator not charging battery

It's a GM alternator that accepts both 1 and 3 wire hookups. After a lot of research, i'm running a 3 wire and have been the whole time. Problem was that I had the alternator wired to a ground instead of the postive terminal on the battery. Just had to unbolt it and swap it to the opposite post on the starter solenoid and now it's working perfectly. Next time I'm taking pictures and notes when I take something apart for the first time.
Reaper138 is offline  
post #11 of 13 (permalink) Old Feb 2nd, 13, 10:03 AM
Senior Tech
mike
 
Join Date: Jan 2011
Location: east coast
Posts: 2,288
Re: GM 1 wire alternator not charging battery

You said just had to swap it, did you mean you found out before you tried to connect the battery or after. Not sure what would happen if you did hook up the battery while the wires were backwards. Fry something maybe?
bigblockragtop is offline  
post #12 of 13 (permalink) Old Feb 3rd, 13, 12:34 PM Thread Starter
Matt
 
Join Date: Jan 2013
Location: North Carolina
Posts: 5
Re: GM 1 wire alternator not charging battery

No I had the battery hooked up before I figured it out. Alternator was just grounding out so no electrical damage. Got lucky this time.
Reaper138 is offline  
post #13 of 13 (permalink) Old Feb 9th, 13, 08:13 AM
Gold Lifetime Member
Dennis
 
madmax87's Avatar
 
Join Date: May 2001
Location: Arizona USA
Posts: 2,144
Re: GM 1 wire alternator not charging battery

Quote:
Originally Posted by Vintage 68 View Post
That would be a 'Larger' diameter Pulley - "to speed it up"

You do realize that an 'alternator' usually operates at @3 times faster than the crank speed of the engine - right ???

GM/Delco alternators are spec.d at;
@10k rpm for Continuous Duty shaft speed
@12K rpm for transient Intermittent shaft speed
@18K rpm as the Maximum shaft speed

So 'speeding it up' to much will have it throwing windings off the armature in a very short time.
Seen it happen and it's NOT a pretty sight

Designing and installing a fully functional charging system that operates under ALL conditions isn't Rocket-Surgery.
Lots of good posts/threads on this site with great info on how to do it ...
I know he solved his issue but I don't think the pulley question is answered correctly. They stated reducing the size of the alt pulley would speed it up. This is correct. Increasing the size of the crank pulley would also speed it up. If you had a 4" crank and 4" alt running at 700rpms, they would be the same. If you had a 4" crank and 2" alt, the alt would be spinning at 1400. So to get a 3 to 1 ratio with a 4" crank your alt would have to be 1.33"
http://www.culvermotor.com/Engineeri...alculator.html

Dennis
69 Z/28. 302DZ, Autogear M22, Red w/black stripes.
69 Camaro, ZZ4, 700R4, 8.5 3:42 posi, X11
70 Nova SS 396, 4sp, 3:55 12 bolt
madmax87 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome